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International Journal of Molecular... Nov 2021Bacterial cellulose (BC) is recognized as a multifaceted, versatile biomaterial with abundant applications. Groups of microorganisms such as bacteria are accountable for... (Review)
Review
Bacterial cellulose (BC) is recognized as a multifaceted, versatile biomaterial with abundant applications. Groups of microorganisms such as bacteria are accountable for BC synthesis through static or agitated fermentation processes in the presence of competent media. In comparison to static cultivation, agitated cultivation provides the maximum yield of the BC. A pure cellulose BC can positively interact with hydrophilic or hydrophobic biopolymers while being used in the biomedical domain. From the last two decades, the reinforcement of biopolymer-based biocomposites and its applicability with BC have increased in the research field. The harmony of hydrophobic biopolymers can be reduced due to the high moisture content of BC in comparison to hydrophilic biopolymers. Mechanical properties are the important parameters not only in producing green composite but also in dealing with tissue engineering, medical implants, and biofilm. The wide requisition of BC in medical as well as industrial fields has warranted the scaling up of the production of BC with added economy. This review provides a detailed overview of the production and properties of BC and several parameters affecting the production of BC and its biocomposites, elucidating their antimicrobial and antibiofilm efficacy with an insight to highlight their therapeutic potential.
Topics: Anti-Bacterial Agents; Biofilms; Biopolymers; Cellulose; Escherichia coli; Gluconacetobacter xylinus; Hydrophobic and Hydrophilic Interactions; Nanocomposites; Staphylococcus aureus
PubMed: 34884787
DOI: 10.3390/ijms222312984 -
International Journal of Systematic and... Nov 2020Two Gram-stain-negative, facultative anaerobic, chemoheterotrophic, pink-coloured, rod-shaped and non-motile bacterial strains, PAMC 26568 and PAMC 26569, were isolated...
Two Gram-stain-negative, facultative anaerobic, chemoheterotrophic, pink-coloured, rod-shaped and non-motile bacterial strains, PAMC 26568 and PAMC 26569, were isolated from an Antarctic lichen. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strains PAMC 26568 and PAMC 26569 belong to the family and the most closely related species are (96.1 %), (95.9 %) and (95.7 %). Phylogenomic and genomic relatedness analyses showed that strains PAMC 26568 and PAMC 26569 are clearly distinguished from other genera in the family by average nucleotide identity values (<72.8 %) and the genome-to-genome distance values (<22.5 %). Genomic analysis revealed that strains PAMC 26568 and PAMC 26569 do not contain genes involved in atmospheric nitrogen fixation and utilization of sole carbon compounds such as methane and methanol. Instead, strains PAMC 26568 and PAMC 26569 possess genes to utilize nitrate and nitrite and certain monosaccharides and disaccharides. The major fatty acids (>10 %) are summed feature 8 (C ω7 and/or C ω6; 40.3-40.4 %), C 2OH (22.7-23.7 %) and summed feature 2 (C 3OH and/or C iso I; 12.0 % in PAMC 26568). The major respiratory quinone is Q-10. The genomic DNA G+C content of PAMC 26568 and PAMC 26569 is 64.6 %. Their distinct phylogenetic position and some physiological characteristics distinguish strains PAMC 26568 and PAMC 26569 from other genera in the family supporting the proposal of gen. nov., with the type species sp. nov. (type strain, PAMC 26569=KCCM 43315=JCM 33604).
Topics: Acetobacteraceae; Antarctic Regions; Bacterial Typing Techniques; Base Composition; DNA, Bacterial; Fatty Acids; Lichens; Phylogeny; Pigmentation; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Ubiquinone
PubMed: 33034550
DOI: 10.1099/ijsem.0.004495 -
World Journal of Microbiology &... Jun 2022Gluconobacter oxydans is a well-known acetic acid bacterium that has long been applied in the biotechnological industry. Its extraordinary capacity to oxidize a variety... (Review)
Review
Gluconobacter oxydans is a well-known acetic acid bacterium that has long been applied in the biotechnological industry. Its extraordinary capacity to oxidize a variety of sugars, polyols, and alcohols into acids, aldehydes, and ketones is advantageous for the production of valuable compounds. Relevant G. oxydans industrial applications are in the manufacture of L-ascorbic acid (vitamin C), miglitol, gluconic acid and its derivatives, and dihydroxyacetone. Increasing efforts on improving these processes have been made in the last few years, especially by applying metabolic engineering. Thereby, a series of genes have been targeted to construct powerful recombinant strains to be used in optimized fermentation. Furthermore, low-cost feedstocks, mostly agro-industrial wastes or byproducts, have been investigated, to reduce processing costs and improve the sustainability of G. oxydans bioprocess. Nonetheless, further research is required mainly to make these raw materials feasible at the industrial scale. The current shortage of suitable genetic tools for metabolic engineering modifications in G. oxydans is another challenge to be overcome. This paper aims to give an overview of the most relevant industrial G. oxydans processes and the current strategies developed for their improvement.
Topics: Acetic Acid; Biotechnology; Fermentation; Gluconobacter oxydans; Metabolic Engineering
PubMed: 35688964
DOI: 10.1007/s11274-022-03310-8 -
Applied and Environmental Microbiology Dec 2022Plant growth-promoting (PGP) bacteria are important to the development of sustainable agricultural systems. PGP microbes that fix atmospheric nitrogen (diazotrophs)...
Plant growth-promoting (PGP) bacteria are important to the development of sustainable agricultural systems. PGP microbes that fix atmospheric nitrogen (diazotrophs) could minimize the application of industrially derived fertilizers and function as a biofertilizer. The bacterium Gluconacetobacter diazotrophicus is a nitrogen-fixing PGP microbe originally discovered in association with sugarcane plants, where it functions as an endophyte. It also forms endophyte associations with a range of other agriculturally relevant crop plants. G. diazotrophicus requires microaerobic conditions for diazotrophic growth. We generated a transposon library for G. diazotrophicus and cultured the library under various growth conditions and culture medium compositions to measure fitness defects associated with individual transposon inserts (transposon insertion sequencing [Tn-seq]). Using this library, we probed more than 3,200 genes and ascertained the importance of various genes for diazotrophic growth of this microaerobic endophyte. We also identified a set of essential genes. Our results demonstrate a succinct set of genes involved in diazotrophic growth for G. diazotrophicus, with a lower degree of redundancy than what is found in other model diazotrophs. The results will serve as a valuable resource for those interested in biological nitrogen fixation and will establish a baseline data set for plant free growth, which could complement future studies related to the endophyte relationship.
Topics: Symbiosis; Gluconacetobacter; Nitrogen Fixation; Nitrogen
PubMed: 36374093
DOI: 10.1128/aem.01241-22 -
Science (New York, N.Y.) Apr 2024The commensal microbiota of the mosquito gut plays a complex role in determining the vector competence for arboviruses. In this study, we identified a bacterium from the...
The commensal microbiota of the mosquito gut plays a complex role in determining the vector competence for arboviruses. In this study, we identified a bacterium from the gut of field mosquitoes named sp. YN46 (YN46) that rendered mosquitoes refractory to infection with dengue and Zika viruses. Inoculation of 1.6 × 10 colony forming units (CFUs) of YN46 into mosquitoes effectively prevents viral infection. Mechanistically, this bacterium secretes glucose dehydrogenase (GDH), which acidifies the gut lumen of fed mosquitoes, causing irreversible conformational changes in the flavivirus envelope protein that prevent viral entry into cells. In semifield conditions, YN46 exhibits effective transstadial transmission in field mosquitoes, which blocks transmission of dengue virus by newly emerged adult mosquitoes. The prevalence of YN46 is greater in mosquitoes from low-dengue areas (52.9 to ~91.7%) than in those from dengue-endemic regions (0 to ~6.7%). YN46 may offer an effective and safe lead for flavivirus biocontrol.
Topics: Animals; Aedes; Symbiosis; Dengue Virus; Mosquito Vectors; Zika Virus; Dengue; Gastrointestinal Microbiome; Acetobacteraceae; Female; Viral Envelope Proteins; Flavivirus; Zika Virus Infection
PubMed: 38669573
DOI: 10.1126/science.adn9524 -
Bioscience, Biotechnology, and... Apr 2024Gluconobacter strains perform incomplete oxidation of various sugars and alcohols, employing regio- and stereoselective membrane-bound dehydrogenases oriented toward the... (Review)
Review
Gluconobacter strains perform incomplete oxidation of various sugars and alcohols, employing regio- and stereoselective membrane-bound dehydrogenases oriented toward the periplasmic space. This oxidative fermentation process is utilized industrially. The ketogluconate production pathway, characteristic of these strains, begins with the conversion of d-glucose to d-gluconate, which then diverges and splits into 2 pathways producing 5-keto-d-gluconate and 2-keto-d-gluconate and subsequently 2,5-diketo-d-gluconate. These transformations are facilitated by membrane-bound d-glucose dehydrogenase, glycerol dehydrogenase, d-gluconate dehydrogenase, and 2-keto-d-gluconate dehydrogenase. The variance in end products across Gluconobacter strains stems from the diversity of enzymes and their activities. This review synthesizes biochemical and genetic knowledge with biotechnological applications, highlighting recent advances in metabolic engineering and the development of an efficient production process focusing on enzymes relevant to the ketogluconate production pathway in Gluconobacter strains.
Topics: Gluconates; Gluconobacter; Biotechnology; Fermentation; Metabolic Engineering; Glucose; Glucose 1-Dehydrogenase; Sugar Alcohol Dehydrogenases
PubMed: 38323387
DOI: 10.1093/bbb/zbae013 -
MicrobiologyOpen Dec 2019In the present work, glycerol biotransformation using Gluconobacter strains was studied with a process intensification perspective that facilitated the development of a...
In the present work, glycerol biotransformation using Gluconobacter strains was studied with a process intensification perspective that facilitated the development of a cleaner and more efficient technology from those previously reported. Starting from the industrial by-product, crude glycerol, resting cells of Gluconobacter frateurii and Gluconobacter oxydans were able to convert glycerol under batch reactor conditions in water with no other additive but for the substrate. The study of strains, biomass:solution ratio, pH, growth stage, and simplification of media composition in crude glycerol bioconversions facilitated productivities of glyceric acid of 0.03 g/L.h and 2.07 g/L.h (71.5 g/g % pure by NMR) of dihydroxyacetone (DHA). Productivities surmounted recent reported fermentative bioconversions of crude glycerol and were unprecedented for the use of cell suspended solely in water. This work proposes a novel approach that allows higher productivities, cleaner production, and reduction in water and energy consumption, and demonstrates the applicability of the proposed approach.
Topics: Biotransformation; Carbohydrate Metabolism; Chromatography, High Pressure Liquid; Dihydroxyacetone; Gluconobacter; Glyceric Acids; Glycerol; Kinetics; Magnetic Resonance Spectroscopy
PubMed: 31532065
DOI: 10.1002/mbo3.926 -
Applied and Environmental Microbiology Sep 2022In industrial production, the precursor of l-ascorbic acid (L-AA, also referred to as vitamin C), 2-keto-l-gulonic acid (2-KLG), is mainly produced using a classic... (Review)
Review
In industrial production, the precursor of l-ascorbic acid (L-AA, also referred to as vitamin C), 2-keto-l-gulonic acid (2-KLG), is mainly produced using a classic two-step fermentation process performed by Gluconobacter oxydans, Bacillus megaterium, and Ketogulonicigenium vulgare. In the second step of the two-step fermentation process, the microbial consortium of and B. megaterium is used to achieve 2-KLG production. can transform l-sorbose to 2-KLG, but the yield of 2-KLG is much lower in the monoculture than in the coculture fermentation system. The relationship between the two strains is too diverse to analyze and has been a hot topic in the field of vitamin C fermentation. With the development of omics technology, the relationships between the two strains are well explained; nevertheless, the cell-cell communication is unclear. In this review, based on current omics results, the interactions between the two strains are summarized, and the potential cell-cell communications between the two strains are discussed, which will shed a light on the further understanding of synthetic consortia.
Topics: Ascorbic Acid; Fermentation; Gluconobacter oxydans; Microbial Interactions; Rhodobacteraceae; Sorbose; Sugar Acids; Vitamins
PubMed: 36073939
DOI: 10.1128/aem.01212-22 -
Biotechnology and Bioengineering Aug 2019Adaptive laboratory evolution through 12 rounds of culturing experiments of the nanocellulose-producing bacterium Komagataeibacter hansenii ATCC 23769 in a liquid...
Adaptive laboratory evolution through 12 rounds of culturing experiments of the nanocellulose-producing bacterium Komagataeibacter hansenii ATCC 23769 in a liquid fraction from hydrothermal pretreatment of corn stover resulted in a strain that resists inhibition by phenolics. The original strain generated nanocellulose from glucose in standard Hestrin and Schramm (HS) medium, but not from the glucose in pretreatment liquid. K. hansenii cultured in pretreatment liquid treated with activated charcoal to remove inhibitors also converted glucose to bacterial nanocellulose and used xylose as carbon source for growth. The properties of this cellulose were the same as nanocellulose generated from media specifically formulated for bacterial cellulose formation. However, attempts to directly utilize glucose proved unsuccessful due to the toxic character of the lignin-derived phenolics, and in particular, vanillan and ferulic acid. Adaptive laboratory evolution at increasing concentrations of pretreatment liquid from corn stover in HS medium resulted in a strain of K. hansenii that generated bacterial nanocellulose directly from pretreatment liquids of corn stover. The development of this adapted strain positions pretreatment liquid as a valuable resource since K. hansenii is able to convert and thereby concentrate a dilute form of glucose into an insoluble, readily recovered and value-added product-bacterial nanocellulose.
Topics: Acetobacteraceae; Cellulose; Glucose; Industrial Microbiology; Lignin; Polysaccharides, Bacterial; Zea mays
PubMed: 31038201
DOI: 10.1002/bit.26997 -
International Journal of Systematic and... Aug 2020Gram-negative, aerobic, chemo-organotrophic and bacteriochlorophyll -containing bacterial strains, KEBCLARHB70R, KAMCLST3051 and KAMCLST3152, were isolated from the...
Gram-negative, aerobic, chemo-organotrophic and bacteriochlorophyll -containing bacterial strains, KEBCLARHB70R, KAMCLST3051 and KAMCLST3152, were isolated from the thalli of and lichens. Cells from the strains were coccoid and reproduced by binary division. They were motile at the early stages of growth and utilized sugars and alcohols. All strains were psychrophilic and acidophilic, capable of growth between pH 3.5 and 7.5 (optimum, pH 5.5), and at 4-30 °C (optimum, 10-15 °C). The major fatty acids were C ω7 and C; the lipids were phosphatidylcholines, phosphatidylethanolamines, phosphatidic acids, phosphatidylglycerol, glycolipids, diphosphatidylglycerol and polar lipids with an unknown structure. The quinone was Q-10. The DNA G+C content was 67.8 mol%. Comparative 16S rRNA gene analysis together with other data, supported that the strains, KEBCLARHB70R, KAMCLST3051 and KAMCLST3152 belonged to the same species. Whole genome analysis of the strain KEBCLARHB70R and average amino acid identity values confirmed its distinctive phylogenetic position within the family . Phenotypic, ecological and genomic characteristics distinguished strains KEBCLARHB70R, KAMCLST3051 and KAMCLST3152 from all genera in the family . Therefore, we propose a novel genus and a novel species, gen. nov., sp. nov., for these novel members. Strain KEBCLARHB70R (=KCTC 72321=VKM B-3305) has been designated as the type strain.
Topics: Acetobacteraceae; Bacterial Typing Techniques; Bacteriochlorophyll A; Base Composition; DNA, Bacterial; Fatty Acids; Glycolipids; Lichens; Phospholipids; Phylogeny; RNA, Ribosomal, 16S; Russia; Sequence Analysis, DNA; Ubiquinone
PubMed: 32658637
DOI: 10.1099/ijsem.0.004318