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Habitats and ecological niches of chemolitho(auto)trophic bacteria
... Sulphate reducing and sulphur oxidizing bacteria (the latter producing H2SO4) have also been associated with the corrosion of pipes, tanks and other metallic structures. The sulphate reducers are thought to cause depolarization of the metal, resulting in electrochemical corrosion of structures such as oil platforms (Kuenen & Bos 1989). The sulphur oxidizing bacteria produce sulphuric acid which may also stimulate electrochemical corrosion . ...
... Since biotechnological processes tend to deal with much more concentrated sulphide solutions, and require higher specific rates of oxidation and low sludge production, the colourless sulphur bacteria from the genus Thiobacillus are clearly more appropriate for most applications. The 'colourless sulphur bacteria' is a general term of physiological, but little taxonomical significance (Kuenen 1989; Kelly & Harrison 1989). All of the physiological types outlined in Table 4can be found within this group. ...
... There are various physical methods which can be used for the removal of large pyrites crystals, but biological oxidation using the acidophilic Thiobacillus or Sulfolobus species (ironically, the same species that can cause environmental problems such as acid mine water and pipe corrosion) is particularly suitable for the treatment of coal containing finely distributed pyrite. It has been shown that such a process could be effective and feasible, especially for coals with a relatively low sulphur content (Bos et al. 1988; Bos & Kuenen 1989)o Laboratory studies showed that the process was most effective if carried out in two steps. In the first stage, the pulverized coal suspension is mixed with a suspension of suitable bacteria growing on pyrite at a (very low) pH (around 1.8). ...
Pollution by inorganic and organic sulphur compounds is increasing and, because of the many environmental hazards associated with these compounds (e.g. toxicity, acidification of rain and freshwater, increase of COD, the greenhouse effect), must be taken seriously. There is a wide variety of sulphur oxidizing bacteria available in nature, and these can be used for the effective control of such pollution. The best way to break the sulphur cycle is to stop it at sulphur which, being insoluble, can be easily recovered (e.g.SO4
2- S2- S0). (Eco)physiological knowledge about the sulphur oxidizing bacteria has proved very useful in the prediction of the performance of sulphur oxidizing communities in actual wastewater treatment systems. Appropriate reactor design, based on this type of study, is essential if such bacterial communities are to function efficiently, especially when toxic sulphides must be treated. This paper reviews the natural and anthropogenic sources of sulphur pollution, its consequences and possible solutions.
... Caves contain isolated environments within Earth's subsurface that are devoid of sunlight, making them an extreme environment for life (Northup and Diana, 2001). Low nutrients can encourage competition for limited resources which can lead to antimicrobial production to inhibit or eliminate surrounding microorganisms (Kuenen and Bos, 1989;Summers Engel et al., 2001;Fontaine et al., 2003;Zeppilli et al., 2018). ...
Microorganisms possess a variety of survival mechanisms, including the production of antimicrobials that function to kill and/or inhibit the growth of competing microorganisms. Studies of antimicrobial production have largely been driven by the medical community in response to the rise in antibiotic-resistant microorganisms and have involved isolated pure cultures under artificial laboratory conditions neglecting the important ecological roles of these compounds. The search for new natural products has extended to biofilms, soil, oceans, coral reefs, and shallow coastal sediments; however, the marine deep subsurface biosphere may be an untapped repository for novel antimicrobial discovery. Uniquely, prokaryotic survival in energy-limited extreme environments force microbial populations to either adapt their metabolism to outcompete or produce novel antimicrobials that inhibit competition. For example, subsurface sediments could yield novel antimicrobial genes, while at the same time answering important ecological questions about the microbial community.
... Defluviicoccus sp. is a glycogen-accumulating organism and typically active in enhanced biological phosphorus removal-activated sludge systems 32 . While Sulfurimonas sp. are known for their ability of catalyzing chemolithotrophic reactions with ferrous iron and pyrite and the reduction of nitrate and nitrite 33 , Arcobacter sp. are known ...
Nitrous oxide (N2O) is a potent greenhouse gas that also contributes to stratospheric ozone depletion. Besides microbial denitrification, abiotic nitrite reduction by Fe(II) (chemodenitrification) has the potential to be an important source of N2O. Here, using microcosms, we quantified N2O formation in coastal marine sediments under typical summer temperatures. Comparison between gamma-radiated and microbially-active microcosm experiments revealed that at least 15–25% of total N2O formation was caused by chemodenitrification, whereas 75–85% of total N2O was potentially produced by microbial N-transformation processes. An increase in (chemo)denitrification-based N2O formation and associated Fe(II) oxidation caused an upregulation of N2O reductase (typical nosZ) genes and a distinct community shift to potential Fe(III)-reducers (Arcobacter), Fe(II)-oxidizers (Sulfurimonas), and nitrate/nitrite-reducing microorganisms (Marinobacter). Our study suggests that chemodenitrification contributes substantially to N2O formation from marine sediments and significantly influences the N- and Fe-cycling microbial community.
... Nitrifiers are also classified as chemotrophs because they derive their energy from the oxidation of chemical compounds, as opposed to deriving energy from light for photosynthesis (phototrophs). Chemoautotrophs (also called chemolithotrophs) such as nitrifiers and sulfide oxidizers, and iron oxidizers are essential in the natural cycling of nutrients and can utilize reduced inorganic compounds that are derived from anthropogenic sources (e.g., mines, agriculture, and 1-1 combustion) as well as natural sources (e.g., volcanic, atmospheric, soil, fresh and sea water sediments, and the stomachs of ruminants) (Kuenen and Bos, 1989). Chemoautotrophs also play an important role in wastewater treatment. ...
Biochemical processes by chemoautotrophs such as nitrifiers and sulfide and iron oxidizers are used extensively in wastewater treatment. The research described in this dissertation involved the study of two selected biological processes utilized in wastewater treatment mediated by chemoautotrophic bacteria: nitrification (biological removal of ammonia and nitrogen) and hydrogen sulfide (H2S) removal from odorous air using biofiltration.
A municipal wastewater treatment plant (WWTP) receiving industrial dyeing discharge containing the azo dye, acid black 1 (AB1) failed to meet discharge limits, especially during the winter. Dyeing discharge mixed with domestic sewage was fed to sequencing batch reactors at 22oC and 7oC. Complete nitrification failure occurred at 7oC with more rapid nitrification failure as the dye concentration increased; slight nitrification inhibition occurred at 22oC. Dye-bearing wastewater reduced chemical oxygen demand (COD) removal at 7oC and 22oC, increased i effluent total suspended solids (TSS) at 7oC, and reduced activated sludge quality at 7oC. Decreasing AB1 loading resulted in partial nitrification recovery. Eliminating the dye-bearing discharge to the full-scale WWTP led to improved performance bringing the WWTP into regulatory compliance.
BiofilterTM, a dynamic model describing the biofiltration processes for hydrogen sulfide removal from odorous air emissions, was calibrated and validated using pilot- and full-scale biofilter data. In addition, the model predicted the trend of the measured data under field conditions of changing input concentration and low effluent concentrations. The model demonstrated that increasing gas residence time and temperature and decreasing influent concentration decreases effluent concentration. Model simulations also showed that longer residence times are required to treat loading spikes.
BiofilterTM was also used in the preliminary design of a full-scale biofilter for the removal of H2S from odorous air. Model simulations illustrated that plots of effluent concentration as a function of residence time or bed area were useful to characterize and design biofilters. Also, decreasing temperature significantly increased the effluent concentration. Model simulations showed that at a given temperature, a biofilter cannot reduce H2S emissions below a minimum value, no matter how large the biofilter.
... In fact, it is well known that many aerobic sulfur-oxidizing bacteria display positive chemotaxis toward such interfaces, and that they are able to form massive accumulations (Sorokin 1972, La Rivière & Schmidt 1982. It has been shown in cultured strains that specific growth rate, specific oxidation rates, carbon fixed per mole substrate oxidized, and affinity for oxygen are lower in ammonia oxidizers (Horrigan & Springer 1990) than in aerobic sulfur oxidizers (Kuenen & Bos 1987). If data from laboratory strains can be extrapolated to natural populations, sulfur oxidizers would easily outcompete ammonia oxidizers in marine oxic/anoxic interfaces (Ward 1984). ...
The present study assesses the contribution of dark carbon fixation to the primary production in the oxic/anoxic interface of a shallow estuarine environment that develops a salt-water wedge with the presence of sulfide. Primary production was partitioned into oxygenic photosynthesis, anoxygenic photosynthesis and dark fixation. The results show the importance of dark fixation in the oxic/anoxic interface with values higher than 5 mg carbon fixed per cubic meter and per hour in some cases. The average rate of primary production in the dark during the anoxic season for the Ebro River salt wedge resulted in 42 mg C m(-2) d(-1) in the interface. This represents at least twice the contribution of oxygenic photosynthesis to the primary production in such interface. Because this process is probably important in other salt-wedge or highly stratified estuaries with oxic/anoxic interfaces containing sulfide, the estimates of carbon fixation made so far for these systems may have been underestimated, and should therefore be revised taking into account the contribution of dark processes.
... The finding that the availability of electron donors for denitrification followed the concentration of H2S along the water column could be interpreted as suggesting the significance of reduced sulfur compounds as electron donors for denitrification. According to Kuenen & Bos (1987) chemolithoautotrophic thiobacilli are likely to be competitive at oxicanoxic interfaces. Since the ability to use both oxygen and nitrate as electron acceptors should be advantageous in this environment, an organism with similar physiological features to Thiobacillus denitrificans could be expected. ...
Denitrification was investigated in August 1986 and July 1987 in the water column of the Gotland Deep, an anoxic basin in the Baltic Proper. Denitrification rates were determined by means of the acetylene blockage method in the whole water column with emphasis on the low-oxygen water above the H2S-containing deep water. Denitrification was restricted to a layer of about 10 m at the oxic-anoxic interface (130 m depth), where NO3- and H2S coexisted. Rates in 1986 and 1987 were 110 and 44 nmol Nl-1 d-1 respectively. Samples from above the interface never showed denitrification, even after incubation periods of up to 12 d, obviously due to the combined effect of too high oxygen and too low carbon concentrations. Addition of nitrate to all samples enhanced denitrification only for H2S-containing water samples from the anoxic deep water. The coincidence of electron donor availability and H2S-concentration substantiated the hypothesis that reduced sulfur compounds could be valuable electron donors for denitrification by the bacterial community at the oxic-anoxic interface. Addition of sulfide or thiosulfate to water samples from just below the interface resulted in immediate denitrification of the added nitrate, with concomitant growth of the bacterial community. This indicates that denitrification in the oxic-anoxic interface could be efficiently driven by oxidation of reduced sulfur compounds provided by the anoxic deep water. Conceivable ecological implications of these findings are uncoupling of denitrification from carbon flux derived from phytoplankton primary production and strong dependence on mixing processes at the oxic-anoxic interface.
... Glucose utilization is a constitutive metabolic pathway, common among mixotrophic bacteria (Kuenen & Bos, 1989) and most fermenting, as well as respiring, heterotrophic bacteria. There was incorporation of glucose, which was below the detection limit for active bacteria (< 0.1 x 10-l6 mol per cell) in several samples analysed with the MARG method. ...
The incorporation of CO2 and assimilation of introduced organic compounds by bacterial populations in deep groundwater from fractured crystalline bedrock has been studied. Three depth horizons of the subvertical borehole V2 in the Stripa mine, Sweden, 799-807 m, 812-820 m and 970-1240 m, were sampled. The groundwaters, obtained from fracture systems without close hydraulic connections, were anoxic and had the following physicochemical characteristics: pH values of 9.5, 9.4 and 10.2; E(h) values of +205, +199 and -3mV; sulphide, 0, 106 and 233 μM; CO32-, 158, 50 and 57 μM; CH4, 245, 170 and 290 μl-1; and N2, 25, 31 and 25 mll-1. Biofilm reactors, each containing a series of parallel glass surfaces, were connected to the groundwaters issuing from these depth horizons at flows of approximately 1 x 10-3 m s-1 during two periods of two and four months. There were from 1.8 x 103 to 1.2 x 105 bacteria per ml groundwater and from 1.2 x 106 to 7.1 x 106 bacteria per cm2 of colonized test surface. These results imply that the populations of attached bacteria are several orders of magnitude greater than those of unattached bacteria in bedrock fractures with flowing groundwater. The incorporation of 14CO2, [14C]formate, [U-14C]acetate, [U-14C]glucose and L-[4,5,-3H]leucine by the bacterial populations was demonstrated using microautoradiographic and liquid scintillation counting techniques. The measured CO2 incorporation reflected the in situ production of organic carbon from CO2. Incorporation of formate followed that of CO2 and indicated the presence of bacteria able to substitute formate for CO2, e.g. methanogenic bacteria. The presence of sulphate-reducing bacteria is suggested by the observed incorporation of lactate by up to 74% of the bacterial populations. The recorded uptake of glucose indicates the presence of heterotrophic bacteria other than sulphate-reducing bacteria. Up to 99% of the populations incorporated leucine, showing that major fractions of the populations were viable.
... Under such low reactant conditions, chemical sulfi de oxidation becomes much slower due to the second order kinetics of the reaction (Zhang and Millero, 1994). Because of the Michaelis-Menthen kinetics of biological oxidation and the very low saturation constants for oxygen and sulfi de of 1 µM or below in chemolithotrophic sulfur bacteria (Kuenen and Bos, 1989; van den Ende and van), these organisms can still metabolize at maximal rates and may out-compete the chemical sulfi de oxidation (Zopfi et al., 2001a). ...
Most of the sulfide produced in surface marine sediments is eventually oxidized back to sulfate via sulfur compounds of intermediate oxidation state in a complex web of competing chemical and biological reactions. Improved handling, derivatization, and chromatographic techniques allowed us to more closely examine the occurrence and fate of the sulfur intermediates elemental sulfur (S0), thiosulfate (S2O32−), tetrathionate (S4O62−), and sulfite (SO32−) in Black Sea and North Sea sediments. Elemental sulfur was the most abundant sulfur intermediate with concentrations ~3 orders of magnitude higher than the dissolved species, which were typically in the low micromolar range or below. Turnover times of the intermediate sulfur compounds were inversely correlated with concentration and followed the order: SO3
2− ≈ S4O62− > S2O32− > S0. Experiments with anoxic but non-sulfi dic surface sediments from the Black Sea revealed that added sulfide and sulfite disappeared most rapidly, followed by thiosulfate. Competing chemical reactions, including the reaction of sulfite with sedimentary S0 that led to temporarily increased thiosulfate concentrations, resulted in the rapid disappearance of SO32−. Conversely, low thiosulfate concentrations in the
Black Sea sediments (<3μM) were attributed to the activity of thiosulfate-consuming bacteria. Experiments with anoxic but non-sulfi dic sediments revealed that 1 mol of tetrathionate was rapidly converted to 2 moles of thiosulfate. This tetrathionate reduction was bacterially mediated and occurred generally much faster than thiosulfate consumption. The rapid reduction of tetrathionate back to thiosulfate creates a
cul-de-sac in the sulfur cycle, with thiosulfate acting as a bottleneck for the oxidation pathways between sulfide and sulfate.
... A large variety of sulfur oxidizing bacteria capable of chemolithotrophy or photolithotrophy inhabiting di¡erent kinds of ecological niche were isolated [1]. However, knowledge on sulfur lithotrophy has been acquired primarily from the studies of colorless sulfur bacteria [2,3]. ...
We have isolated and characterized a double-stranded DNA bacteriophage (TPC-1) of Bosea thiooxidans, a facultative sulfur chemolithotrophic bacterium. The name 'thiophage' is introduced for phage(s) infecting sulfur chemolithotrophic bacteria. Electron micrographs showed the phage particle with an icosahedral head and a very short wedge-like tail. TPC-1 is classified as the C1 morphotype of the Podoviridae family. Restriction map and terminal ends detection by end fill labeling of the TPC-1 genomic DNA showed that the genome is linear with 5' protruding cohesive termini. Contour length mapping of the DNA genome also revealed it to be a linear fragment with size ( approximately 44 kb) corresponding with the size estimated from restriction fragment analyses and proved the non-redundant nature of the linear genome topology. In colorless sulfur chemolithotrophic microorganisms, TPC-1 is the first report of a generalized transducing thiophage.
... Nature harbors a large variety of bacteria which can derive energy from the oxidation of inorganic compounds (Table 1). Many use oxygen as electron acceptor but a number of them can also survive anaerobically using nitrate and ferric iron (Kuenen and Bos, 1989). Some obligate anaerobic chemolithotrophs are found among sulfate-reducers and the methanogenic bacteria. ...
Mine wastes have been generated for several centuries, and mining activity has accelerated significantly during the 20th century. The mine wastes constitute a potential source of contamination to the environment, as heavy metals and acid are released in large amounts. A great variety of microorganisms has been found in mine wastes and microbiological processes are usually responsible for the environmental hazard created by mine wastes. However, microorganisms can also be used to retard the adverse impact of mine wastes on the environment.
... Ž . Due to the very low saturation constants K for s y1 Ž oxygen and sulfide of 1 mmol l or below Kuenen and Bos, 1989; van den Ende and van Gemerden, . 1993 in chemolithotrophic sulfur-oxidizing bacteria, the sulfide oxidation rate in these organisms is rather Ž independent of the substrate concentrations O , 2 ...
Major electron donors (H2S, NH4+, Mn2+, Fe2+) and acceptors (O2, NO3−, Mn(IV), Fe(III)), process rates (35SO42− reduction, dark 14CO2 fixation) and vertical fluxes were investigated to quantify the dominant biogeochemical processes at the chemocline of a shallow brackish fjord. Under steady-state conditions, the upward fluxes of reductants and downward fluxes of oxidants in the water column were balanced. However, changes in the hydrographical conditions caused a transient nonsteady-state at the chemocline and had a great impact on process rates and the distribution of chemical species. Maxima of S0 (17.8 μmol l−1), thiosulfate (5.2 μmol l−1) and sulfite (1.1 μmol l−1) occurred at the chemocline, but were hardly detectable in the sulfidic deep water. The distribution of S0 suggested that the high concentration of S0 was (a) more likely due to a low turnover than a high formation rate and (b) was only transient, caused by chemocline perturbations. Kinetic calculations of chemical sulfide oxidation based on actual conditions in the chemocline revealed that under steady-state conditions with a narrow chemocline and low reactant concentrations, biological sulfide oxidation may account for more than 88% of the total sulfide oxidation. Under nonsteady-state conditions, where oxic and sulfidic water masses were recently mixed, resulting in an expanded chemocline, the proportion of chemical sulfide oxidation increased. The sulfide oxidation rate determined by incubation experiments was 0.216 μmol l−1 min−1, one of the highest reported for stratified basins and about 15 times faster than the initial rate for chemical oxidation. The conclusion of primarily biological sulfide oxidation was consistent with the observation of high rates of dark 14CO2 fixation (10.4 mmol m−2 day−1) in the lower part of the chemocline. However, rates of dark 14CO2 fixation were too high to be explained only by lithoautotrophic processes. CO2 fixation by growing populations of heterotrophic microorganisms may have additionally contributed to the observed rates.
... Under such low reactant conditions, chemical sulfi de oxidation becomes much slower due to the second order kinetics of the reaction (Zhang and Millero, 1994). Because of the Michaelis-Menthen kinetics of biological oxidation and the very low saturation constants for oxygen and sulfi de of 1 µM or below in chemolithotrophic sulfur bacteria (Kuenen and Bos, 1989;van den Ende and van Gemerden, 1993), these organisms can still metabolize at maximal rates and may out-compete the chemical sulfi de oxidation (Zopfi et al., 2001a). ...
Thesis (doctoral)--Universität Bremen, 2000.
... The phylogenetic affinities of some of the microbial groups from our 16S rRNA gene sequence clone libraries highlight that other, non sulfur-oxidizing, chemolithoautotrophic metabolic groups might be present (Figure 4), and we recognize that other autotrophic, energy-yielding pathways are possible (e.g., Kuenen & Bos, 1989;Stevens, 1997;Kinkle & Kane, 2000). Aerobic chemolithoautotrophic processes, where oxygen is used as the electron acceptor, are more energetic than anaerobic processes. ...
Although ecosystems thriving in the absence of photosynthetic processes are no longer considered unique phenomena, we haveyet to understand how these ecosystems are energetically sustained via chemosynthesis. Ecosystem energetics were measuredin microbial mats from active sulfidic caves (Movile Cave, Romania; Frasassi Caves, Italy; Lower Kane Cave, Wyoming, USA; andCesspool Cave, Virginia, USA) using radiotracer techniques. We also estimated bacterial diversity using 16S rRNA sequences torelate the productivity measurements to the composition of the microbial communities. All of the microbial communities investigatedwere dominated by chemolithoautotrophic productivity, with the highest rates from Movile Cave at 281 g C/m2/yr. Heterotrophicproductivities were at least one order of magnitude less than autotrophy from all of the caves. We generated 414 new 16S rRNAgene sequences that represented 173 operational taxonomic units (OTUs) with 99% sequence similarity. Although 13% of theseOTUs were found in more than one cave, the compositions of each community were significantly different from each other (P≤0.001).Autotrophic productivity was positively correlated with overall species richness and with the number of bacterial OTUs affiliated withthe Epsilonproteobacteria, a group known for sulfur cycling and chemolithoautotrophy. Higher rates of autotrophy were also stronglypositively correlated to available metabolic energy sources, and specifically to dissolved sulfide concentrations. The relationship ofautotrophic productivity and heterotrophic cycling rates to bacterial species richness can significantly impact the diversity of highertrophic levels in chemolithoautotrophically-based cave ecosystems, with the systems possessing the highest productivity supportingabundant and diverse macro-invertebrate communities.
... In cyanobacteria, three nonhomologous bicarbonate-transporting systems and two forms of carboxysomes are scattered among the different clades (2,24). Other autotrophs inhabit microhabitats even more disparate than those where cyanobacteria flourish (17) and embrace an astounding degree of phylogenetic and physiological diversity (at least four divisions of Bacteria and Archaea). Perhaps this ecological and phylogenetic diversity is reflected in a genetic and mechanistic diversity of CCMs. ...
How do individuals survive, develop, and grow in their environment? The multitude of challenges falls into two major categories:
Coping with the abiotic environment, i.e., basically the physical (e.g., temperature, pressure, wave energy) and chemical conditions (e.g., salinity) which set limits to survival and may be more or less favorable within those limits.
Beyond survival of abiotic stressors, organisms also have to extract resources from their environment, i.e., energy and substances needed for the production of their own body mass and for supporting their activity. At the same time, also materials are returned to the environment, consisting of “wastes,” i.e., end products of metabolism, and of architectural material, e.g., substances to build shells, reefs, etc. The matter and energy exchange with the environment is coupled to an internal transformation of matter and energy, called metabolism. There are two main categories of metabolic transformations: The processes building up biomass, called anabolism or assimilatory metabolism, and those processes which gain energy for maintenance and activity, called catabolism or dissimilatory metabolism.
Carbon dioxide (CO2) is one of the major greenhouse gases (GHGs), whose concentration has increased from 270 ppm to approximately 400 ppm after industrial revolution. Increase in CO2 concentration may be mitigated by autotrophic and heterotrophic carbon fixation by plants and microorganisms. Some microorganisms are able to grow in limiting CO2 concentrations by employing a CO2-concentrating mechanism (CCM) by enzymes mainly ribulose-1,5-bisphosphate carboxylase/ oxygenase (RuBisCO) and carboxylating enzymes such as carbonic anhydrase which facilitate the CO2 fixation. Genomics, Proteomic and metabolomics analysis has become a powerful tool to identified novel genes and protein for fixation of CO2 and evaluation of enzymes and metabolites for production of value added products. Chemolithotrophic microorganisms can sequester CO2 and synthesize valuable products such as different types of alkanes/alkenes, fatty acids, PHA, EPS which can be further utilized as raw materials for production of other bio-products.
Serratia sp. ISTD04 isolated from marble mines is a novel organism which performs chemolithoautotrophic CO2 assimilation. Genomic analysis of Serratia sp. ISTD04 revealed the presence of PRK and other CBB pathway genes. However, the RuBisCo gene could not be identified in the genome assembly. The carbonic anhydrase, AN important enzyme which facilitate the sequestrating mechanism of CO2 is also present in the genome. Enzymes like phosphoenolpyruvate (PEP) carboxylase, malic enzymes, and PEP carboxykinase, which help in anaplerotic assimilation of CO2, are also present in the genome of Serratia sp. ISTD04. Important transcriptional regulator, such as LTTR, HTH type and CysB- like protein transcription regulator which are known for CO2 fixation are also identified in the genome. EPS biosynthesis ability of this strain is also investigated at genomic level, presence of various EPS synthesis enzymes such as UDP-glucose 6-dehydrogenase, phosphoglucomutase, Galactose-1-phosphate uridylyltransferase, UDP-galactose-4-epimerase, Mannose-6-phosphate isomerase, phosphomannomutase, glucans biosynthesis glucosyltransferase H, polysaccharide biosynthesis protein, capsular polysaccharide translocation, glycogen/starch/alpha-glucan phosphorylases
family protein and many more in the genome, confirm this strain as an potential candidate for EPS production. This strain is well known fatty acid production; Enzymes for fatty acid metabolism such as acetyl-CoA carboxlases, malonyl Co-ACP transacylase, 3-ketoacyl ACP-synthase, and 3-ketoacyl ACP-reductase are identified in the genome. Cluster analysis of PHA biosynthesis revealed the presence of enzymes like β-ketoacyl-CoA thiolase and acetoacetyl-CoA dehydrogenase, which as well known for PHA biosynthesis. Genomic analysis of this strain confirmed that; this strain could be used as potential candidate for simultaneous sequestration of CO2 as well as production of biological materials.
CaCO3 precipitated by CO2 sequestering Serratia sp. ISTD04 were used as raw material along with NaNO3 and Si for the synthesis of biocomposite material by sol-gel process under ambient environmental condition has been performed successfully. The material synthesized by sol-gel process have essential features similar to Na2O-containing bioactive materials, mainly the formation of crystalline phase Na2Ca2Si3O9 after sintering the material at 1200 °C for 2 h and formed hydroxyl apatites like amorphous phase when its incubated in SBF, 1.5SBF and DMEM for 25 days without losing its crystallinity, this study showed that this material exhibits good bioactivity, biodegradability as well as mechanical properties. Ions exchange ability of this material in aqueous environment was analyzed by ICP-MS analysis and result confirmed the exchange of ions takes place between the material and aqueous environment, which favour the formation of hydroxyl apatites. MTT-assay confirmed that this material and their supernatant did not have any cellular cytotoxicity so this material could be use in biomedical application, although various analysis still required before its application in biomedical field.
Screening of CO2 sequestering chemolithotrophic bacteria Serratia sp. ISTD04 for production of biomass and PHA, further optimization of process parameters were performed by using statistical approach Response Surface Methodology (RSM) for improved production of PHA and biomass. The bacterial strain was screened for PHA production based on Nile red staining followed by visualization under fluorescence microscope. Spectrofluorometric measurement of Nile red fluorescence of the bacterial culture was also done. Confirmatory analysis of PHA accumulation by GC–MS revealed the presence of 3-hydroxyvalerate (PHV), which is a co-polymer of polyhydroxybutrate (PHB). Detection of characteristic peaks in the FT-IR spectrum further confirmed the production of PHA by the bacterium. RSM was used for
optimization of pH and carbon sources concentrations for higher PHA production. The result of optimization experiment revealed, almost a 2 fold increment in the production of PHA as compare to un-optimized condition. Thus this study establishes the production of PHV by Serratia sp. ISTD04.
This study highlights the possibility of production of biomaterial such as EPS by chemolithotrophic bacteria utilizing NaHCO3 and glucose as carbon source. Further characterization of EPS was performed by SEM, EDX, GC-MS, FT-IR, NMR and its constituent like total sugar, reducing sugar, protein content and fatty acid content was estimated. The work also demonstrates the optimized production of EPS at shake flask level and the optimized condition was adopted for production of EPS at fementor level in feed-batch mode for scale-up the production and its environmental application such as removal of various dyes. Finally proteomics analysis of Serratia sp. ISTD04 and cluster analysis of genes of chemolithtrophic Serratia sp. ISTD04 highlight the involvement of various proteins and genes in the production of EPS along with CO2 sequestration.
Diese Kapitel nimmt eine zentrale Stellung im gesamten Buch ein. Bereits bei der Darstellung des physikalischen und des chemischen Lebensraumes waren Vorgriffe auf die Ernährung der Plankter nötig. Ohne den Stoffwechsel der Plankter, der die Aufzehrung von Nahrungsressourcen und die Abgabe von Endprodukten an die Umwelt beinhaltet, wären weder die räumliche noch die zeitliche Verteilung vieler Inhaltsstoffe des Wassers erklärbar. Selbst die vertikale Verteilung des photosynthetisch nutzbaren Lichts hängt zu einem großen Teil von der Zehrung durch phototrophe Plankter ab. In noch stärkerem Maß werden die folgenden Kapitel auf Nahrungsbeziehungen aufbauen. Weder das Wachstum von Populationen noch die Interaktionen zwischen Populationen (Konkurrenz, Räuber-Beute-Beziehungen usw.) noch der Beitrag des Planktons zu lokalen und globalen Stoffkreisläufen lassen sich ohne Bezug zu seiner Ernährung erklären. Letztendlich sind die meisten Umweltbezüge der Organismen in der Notwendigkeit zur Ernährung und den daraus resultierenden Aktivitäten begründet.
Lavoisier, Chemiker und Vater der wissenschaftlichen Physiologie (1743–1794), verglich Organismen mit einer Flamme: Oxidierende Moleküle betreten sie an ihrer Wurzel und verlassen sie an ihrer Spitze. Die Flamme bleibt dennoch dieselbe, obwohl sie ständig von neuen Substanzen durchflossen wird. Dieser ständige Stoffwechsel mit der Umwelt und innerhalb des eigenen Körpers ist auch ein charakteristisches Merkmal des Lebens. Er ist ein ständiges Nehmen und Geben von chemischen Substanzen und hat dabei zwei Aspekte: den Aufbau eigener Körpersubstanz aus Fremdmaterialien (Baustoffwechsel) und die Bereitstellung von Energie für die Lebensprozesse aus der Oxidation organischer Substanzen (Betriebsstoffwechsel). Den Baustoffwechsel bezeichnet man auch als assimilatorischen Stoffwechsel, da Fremdsubstanz in die eigene Körpersubstanz eingebaut wird. Den Betriebsstoffwechsel bezeichnet man auch als dissimilatorischen Stoffwechsel, da eigene Substanz dem Körper wieder „entfremdet“ wird.
Microorganisms, such as the bacteria Thiobacillus ferrooxidans, have been reported to depress pyrite flotation (Elzeky and Attia, 1987; Atkins, 1990). However, the dependence of the depression on the type of organism or on suspension pH is still being determined. In this study, the relative effectiveness of various microorganisms (chemolithotrophic bacteria, chemoorganotrophic bacteria and yeast) over the pH range of 2 to 12 was studied. Screening tests using micro flotation showed that every microorganism tested was capable of depressing naturally hydrophobic pyrite at acidic pH. Larger-scale experiments with both mineral pyrite and coal pyrite using Thiobacillus ferrooxidans and Saccharomyces cerevisiae as depressants, showed that these microorganisms ale very effective depressants for mineral pyrite at acid pH, but they are largely ineffective at neutral and alkaline pH, where the mineral pyrite surface is not naturally hydrophobic. The flotation response of the coal pyrite was completely different from the mineral pyrite. The coal pyrite was most floatable near neutral pH, with the floatability decreasing in acidic or alkaline solutions. Depression of the coal pyrite by yeast was not selective between the pyrite and the associated coal under the experimental conditions.
This chapter deals with the genera Achromatium, Macromonas, Thiobacterium, Thiospira, and Thiovulum (see Fig. 1). They all belong to chemotrophic microbial populations generally encountered in natural habitats that are characterized by the simultaneous presence of H2S and O2, i.e., at the border between aerobic and anaerobic zones in surface waters and in the outflows of H2S-bearing springs. It will be useful to introduce this discussion with some general remarks on the special nature of this ecological niche to help explain the embarassing paucity of knowledge we possess about its inhabitants.
Microorganisms play key roles in the assimilation—dissimilation steps and oxidation-reduction processes of the global sulfur cycle. The dissimilatory reduction of sulfur compounds is an essential step in the biological sulfur cycle (LeGall and Fauque, 1988; LeFaou et al., 1990; Fauque et al., 1991; Widdel and Hansen, 1992). This dissimilatory reduction is due mainly to sulfur- and sulfate-reducing bacteria which perform anaerobic oxidative phosphorylation with elemental sulfur, sulfite, or sulfate as terminal electron acceptors (Barton et al., 1972; Fauque et al., 1980, 1991). These bacteria produce large amounts of sulfide, the oxidation of which permits energy generation by phototropic and chemolithotrophic microorganisms (Trüper, 1984).
The nutritional responses of unattached and attached bacterial communities were studied in groundwater from 3 sampling depths, i.e., 830-841 m, 910-921 m, and 999-1,078 m, of the subvertical borehole KLX01 at the Laxemar study area in SE Sweden. The salinity profile of the groundwater in this borehole is homogeneous. There were negative redox potentials (Eh) in the waters (-220 to -270 mV) and they contained sulfide, hydrogen, and methane. Biofilm reactors with hydrophilic glass surfaces were connected to the flowing groundwaters from each of the 3 depths with flow rates of approximately 3 x 10(-3) m sec(-1) over 19 days. There were 0.15 to 0.68 × 10(5) unattached bacteria ml(-1) groundwater and 0.94 to 1.2 × 10(5) attached bacteria cm(-2) on the surfaces. The assimilations of (14)CO2, (14)C-formate, 1,2,3-(3)H-acetate, U-(14)C-lactate, U-(14)C-glucose, and L-4,5-(3)H-leucine by the communities were demonstrated with microautoradiographic and liquid scintillation counting techniques. There were significant assimilations of CO2 by all communities, except for the unattached bacteria at the 910-921 m depth, indicating in situ production of organic carbon from carbonate. Assimilation of formate was detected in two communities, indicating the presence of bacteria able to substitute CO2 with formate. Acetate, lactate, and glucose assimilations demonstrated the presence of heterotrophic bacteria. The assimilation of lactate by the attached bacteria dominated over acetate and glucose at all depths. Leucine was assimilated by 20 to 98% of the communities, which showed that major portions of the communities studied were viable. The results indicate that the attached communities at the 830-841 m and 910-921 m depths were in more metabolically active states than the unattached bacteria. Incubation in air compared with N2 indicated that portions of the studied communities were obligate anaerobes, as their ability to assimilate the added compounds was sensitive to oxygen. The results show that the use of several different compounds reduces the risk for false conclusions about the viability and the metabolic activity of the deep groundwater communities.
Most large-scale processing ventures are initiated by ill-defined statements of need rather than by the discovery of either a new product or a novel process route. One of the best examples that has been contrary to this general pattern during the past decade has been the dramatic development of biotechnology, where one has seen both products and processes emerging as a result of research push rather than market pull. In contrast to this, environmental biotechnology is developing in response to a perceived need; the clean-up of indiscriminate pollution that has occurred from the advent of the industrial revolution until relatively recent times. With increasing public awareness and sensitivity to the crises that either have or will develop with respect to enviromental safety, health and quality, it is only now that politico-economic policies are being implemented that allow the development of technological responses to such crises. Newly evolving bioremediation and biorestoration technologies for soil and ground water clean-up, respectively, represent only one response scenario. Their future will depend on both their efficacy and their economics. Unless they continue to offer clear advantages on both counts, they will rapidly become obsolete. The maintenance of their relative attractiveness depends on the effectiveness and availability of underpinning fundamental research and its exploitation in solving practical problems.
Symbiotic filamentous bacteria thrive in the intestinal caecum of the deposit-feeding echinoid Echinocardium cordatum. Specimens of E. cordatum were collected at Wimereux (Nord Pas-de-Calais, France) in 1991. Their symbiotic bacteria build nodules by forming multilayered mats around detrital particles that enter the caecum. The morphological features of the bacteria are those of Thiothrix, a sulfide-oxidizing genus. The filaments, which may form rosettes, are sheathed and made by a succession of hundreds of rod-shaped bacteria which store elemental sulfur in the presence of external sulfide. Live bacteria are restricted to the outer layers of the nodules. Their sulfide-oxidizing activity was investigated, using a Biological Oxygen Monitor, by measuring the O2-consumption when reduced sulfur compounds are provided. They oxidize thiosulfate and sulfide. Optimal sulfide oxidation occurs at intermediary pO2 (100 to 160 M O2l-1). Spectrophotometry has confirmed that the sulfur content of the filamentous symbiotic sulfideoxidizing bacteria depends on the presence of external sulfide. This is the first report of symbiotic intradigestive Thiothrixspp.-like bacteria; it lengthens the list of symbioses between sulfide-oxidizing bacteria and invertebrates from sulfide-rich habitats.
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The name “the colorless sulfur bacteria” has been used since the time of Winogradsky to designate prokaryotes that are either able, or believed to be able, to use reduced sulfur compounds (e.g., sulfide, sulfur, and organic sulfides) as sources of energy for growth. Today, it is known that this group comprises a very heterogeneous collection of bacteria, many of which have little or no taxonomic relationship to each other. The colorless sulfur bacteria play an essential role in the oxidative side of the sulfur cycle (Fig. 1). Like all of the element cycles, the sulfur cycle has an oxidative and a reductive side, which, in most ecosystems, are in balance. However, this balance does not always exist, and accumulations of intermediates such as sulfur, iron sulfides, and hydrogen sulfide are often found. On the reductive side, sulfate (and sometimes elemental sulfur) functions as an electron acceptor in the metabolic pathways used by ...
A CO2-fixing bacterium, strain YN-1, that can fix CO2 under chemoautotrophic conditions but not photoautotrophic conditions was isolated from seawater. Identification of the isolate was carried out using biochemical tests and 16S rDNA sequence analysis, and its characteristics were investigated. From the results of partial 16S rDNA sequence analysis, strain YN-1 showed low identity with previously reported hydrogen-oxidizing bacteria, Hydrogenovibrio marinus MH-110 and Hydrogenophilus thermoluteolus. This result indicates that strain YN-1 may be a new hydrogen-oxidizing marine bacterium. Strain YN-1 showed considerable CO2 fixation ability during continuous cultivation even at high CO2 concentration. Strain YN-1 used H2 and CO2 as energy and carbon sources, respectively. Growth characteristics were examined in batch and continuous cultivation with a view to improving the CO2 fixation rate. The results showed that CO2 fixation occurred in the absence of a light source and that the strain exhibited good growth at high CO2 concentration (40%). On the other hand, the dry cell weight was 13.4 g/l following continuous cultivation for 76 h in 10% CO2 (0.1 l/min), and at that time the amount of fixed CO2 was 18.08 g CO2/l. This indicates that strain YN-1 can efficiently fix CO2 even at high CO2 concentrations, which would allow its application to the removal of industrially discharged CO2.
Nitrogen fluxes and processes were estimated in sandy and muddy sediments from the shallow eutrophic lake Nuldernauw, The Netherlands. N2, NH4+, NOx− and CH4 fluxes were measured from sediment samples collected throughout the year and incubated under both oxic and anoxic conditions at 2, 12 and 23°C. Fluxes increased with temperature with a mean temperature factor of 1.9±0.3 for a 10°C increase for both sediment types. At the same temperature the total N fluxes (N2+NOx−+NH4+) from the muddy sediments were generally larger than those from the sandy sediments. These differences are related to the relatively high availability of decomposable organic matter in the muddy sediments compared to the sandy sediments. Especially the denitrification was influenced by the organic matter content: 75–90% of the total N flux was denitrified by the muddy sediment whereas only 45–65% was denitrified by the sandy sediments. NH4+ fluxes were much higher and NOx− fluxes were much lower in cores collected just after spring bloom of phytoplankton, compared to cores collected during other periods. This effect was most pronounced at the high incubation temperature. The freshly settled and easily degradable organic matter at the top of the sediment appeared to be of great influence. Based on the results a general concept, combining the effects of temperature and (easily degradable) organic matter on N loss due to the coupled denitrification, was postulated. The concept implies that the coupled denitrification initially increases with increasing contents of (fresh) organic matter and/or temperature. By a further increase of organic matter or temperature, however, more oxygen is consumed by the aerobic mineralization and the CH4 oxidation and little or no oxygen remains available for the oxidation of nitrogen. Consequently no or less coupled denitrification can occur. Although high temperatures are not often found in the Dutch surface waters, these conditions can occur in spring and summer. Then nitrogen removal from the sediment–water system by the coupled nitrification–denitrification will be reduced and ammonium will be released to the overlying water where it can be consumed by algae.
El presente trabajo se centró en el estudio de una presa de decantación de residuos piríticos procedentes de una planta de procesamiento de sulfuros polimetálicos situada en la Faja Pirítica del suroeste español. El estudio se realizó en cinco etapas. en la primera de ellas se llevó a cabo la caracterización de la presa de residuos. La caracterización química del agua de la presa se llevó a cabo a través del control del pH, potencial redox, conductividad y la medida de la concentración de metales y sulfatos en solución. Desde un punto de vista microbiológico, el estudio se centró en la búsqueda de microorganismos directamente relacionados con los procesos de oxidación y edución: bacterias hierro y azufre oxidantes y bacterias reductoras de sulfatos. En la segunda etapa del estudio se analizó la influencia de los distintos factores que afectan a la transformación del residuo pirítico, para lo cual se realizaron tres ensayos de meteorización. Dichos ensayos fueron los siguientes: un ensayo estático (ABA) y dos ensayos cinéticos (ensayos en erlenmeyer con agitación y en columna, respectivamente). Los ensayos en matraz agitado se realizaron para determinar el comportamiento de los residuos bajo la influencia de dos factores: catálisis bacteriana y las condiciones reductoras inducidas por la presencia de iones sulfito en el sistema. El estudio de la oxidación química del ión sulfito y su influencia en la calidad del efluente fue de gran importancia porque este ión provoca unas condiciones reductoras en el sistema, que influyen en las características químicas del agua: pH, metales en solución, etc. El tercer objetivo del estudio fue reproducir la evolución de los residuos en la presa con un modelo en columna. La situación del sistema real se reprodujo a través de un modelo consistente en dos columnas: una de ellas (columna S) reproducía la parte del mineral bajo el agua; la otra (columna H-S), representaba a aquella parte del sistema en la que el mineral estaba sometido a cicloes de humedad y sequedad. En íntima conexión con la transformación del mineral, la actividad de los microorganismos puede aparecer asociada a los procesos oxidativos o a las reacciones de reducción. La selección y sucesión microbiológicas se estudiaron a través del modelo en columna elegido. Finalmente, se investigó el potencial de uan población mixta de bacterias reductoras de sulfatos (BRS) aisladas del fondo de la presa de residuos para el tratamiento del efluente generado en la propia mina.
Mixed cultures of a heterotrophic nitrifier/aerobic denitrifier, Thiosphaera pantotropha, and an autotrophic nitrifier, Nitrosomonas europaea, were grown in chemostats under dual ammonia-and acetate limitation. Because of simultaneous nitrification and denitrification by T. pantotropha, the activity of the cultures was evaluated from nitrogen balances as complete as possible. Under most conditions studied, no interaction took place between the two bacteria. Only above a critical C/N ratio of 10.4, T. pantotropha was able to outcompete N. europaea for ammonia (dilution rate = 0.04 h⁻¹). At dissolved oxygen concentrations below 10 μM, the autotroph became oxygen-limited and the heterotroph dominated in the culture. Moreover, when the dilution rate was increased to 0.065 h⁻¹, N. europaea could not maintain itself successfully in the chemostat, even when the C/N ratio was as low as 2.2. Nitrification by T. pantotropha was equivalent to that of N. europaea when the cell ratio of heterotrophs/autotrophs was 250. The relevance of these observations to the nitrogen cycle in natural environments is discussed.
The last decade has seen significant advances in our understanding of the physiology, ecology, and molecular biology of chemoautotrophic bacteria. Many ecosystems are dependent on CO2 fixation by either free-living or symbiotic chemoautotrophs. CO2 fixation in the chemoautotroph occurs via the Calvin-Benson-Bassham cycle. The cycle is characterized by three unique enzymatic activities: ribulose bisphosphate carboxylase/oxygenase, phosphoribulokinase, and sedoheptulose bisphosphatase. Ribulose bisphosphate carboxylase/oxygenase is commonly found in the cytoplasm, but a number of bacteria package much of the enzyme into polyhedral organelles, the carboxysomes. The carboxysome genes are located adjacent to cbb genes, which are often, but not always, clustered in large operons. The availability of carbon and reduced substrates control the expression of cbb genes in concert with the LysR-type transcriptional regulator, CbbR. Additional regulatory proteins may also be involved. All of these, as well as related topics, are discussed in detail in this review.
Partitioning of CO(2) incorporation into oxygenic phototrophic, anoxygenic phototrophic, and chemolithoautotrophic guilds was determined in a freshwater lake (Lake Cisó, Banyoles, Spain). CO(2) incorporation into the different types of microorganisms was studied at different depths, during diel cycles, and throughout the year. During winter holomixis, the whole lake became anoxic and both the anoxygenic and chemolithoautotrophic guilds were more active at the surface of the lake, whereas the activity of the oxygenic guild was negligible. During stratification, the latter guild was more active in the upper metalimnion, whereas the anoxygenic guild was more active in the lower metalimnion. Specific growth rates and doubling times were estimated for the most conspicuous phototrophic microorganisms. Doubling times for Cryptomonas phaseolus ranged between 0.5 and 192 days, whereas purple sulfur bacteria (Chromatiaceae-like) ranged between 1.5 and 238 days. These growth rates were similar to those calculated with a different approach in previous papers and indicate slow-growing populations with very large biomass. Overall, the annual total CO(2) incorporation in Lake Cisó was 220 g C m(-2). Most of the CO(2) incorporation, however, was due to the chemolithoautotrophic guild (61% during holomixis and 56% during stratification), followed by the anoxygenic phototrophic guild (35 and 19%, respectively) and the oxygenic phototrophs (4 and 25%, respectively), making dark carbon fixation the key process in the autotrophic metabolism of the lake.
The microzonation of O(2) respiration, H(2)S oxidation, and SO(4) reduction in aerobic trickling-filter biofilms was studied by measuring concentration profiles at high spatial resolution (25 to 100 mum) with microsensors for O(2), S, and pH. Specific reaction rates were calculated from measured concentration profiles by using a simple one-dimensional diffusion reaction model. The importance of electron acceptor and electron donor availability for the microzonation of respiratory processes and their reaction rates was investigated. Oxygen respiration was found in the upper 0.2 to 0.4 mm of the biofilm, whereas sulfate reduction occurred in deeper, anoxic parts of the biofilm. Sulfate reduction accounted for up to 50% of the total mineralization of organic carbon in the biofilms. All H(2)S produced from sulfate reduction was reoxidized by O(2) in a narrow reaction zone, and no H(2)S escaped to the overlying water. Turnover times of H(2)S and O(2) in the reaction zone were only a few seconds owing to rapid bacterial H(2)S oxidation. Anaerobic H(2)S oxidation with NO(3) could be induced by addition of nitrate to the medium. Total sulfate reduction rates increased when the availability of SO(4) or organic substrate increased as a result of deepening of the sulfate reduction zone or an increase in the sulfate reduction intensity, respectively.
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