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Actinomycetes are a complex group of bacteria present in a wide variety of environments, either as dormant spores or actively growing. Some actinomycetes produce two potent terpenoids (geosmin and 2-methylisoborneol (MIB)) and pyrazines, common causes of drinking water off flavours, and have been implicated in taste and odour episodes. However, iso...
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... chlorine, earthy/musty odours are the second most common type of reported T/O (Suffett, 1996), and most often caused by the metabolites geosmin and MIB (Wnorowski, 1992 and many others). As observed above, some actinomycetes (notably Streptomyces) produce one or both of these terpenoids, as well as other musty/earthy smelling metabolites (Table 4). Actinomycetes have been associated with musty/earthy odours in water and fish since the early 1900s (Adams, 1929;Thaysen, 1936). ...Similar publications
Pulp and paper mills are well known for their sharp, sulphurous stack emissions, but the secondary treatment units also can be significant contributors to local odour. This study investigated the source(s) of earthy/musty emissions from a mixed hardwood pulp mill in response to a high local odour. Samples from five sites in the mill over five month...
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... Our results indicated that Proteobacteria, Actinobacteria, Cyanobacteria, and Bacteroidets accounted for 90% of the total microbial community at the phylum level ( Figure 5). This may be related to Proteobacteria, Actinobacteria and Bacteroidetes are all believed to degrade complex organic macromolecules (González et al., 2000;Kirchman, 2002;Zaitlin and Watson, 2006). Previous study showed that Proteobacteria and Actinobacteria were the dominant microbial community in surface water of reservoir which account for more than 50% of the total bacteria (Yu et al., 2014). ...
It is well-known that water quality has great significance on microbial community composition in aquatic environments. In this study, we detected water column indicates the microbial community composition of nine sampling sites over two seasons using Illumina TruSeq sequencing in Songtao Reservoir, Hainan Province, Southmost China. The study indicated that the dominant phylum was Actinobacteria, Proteobacteria, Bacteroidetes, and Cyanobacteria. The diversity parameters showed that the microbial community composition had significant spatiotemporal variations, including the significantly higher Shannon index and Simpson index upstream than those midstream and downstream. Besides, there were significantly higher Chao1 index, Shannon index, and Simpson index in winter than in summer. Principal coordinates analysis (PCoA) showed the microbial structural composition had significant seasonal differences. The results of microbial community composition further revealed that the eutrophication level upstream was higher than that of midstream and downstream. The redundancy analysis (RDA) diagram indicated that the abundance of microbiology species significantly correlated with temperature, total phosphorus, Se, and Ni. Furthermore, the mantel's test showed that the temperature and total phosphorus significantly affected the community composition of archaea and bacteria. Overall, our finding here partially validated our hypothesis that the spatiotemporal variations of microbial community composition are significantly related to nutrients, physicochemical factors and metals, which has been unknown previously in tropical drinking waterbodies. This study substantially contributed to understanding of the composition of microbial community in tropical drinking water reservoirs and the main environmental driving factors in tropical zones. It also provided a reference for the management of reservoir operation to ensure drinking water safe.
... This information is essential for our ability to identify the sources of taste and odor issues in water and differentiate between potential terrestrial and aquatic origins. 1 . The remarkable adaptability of Actinobacteria to thrive in a wide range of ecological settings establishes them as prevalent filamentous microorganisms. ...
Antibiotics are a crucial tool in modern medicine and have saved countless lives by effectively treating a wide range of bacterial infections. The microbial antibiotic have several biotechnological applications viz. agriculture, pharmaceuticals, food preservation, animal nutritions. The diverse array of applications and the various roles of bioactive metabolites produced by Actinomycetes have sparked a growing interest in the exploration of unique and unprecedented Actinomycetes strains. The Actinomycetes from soil ecosystem, marine ecosystem, rhizosphere of plant roots are also known to secrete novel antibiotics. In this context, the main objective of this research is to isolate and screen Actinomycetes strains that are capable of producing highly potent culturable secondary metabolites with novel antibacterial properties. These metabolites can potentially serve as biocontrol agents against Xanthomonas infections in Ricinus communis L., offering uncommon and innovative applications within the field of agriculture. All the Actinomycetes isolates were isolated from Mehsana regions of Gujarat an area of over 4,401 km2, with wide microbial diversity and can serve as a source for promising antibiotics producers. 7 rhizospheric soil samples were collected from various region sites viz. Ranasan, Mansa, Panchot, Gozariya, Kansa, Langhnaj, and Kherva. Total 76 antibiotic producing Actinomycetes isolates were obtained in Primary Screening. Based on the results of primary screening, potential morphologically diverse 3 isolates were selected for antibiotic production in liquid medium. FTIR analysis of three samples revealed distinct bands in the spectra. Sample-1 exhibited O-H (1347 cm^-1) and C-N (1191 cm^-1) groups. Sample-2 displayed O-H (3462 cm^-1), C-O (1043 cm^-1), and C=O (1736 cm^-1) groups. Sample-3 showcased O-H (3466 cm^-1), C=O (1737 cm^-1), C-N (1232 cm^-1), and C-O (1043 cm^-1) groups, providing valuable insights into their chemical compositions. The isolate BNPA72 gave best antibiotic production and was identified as Streptomyces chartreusis by 16 s rRNA gene sequencing method. The isolate Streptomyces chartreusis BNPA72 was able to inhibit the plant pathogen Xanthomonas, hence categorized as Biocontrol agents.
... The water distribution system (pipeline) has been reported as biologically contaminated for several years by epidemiologists and pathologists in Asia and Europe [1,2]. The water is significantly affected by the number of fungi, bacteria, protozoa, actinomycetes and cyanobacteria and these are reported to change the adverse odour and taste of the drinking water distribution system [1][2][3][4][5][6]. The presence of fungi genera in drinking water not only changes the odour and taste but also causes some operational and technological difficulties [3]. ...
... The presence of fungi genera in drinking water not only changes the odour and taste but also causes some operational and technological difficulties [3]. Water contamination by fungal activities can produce mycotoxicity and allergy to human health [4,5]. It can be transmitted or inhaled during the sauna or showering. ...
The water quality in Karachi (Pakistan) is uncertain due to the occurrence of fungi and other microorganisms. A total of twenty-five water samples were collected from public places, educational institutes, hospitals, water supply systems and surface water of the canal of Karachi (Pakistan). The different fungal species including Acremonium sp., Alternaria alternata, Aspergillus flavus, A. fumigatus, A. sulphureus, Cladosporium sp., Fusarium sp., Clonostachys (Gliocladium) sp., Macrophomina phaseolina, Mucor racemosus, Paecilomyces sp. Penicillium chrysogenum, P. citrinum, P. commune, P. expansum, Rhizoctonia sp. and Stachybotrys sp. were isolated from these drinking water samples. However, the bacteria, microalgae and some other microorganisms were present in low concentrations. The reason for fungi infection and production of mycotoxicity depends upon various factors and the availability of their nutrients in filtration plants. The major threats to human health are fungal mycotoxicity which is responsible for carcinogenic and other lethal diseases. Mostly, the genus Aspergillus was dominated and isolated with a maximum of 88–98% of occurrence in the different samples of drinking water by the direct plate-spread method. For the control of fungi, various Physico-chemical coagulation treatments were used, but Potassium alum, clay pot, and hot water treatment disinfected effectively 69–70% removal of the fungi and its spore or mycelia from the water. In addition, it is concluded that drinking water purifications such as chlorination, filtration and lime did not eliminate thermophilic fungal spores or mycelia including Penicillium, Paecilomyces and Mucor from the water.
... (Fig. 2e-g). Microorganisms, including fungi and actinomycetes, particularly Streptomyces found in soils, have been recognised as major contributors to the production of odour compounds like geosmin and 2-MIB in both aquatic and terrestrial environments [13,40,49]. Therefore, we hypothesise that the primary sources of geosmin in the riverine region of Xin'anjiang Reservoir were actinomycetes and microorganisms, which can utilise bacillariophyta as an organic carbon source. ...
2-Methylisoborneol (2-MIB) and geosmin are compounds released by algae that significantly degrade reservoir water quality, posing a threat to both the safety of drinking water and the quality of aquatic products sourced from these environments. However, few studies have explored how enhanced thermal stratification affects the occurrence and regulation of odorants in large drinking water reservoirs. Through systematic monitoring and investigation of Xin'anjiang Reservoir, we found that enhanced thermal stratification promotes filamentous cyanobacteria, particularly Leptolyngbya sp., as the primary contributor to 2-MIB production within the 1-10 m layer of the water column. The highest 2-MIB concentration, 92.5 ng/L, was recorded in the riverine region, which was 2.54 and 14.52 times higher than that in the transitional and central parts of the reservoir, respectively. Temperature indirectly impacted algal growth and odorant production by modulating TN/TP ratios. Geosmin concentration responded rapidly to relatively low TN/TP ratios (< 25). Our findings suggest that phosphorus control in estuaries should be enhanced during thermal stratification period. In summary, our study provides valuable insights to inform pragmatic water intake strategies and the distribution and release of odorants caused by thermal stratification. This is particularly relevant in the context of future global warming and extremely high temperatures during the warm season.
... Zou et al. (Zou et al. 2016) identified that the primary compounds responsible for the T&O problem in bluegreen algae growth are geosmin (GSM), 2-methylisoborneol (2-MIB), 2-isobutyl-3-methoxy pyrazine (2-IBMP), 2,3,6-trichloroanisole (2,3,6-TCA), and 2,4,6-trichloroanisole (2,4,6-TCA). Although many organisms possess the potential to produce GSM and 2-MIB, actinomycetes and cyanobacteria are the most likely culprits for the earthy/ musty odorants in water sources (Izaguirre and Taylor 2004;Klausen et al. 2005;Suffet et al. 1999;Zaitlin and Watson 2006). GSM and 2-MIB are the main compounds responsible for the poor taste and odor in water (Kakimoto et al. 2014). ...
Contamination by odor substances such as geosmin (GSM) and 2-methylisoborneol (2-MIB) was examined in the cultured water from aquaculture farming in the region of the Hongze Lake in 2022, and some factors influencing residual levels of them in the water were analyzed. Geographically, high concentrations of GSM were located mainly in the north and northeast culture areas of the lake, while those of 2-MIB were found in the northeast and southwest. Analysis of the water in the enclosure culture revealed significant differences in the concentrations of GSM and 2-MIB among the cultured species. The mean concentrations of GSM in culture water were ranked in the order: crab > the four major Chinese carps > silver and bighead carp, and silver and bighead carp > crab > the four major Chinese carps for 2-MIB. The concentration of GSM was significantly higher at 38.99 ± 18.93 ng/L in crab culture water compared to other fish culture water. Significant differences were observed in GSM concentrations between crab enclosure culture and pond culture, while 2-MIB levels were comparable. These findings suggest that cultural management practices significantly affect the generation of odor substances. The taste and odor (T&O) assessment revealed that the residual levels of GSM and 2-MIB in most samples were below the odor threshold concentrations (OTCs), although high levels of GSM and 2-MIB in all water bodies were at 30.9% and 27.5%, respectively. Compared with the corresponding data from other places and the regulation guidelines of Japan, USA, and China, the region in the Hongze Lake is generally classified as a slightly T&O area, capable of supporting the aquaculture production scale.
... Both are terpenoids and are synthesized from linear isoprene diphosphate precursors with various chain lengths (Pham et al., 2020). They have also been reported to be produced (synthesized and secreted) as secondary metabolites by different types of cyanobacteria (Izaguirre et al., 1982;Carmichael, 2001;Pham et al., 2020), but other studies have shown actinomycetes, proteobacteria, myxobacteria and some fungi to be geosmin producers (Zaitlin and Watson, 2006;John et al., 2018). ...
The present study aimed to propose a new cause of odorous compounds release, i.e., the presence of antibiotics in water bodies and its toxicity to cyanobacteria, known to be the main producer of geosmin (GEO) and 2-methylisoborneol (2-MIB). Therefore, a literature review was carried out regarding the problems caused by antibiotics in aquatic environment, including cyanobacterial blooms and GEO and 2-MIB release. In addition, a bibliometric analysis was performed using the VOSviewer software based on the results obtained from the Web of Science (WOS) database. This review aims to build a scientific understanding of the problem, presenting interesting points that converge with the proposed association. It is worth mentioning that no work has been found in the literature that has proposed this relationship. Thus, based on the bibliographic survey, observations and information acquired in recent years about cyanobacterial blooms and environmental contamination by pharmaceutical drugs, one of the main causes of an earthy and musty flavour and odour in a drinking water supply is the toxicity imposed by the presence of antibiotics in aquatic environments on cyanobacteria.
... Many microorganisms, including cyanobacteria, actinomycetes, and certain fungi, produce malodorous compounds [1]. In water reservoirs, several species of cyanobacteria produce earthy-or musty-smelling compounds as secondary metabolites [2][3][4]. ...
Cyanobacteria can exist in water resources and produce odorants. 2-Methylisoborneol (2-MIB) and geosmin are the main odorant compounds affecting the drinking water quality in reservoirs. In this study, encoding genes 2-MIB (mic, monoterpene cyclase) and geosmin (geo, putative geosmin synthase) were investigated using newly developed primers for quantitative PCR (qPCR). Gene copy numbers were compared to 2-MIB/geosmin concentrations and cyanobacterial cell abundance. Samples were collected between July and October 2020, from four drinking water sites in South Korea. The results showed similar trends in three parameters, although the changes in the 2-MIB/geosmin concentrations followed the changes in the mic/geo copy numbers more closely than the cyanobacterial cell abundances. The number of odorant gene copies decreased from upstream to downstream. Regression analysis revealed a strong positive linear correlation between gene copy number and odorant concentration for mic (R2 = 0.8478) and geo (R2 = 0.601). In the analysis of several environmental parameters, only water temperature was positively correlated with both mic and geo. Our results demonstrated the feasibility of monitoring 2-MIB/geosmin occurrence using qPCR of their respective synthase genes. Odorant-producing, gene-based qPCR monitoring studies may contribute to improving drinking water quality management.
... Additionally, the free-living Ilumatobacteraceae are part of particle-associated bacterial communities in aquatic ecosystems and play important roles in organic matter decomposition [47]. The high abundance of these families in the water samples and their relatively low abundance in the sediment and soil samples imply that they are capable of active growth and reproduction in aquatic environments, rather than being simply transients from terrestrial environments [48]. ...
Culture-independent and culture-dependent approaches were employed to investigate the taxonomic diversity and biosynthetic gene cluster potential of Actinomycetota in the Mekong River. Through 16S rRNA gene metabarcoding, 21,103 OTUs were revealed to represent 190 genera and at least 595 species of Actinomycetota, including putatively novel taxa. Conventional and in situ cultivation (IC) methods provided 75 Actinomycetota isolates representing 72 species from 21 genera. Of these, 45 species in 4 genera were new to the Thailand Bioresource Research Center (TBRC), a collection of 20,079 Actinomycetota strains from 660 species. Applying both culture-independent and culture-dependent approaches to the same sample revealed greater diversity among the Actinomycetota in the Mekong River than one approach alone.
... In addition, most cyanobacteria species cause odor problems, such as the presence of various volatile organic compounds (VOCs), such as geosmin (Lee et al., 2017), often produced by Anabaena, Lyngbya, Oscilatoria, Planktothrix, Microcystis, and Symploca (Conradie et al., 2008;Smith et al., 2008). In addition to geosmin, 2-methylisoborneol (MIB) is another common odor-generated product by cyanobacteria (Zaitlin and Watson, 2006), including Oscillatoria and Aphanizomenon (Conradie et al., 2008;Lee et al., 2017). Drobac et al. (2016) found that cyanobacterial hazard in several fishponds in Serbia caused histopathological damage to fish liver, kidney, gills, intestines and muscle tissues. ...
Cyanobacteria blooms in aquaculture ponds harm the harvesting of aquatic animals and threaten human health. Therefore, it is crucial to identify key drivers and develop methods to predict cyanobacteria blooms in aquaculture water management. In this study, we analyzed monitoring data from 331 aquaculture ponds in central China and developed two machine learning models-the least absolute shrinkage and selection operator (LASSO) regression model and the random forest (RF) model-to predict cyanobacterial abundance by identifying the key drivers. Simulation results demonstrated that both machine learning models are feasible for predicting cyano-bacterial abundance in aquaculture ponds. The LASSO model (R 2 = 0.918, MSE = 0.354) outperformed the RF model (R 2 = 0.798, MSE = 0.875) in predicting cyanobacteria abundance. Farmers with well-equipped aquaculture ponds that have abundant water monitoring data can use the nine environmental variables identified by the LASSO model as an operational solution to accurately predict cyanobacteria abundance. For crude ponds with limited monitoring data, the three environmental variables identified by the RF model provide a convenient solution for useful cyanobacteria prediction. Our findings revealed that chemical oxygen demand (COD) and total organic carbon (TOC) were the two most important predictors in both models, indicating that organic carbon concentration had a close relationship with cyanobacteria growth and should be considered a key metric in water monitoring and pond management of these aquaculture ponds. We suggest that monitoring of organic carbon coupled with phosphorus reduction in feed usage can be an effective management approach for cyano-bacteria prevention and to maintain a healthy ecological state in aquaculture ponds.
... Widespread musty odor events caused by MIB have been increasingly reported in recent decades, raising considerable public attention (Devi et al., 2021;Lee et al., 2017). Cyanobacteria (Lee et al., 2017) and actinomycetes (Zaitlin and Watson, 2006;Zuo et al., 2010) have been widely accepted as the main MIB producers, although the dominant source for a specific water body is sometimes controversial. Previous studies have revealed that the cyclic nucleotide-binding protein genes (cnb A and cnb B), methyl transferase gene (mtf), and MIB cyclase gene (mic) are associated with MIB biosynthesis (Giglio et al., 2011;Komatsu et al., 2008). ...
Cellular 2-methylisoborneol (MIB) yield of cyanobacteria varies under different conditions according to culture studies and field investigations, the causal mechanism remains unclear and results in ineffective MIB prediction. Through an intensive field survey during an MIB episode produced by Pseudanabaena cinerea in QCS reservoir, we demonstrated that MIB synthesis (mic) gene abundance (DNA) and expression (RNA) might be useful as parameters for early warning of MIB production. It was found that the abundance of mic DNA and RNA peaked ahead of MIB concentrations by 10 and 7 days, respectively. In addition, the RNA abundance (R2 = 0.45, p < 0.01) showed a slightly higher correlation with MIB compared to DNA abundance (R2 = 0.37, p < 0.01), suggesting that the conditions for the growth of Pseudanabaena cinerea might be slightly different from those for mic gene expression, which was verified by a culture experiment. The highest cell growth was obtained under 36 μmol photons m−2 s−1, while the highest cellular MIB yield and mic gene expression level were obtained under 85 μmol photons m−2 s−1. Our results clearly supported that light intensity was the virtual regulator governing the mic gene expression within the controlled culture experiment and the actual MIB episode in the reservoir. Besides these results, we developed an early warning model using mic gene abundance as an indicator of MIB episodes, which was verified in two other reservoirs. Our findings highlight the effect of light intensity on mic gene expression and MIB synthesis and provide an early warning tool targeting MIB episode prediction, which therefore should be of importance for source water authorities.
