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Utilization of maltose, isomaltose, and panose in the l-lysine-producing model strain. a Accumulation of l-lysine in the l-lysine production medium supplemented with glucose or glucose combined with maltose, isomaltose, and panose at the end of fermentation. b Residual maltose, isomaltose, and panose in the culture broth at the end of fermentation. Values are the means of more than three independent samples. SE bars represent the standard error of the mean calculated with Excel software. WC196LC (pCABD2) harboring the empty vector plasmids, pTVW229 and pMW219-Δplac (empty vector); WC196LC (pCABD2) harboring the glvA-expressing and glvC-expressing plasmids, pTWV229-self-glvA-Fw and pMW219-ΔPlac-Ptac4075-glvC (glvAC); N.D. not detected, NA no addition
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Industrial glucose feedstock prepared by enzymatic digestion of starch typically contains significant amounts of disaccharides such as maltose and isomaltose and trisaccharides such as maltotriose and panose. Maltose and maltosaccharides can be utilized in Escherichia coli fermentation using industrial glucose feedstock because there is an intrinsi...
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As a demonstration that second order nonlinear optical microscopy is a powerful tool for rice grain science, we observed second-harmonic generation (SHG) images of amylose-free glutinous rice and amylose-containing non-glutinous rice grains. The images obtained from SHG microscopy and photographs of the iodine-stained starch granules indicate that...
Citations
... Additionally, the L-Lys-producing strain E. coli WC196LC (pCABD2) was developed, expressing the phospho-α-glucosidase gene glvA and phosphoenolpyruvate-dependent maltose phosphotransferase system subunit gene glvC from Bacillus subtilis 168, to facilitate the efficient utilization of isomaltose and panose in industrial glucose feedstocks. The engineered strain increased L-Lys yield by 27.7% at a titer of 7 g/L from maltose, isomaltose, and panose [182]. A screened C. glutamicum XQ-8 strain produced L-Lys at a titer of 97.6 g/L, with low glucose consumption. ...
The phosphoenol pyruvate–oxaloacetate–pyruvate-derived amino acids (POP-AAs) comprise native intermediates in cellular metabolism, within which the phosphoenol pyruvate–oxaloacetate–pyruvate (POP) node is the switch point among the major metabolic pathways existing in most living organisms. POP-AAs have widespread applications in the nutrition, food, and pharmaceutical industries. These amino acids have been predominantly produced in Escherichia coli and Corynebacterium glutamicum through microbial fermentation. With the rapid increase in market requirements, along with the global food shortage situation, the industrial production capacity of these two bacteria has encountered two bottlenecks: low product conversion efficiency and high cost of raw materials. Aiming to push forward the update and upgrade of engineered strains with higher yield and productivity, this paper presents a comprehensive summarization of the fundamental strategy of metabolic engineering techniques around phosphoenol pyruvate–oxaloacetate–pyruvate node for POP-AA production, including L-tryptophan, L-tyrosine, L-phenylalanine, L-valine, L-lysine, L-threonine, and L-isoleucine. Novel heterologous routes and regulation methods regarding the carbon flux redistribution in the POP node and the formation of amino acids should be taken into consideration to improve POP-AA production to approach maximum theoretical values. Furthermore, an outlook for future strategies of low-cost feedstock and energy utilization for developing amino acid overproducers is proposed.
... Isomaltose has been studied as an alternative sweetener, prebiotic, potential therapeutic for health issues such as constipation and similar digestive problems, a potential marker for macular degeneration, and for increased conversion efficiency of oligosaccharides containing α-1,6 mixed linkages (Sanz et al. 2005;Harrion et al. 2007;Yen et al. 2011;Abe et al. 2017;Luo et al. 2017;Fatoki et al. 2018). The human gut has only slight capacity for isomaltose hydrolysis and absorption, which allows this α-glucoside to have a reduced glycemic index when compared to more readily absorbed carbohydrates (Ang and Linn 2014). ...
... Typically, starch is degraded using α-amylases which cleave α-1,4 glycosidic bonds and release glucose, maltooligosaccharides, and α-1,6 isomaltose (Gopinath et al. 2017). Recently, isomaltose and isomaltooligosaccharides (IMOs) have gained interest as potential prebiotics and alternative sweeteners (Sanz et al. 2005;Harrion et al. 2007;Yen et al. 2011;Abe et al. 2017;Luo et al. 2017;Fatoki et al. 2018). IMO-producing enzymes are largely described as glycoside hydrolases which also possess transferase activities (Lombard et al. 2014). ...
... As has been previously observed with increased trehalose consumption, there may be unforeseen consequences regarding pathogenicity and virulence of gut bacteria (Dalwai et al. 2006;Collins et al. 2018). From an industrial standpoint, engineering organisms to generate these metabolites requires a complete understanding of their production, transport, and degradation (Keasling 2010;Abe et al. 2017). Therefore, a complete understanding of both biosynthesis and degradation is integral from an industrial standpoint. ...
In a competitive microbial environment, nutrient acquisition is a major contributor to the survival of any individual bacterial species, and the ability to access uncommon energy sources can provide a fitness advantage. One set of soluble carbohydrates that have attracted increased attention for use in biotechnology and biomedicine is the α-diglucosides. Maltose is the most well-studied member of this class; however, the remaining four less common α-diglucosides (trehalose, kojibiose, nigerose, and isomaltose) are increasingly used in processed food and fermented beverages. The consumption of trehalose has recently been shown to be a contributing factor in gut microbiome disease as certain pathogens are using α-diglucosides to outcompete native gut flora. Kojibiose and nigerose have also been examined as potential prebiotics and alternative sweeteners for a variety of foods. Compared to the study of maltose metabolism, our understanding of the synthesis and degradation of uncommon α-diglucosides is lacking, and several fundamental questions remain unanswered, particularly with regard to the regulation of bacterial metabolism for α-diglucosides. Therefore, this minireview attempts to provide a focused analysis of uncommon α-diglucoside metabolism in bacteria and suggests some future directions for this research area that could potentially accelerate biotechnology and biomedicine developments.
Key points
• α-diglucosides are increasingly important but understudied bacterial metabolites.
•Kinetically superior α-diglucoside enzymes require few amino acid substitutions.
•In vivo studies are required to realize the biotechnology potential of α-diglucosides.
... Fermentation production of sulfur-containing amino acids Transporters of raw materials and metabolites are usually important for amino acid production (31), including the production of sulfur-containing amino acids; therefore, they could be important targets for genetic engineering of amino acidproducing strains. ...
Here, proteins involved in sulfur-containing amino acid uptake in Escherichia coli strains were investigated with the aim of applying the findings in fermentative amino acid production. A search of genes in an l-methionine auxotrophic strain library suggested YecSC as the putative transporter of l-cystathionine. l-Methionine production increased by 15% after amplification of yecSC in producer strains. A candidate protein responsible for l-cysteine uptake was also found by experimentation with multicopy suppressor E. coli strains that recovered from growth defects caused by l-cysteine auxotrophy. Based on the results of an uptake assay, growth using l-cysteine as a sole sulfur source, and sensitivity to l-cysteine toxicity, we proposed that YeaN is an l-cysteine transporter. l-Cysteine production increased by 50% as a result of disrupting yeaN in producer strain. The study of amino acid transporters is valuable to industrialized amino acid production and also sheds light on the role of these transporters in sulfur assimilation.
... Moreover, proteins that uptake these carbon sources, regardless of the PTS system, are represented (e.g., MalE, IMGlc/Fru, and CscB) [23]. Figure 3 also illustrates some techniques that enables the use of alternative carbon sources: (1) amylaceous biomass, mainly compounds derived from incomplete starch saccharification (malE and glvC gene expression for maltose uptake and for isomaltose and panose uptake, respectively) [8,[24][25][26]; (2) marine phytobiomass (by means of ToaA, a membrane protein with oligoalginate transport function) [27]; (3) food-processing residues, in particular shrimp shells (from NagE and ManXYZ proteins, which allow the uptake of hydrolyzed chitin) [28,29] and whey (uptake of lactose and galactose by LacY protein) [30]; (4) lignocellulosic biomass (XylE and AraE proteins, for xylose and arabinose transport) [31]; and (5) industrial wastes such as glycerol (GlpF, GlpK, and GlpD proteins) [32]. ...
L-lysine is an essential amino acid used in various industrial sectors but mainly in food and animal feed. Intense research has been directed toward increasing its productivity. This literature review presents the state of the art and patent landscape of the industrial production of L-lysine, with a focus on the strain development and fermentation technologies, through geographic, social, and chronological analysis, using the text mining technique. The geographic analysis showed a greater tendency for countries with industrial plants with large production capacity to submit patents or publish articles, while the social analysis reflected the close relationship between educational units and companies. The technologies of each document were divided into optimization of fermentation parameters, conventional mutation, and genetic engineering. Corynebacterium glutamicum and Escherichia coli present the most attractive industrial phenotypes , and their cultivation occurs mainly in fed-batch processes with control parameters carefully selected to enhance metabolism. These strains are generally modified by conventional approaches (e.g., mutagenesis and selection of auxotrophic and/or regulatory mutants) or by genetic engineering technologies. The combination of both these approaches enables genomic breeding and the construction of strains with industrial potential, capable of accumulating more than 120 g/L of L-lysine. From the analysis of these approaches, we developed a descriptive flow of substrate uptake, amino acid metabolism, and mechanisms of excretion of a lysine-producing model cell. It is expected that the various mechanisms of L-lysine production, here shown and described, will become a guide that aids in increasing amino acid productivity without interfering with the strain stability. ARTICLE HISTORY
... Previous study has shown that natural and engineered bacteria can effectively assimilate isomaltose by implication of phospho-αglucosidase and phosphoenolpyruvatedependent maltose phosphotransferase system (PEP:PTS), leading to the formation of isomaltose-6-phosphate [16,17]. In Streptomyces coelicolor, fructose, N-acetylglucosamine, and possibly two other carbohydrates are transported by the phosphotransferase system [18,19]. ...
Aim: To validate the empirical functions of isomaltose and proposed its fates in metabolism using
computational analysis.
Place and Duration of Study: This work was carried out at the Department of Biochemistry at the
Federal University of Technology Akure Nigeria in 2017.
Methodology: We make use of text mining of experimental articles on isomaltose, predicted the
potential targets using Swisstargetprediction server, and the Swisssimilarity server was used for
drug similarity analysis.
Results: Isomaltose exhibits antimicrobial activity, biodegradability, non-toxic, and find its use in
food, biochemistry and pharmaceutical industries as a prebiotic molecule, precursor metabolite and
potent medicine respectively. Isomaltose possibly has a lower glycemic index, with the fate that
implicated the production of diglucosamine, by the help of specific aminotransferase, and that there
is a possibility of biosynthesis of secondary metabolites through isomaltose pathway.
Conclusion: This study provides the future areas of research and application of isomaltose.
There is a growing demand to develop biocontainment strategies that prevent unintended proliferation of genetically modified organisms in the open environment. We found that the hypophosphite (H3PO2, HPt) transporter HtxBCDE from Pseudomonas stutzeri WM88 was also capable of transporting phosphite (H3PO3, Pt) but not phosphate (H3PO4, Pi), suggesting the potential for engineering a Pt/HPt-dependent bacterial strain as a biocontainment strategy. We disrupted all Pi and organic Pi transporters in an Escherichia coli strain expressing HtxABCDE and a Pt dehydrogenase, leaving Pt/HPt uptake and oxidation as the only means to obtain Pi. Challenge on non-permissive growth medium revealed that no escape mutants appeared for at least 21 days with a detection limit of 1.94 × 10−13 per colony forming unit. This represents, to the best of our knowledge, the lowest escape frequency among reported strategies. Since Pt/HPt are ecologically rare and not available in amounts sufficient for the growth of the Pt/HPt-dependent bacteria, this strategy offers a reliable and practical method for biocontainment.
