-
Sheng Wu Gong Cheng Xue Bao = Chinese... Jun 2024Bacterial cellulose (BC) is a biopolymer synthesized by bacteria, which possess excellent characteristics such as high water holding capacity, high crystallinity, and...
Bacterial cellulose (BC) is a biopolymer synthesized by bacteria, which possess excellent characteristics such as high water holding capacity, high crystallinity, and high purity. It is widely used in food, medical, cosmetics, and functional films. is a model strain used in BC synthesis research. In bacteria, motility-related genes are associated with BC synthesis, whereas in CGMCC 2955, the functions of motility-related genes and their effects on BC synthesis are not known. To address this gap, we used the λ Red recombinant system to individually knock out , , and respectively, and constructed the knockout strains . -Δ, . -Δ, and . -Δ. Additionally, both and were disrupted to construct the . -Δ mutant. The results demonstrated that knockout strain . -Δ exhibited the highest BC yield, reaching (5.05±0.26) g/L, which represented an increase of approximately 24% compared to wild-type strains. Furthermore, the BC synthesized by this strain exhibited the lowest porosity, 54.35%, and displayed superior mechanical properties with a Young's modulus of up to 5.21 GPa. As knocking out and genes in . CGMCC 2955 did not reduce BC yield; instead, it promoted BC synthesis. Consequently, this research further deepened our understanding of the relationship between motility and BC synthesis in acetic acid bacteria. The knockouts of and genes resulted in reduced BC porosity and improved mechanical properties, provides a reference for BC synthesis and membrane structure regulation modification.
Topics: Cellulose; Acetobacteraceae; Gene Knockout Techniques; Bacterial Proteins; Gluconacetobacter xylinus; Genes, Bacterial
PubMed: 38914496
DOI: 10.13345/j.cjb.230684 -
Ultrasonics Sonochemistry Jul 2024A novel technique was proposed for processing silkworm pupae by combining plasma- activated water (PAW) with ultrasound (US). The microbial diversity and quality...
A novel technique was proposed for processing silkworm pupae by combining plasma- activated water (PAW) with ultrasound (US). The microbial diversity and quality characteristics of the silkworm pupae were also evaluated. The results of the microbial diversity analysis indicated that PAW combined with US treatment significantly reduced the relative abundance of Streptococcaceae, Leuconostocaceae, and Acetobacteraceae from 32%, 18% and 16% to 27%, 11% and 11%, respectively. Microstructural analysis demonstrated that the collapse of the internal structure of chitin in silkworm pupae facilitated the release of nutrients and flavour compounds including fatty acids, water-soluble proteins (WSP), amino acids, phenolics, and volatile compounds. Furthermore, the increase in antioxidant capacity and the decrease in catalase activity and malondialdehyde content confirmed the mechanism of quality change. These findings provide new insights into the possible mechanism of PAW combined with US to improve the quality of edible insects.
Topics: Animals; Pupa; Water; Bombyx; Ultrasonic Waves; Chemical Phenomena; Antioxidants; Biodiversity
PubMed: 38820934
DOI: 10.1016/j.ultsonch.2024.106927 -
Archives of Microbiology May 2024In many European regions, both local metallic and non-metallic raw materials are poorly exploited due to their low quality and the lack of technologies to increase their...
In many European regions, both local metallic and non-metallic raw materials are poorly exploited due to their low quality and the lack of technologies to increase their economic value. In this context, the development of low cost and eco-friendly approaches, such as bioleaching of metal impurities, is crucial. The acidophilic strain Acidiphilium sp. SJH reduces Fe(III) to Fe(II) by coupling the oxidation of an organic substrate to the reduction of Fe(III) and can therefore be applied in the bioleaching of iron impurities from non-metallic raw materials. In this work, the physiology of Acidiphilium sp. SJH and the reduction of iron impurities from quartz sand and its derivatives have been studied during growth on media supplemented with various carbon sources and under different oxygenation conditions, highlighting that cell physiology and iron reduction are tightly coupled. Although the organism is known to be aerobic, maximum bioleaching performance was obtained by cultures cultivated until the exponential phase of growth under oxygen limitation. Among carbon sources, glucose has been shown to support faster biomass growth, while galactose allowed highest bioleaching. Moreover, Acidiphilium sp. SJH cells can synthesise and accumulate Poly-β-hydroxybutyrate (PHB) during the process, a polymer with relevant application in biotechnology. In summary, this work gives an insight into the physiology of Acidiphilium sp. SJH, able to use different carbon sources and to synthesise a technologically relevant polymer (PHB), while removing metals from sand without the need to introduce modifications in the process set up.
Topics: Iron; Acidiphilium; Oxidation-Reduction; Hydroxybutyrates; Polyesters; Polymers; Culture Media; Biomass; Polyhydroxybutyrates
PubMed: 38775940
DOI: 10.1007/s00203-024-04005-4 -
New Biotechnology Sep 2024Natural biopolymers become increasingly attractive as bio-based alternatives to petrol-based rheological modifiers, especially in personal care applications. However,...
Comprehensive rheological analysis of structurally related acetan-like heteroexopolysaccharides from two Kozakia baliensis strains in surfactants and galactomannan blends.
Natural biopolymers become increasingly attractive as bio-based alternatives to petrol-based rheological modifiers, especially in personal care applications. However, many polysaccharides exhibit undesired properties in cosmetic applications such as limited viscosifying characteristics, unpleasant sensory properties, or incompatibility with certain formulation compounds. Here, a comprehensive rheological analysis of non-decorated acetan-like heteroexopolysaccharides derived from two Kozakia baliensis strains was performed in selected surfactant formulations. The results were compared to native xanthan gum and a genetically engineered xanthan variant, Xan∆gumFGL, which lacks any acetyl- and pyruvyl moieties and whose rheological properties are unaffected by saline environments. All four polysaccharides displayed a highly similar rheological performance in the non-ionic surfactant lauryl glucoside, while the rheological properties differed in amphoteric and anionic surfactants cocamidopropyl betaine and sodium laureth sulfate due to minor changes in side chain composition. Polysaccharide precipitation was observed in the presence of the cationic surfactant. Nevertheless, the native heteroexopolysaccharide derived from K. baliensis LMG 27018 shows significant potential as a salt-independent rheological modifier compared to the genetically engineered Xan∆gumFGL variant. In addition, blends of heteroexopolysaccharides from K. baliensis and several galactomannans displayed synergistic effects which were comparable to native xanthan gum-galactomannan blends. This study shows that heteroexopolysaccharides of K. baliensis are capable of further extending the portfolio of bio-based rheological modifiers.
Topics: Mannans; Rheology; Galactose; Surface-Active Agents; Polysaccharides, Bacterial; Glycosaminoglycans
PubMed: 38750817
DOI: 10.1016/j.nbt.2024.05.003 -
Scientific Reports May 2024Bacterial cellulose (BC) is a natural polymer renowned for its unique physicochemical and mechanical attributes, including notable water-holding capacity, crystallinity,...
Bacterial cellulose (BC) is a natural polymer renowned for its unique physicochemical and mechanical attributes, including notable water-holding capacity, crystallinity, and a pristine fiber network structure. While BC has broad applications spanning agriculture, industry, and medicine, its industrial utilization is hindered by production costs and yield limitations. In this study, Rhizobium sp. was isolated from bean roots and systematically assessed for BC synthesis under optimal conditions, with a comparative analysis against BC produced by Komagataeibacter hansenii. The study revealed that Rhizobium sp. exhibited optimal BC synthesis when supplied with a 1.5% glucose carbon source and a 0.15% yeast extract nitrogen source. Under static conditions at 30 °C and pH 6.5, the most favorable conditions for growth and BC production (2.5 g/L) were identified. Modifications were introduced using nisin to enhance BC properties, and the resulting BC-nisin composites were comprehensively characterized through various techniques, including FE-SEM, FTIR, porosity, swelling, filtration, and antibacterial activity assessments. The results demonstrated that BC produced by Rhizobium sp. displayed properties comparable to K. hansenii-produced BC. Furthermore, the BC-nisin composites exhibited remarkable inhibitory activity against Escherichia coli and Pseudomonas aeruginosa. This study contributes valuable insights into BC's production, modification, and characterization utilizing Rhizobium sp., highlighting the exceptional properties that render it efficacious across diverse applications.
Topics: Cellulose; Plant Roots; Rhizobium; Acetobacteraceae; Anti-Bacterial Agents
PubMed: 38740945
DOI: 10.1038/s41598-024-61619-w -
Frontiers in Cellular and Infection... 2024High-fat diets (HFDs), a prevailing daily dietary style worldwide, induce chronic low-grade inflammation in the central nervous system and peripheral tissues, promoting...
High-fat diets (HFDs), a prevailing daily dietary style worldwide, induce chronic low-grade inflammation in the central nervous system and peripheral tissues, promoting a variety of diseases including pathologies associated with neuroinflammation. However, the mechanisms linking HFDs to inflammation are not entirely clear. Here, using a HFD model, we explored the mechanism of HFD-induced inflammation in remote tissues. We found that HFDs activated the IMD/NFκB immune pathway in the head through remodeling of the commensal gut bacteria. Removal of gut microbiota abolished such HFD-induced remote inflammatory response. Further experiments revealed that HFDs significantly increased the abundance of in the gut, and the re-association of this bacterium was sufficient to elicit inflammatory response in remote tissues. Mechanistically, produced a greater amount of peptidoglycan (PGN), a well-defined microbial molecular pattern that enters the circulation and remotely activates an inflammatory response. Our results thus show that HFDs trigger inflammation mediated by a bacterial molecular pattern that elicits host immune response.
Topics: Animals; Acetobacter; Diet, High-Fat; Disease Models, Animal; Drosophila melanogaster; Drosophila Proteins; Gastrointestinal Microbiome; Inflammation; NF-kappa B; Peptidoglycan; Signal Transduction
PubMed: 38716198
DOI: 10.3389/fcimb.2024.1347716 -
Cell Reports Apr 2024Microbial invasions underlie host-microbe interactions resulting in pathogenesis and probiotic colonization. In this study, we explore the effects of the microbiome on...
Microbial invasions underlie host-microbe interactions resulting in pathogenesis and probiotic colonization. In this study, we explore the effects of the microbiome on microbial invasion in Drosophila melanogaster. We demonstrate that gut microbes Lactiplantibacillus plantarum and Acetobacter tropicalis improve survival and lead to a reduction in microbial burden during infection. Using a microbial interaction assay, we report that L. plantarum inhibits the growth of invasive bacteria, while A. tropicalis reduces this inhibition. We further show that inhibition by L. plantarum is linked to its ability to acidify its environment via lactic acid production by lactate dehydrogenase, while A. tropicalis diminishes the inhibition by quenching acids. We propose that acid from the microbiome is a gatekeeper to microbial invasions, as only microbes capable of tolerating acidic environments can colonize the host. The methods and findings described herein will add to the growing breadth of tools to study microbe-microbe interactions in broad contexts.
Topics: Animals; Drosophila melanogaster; Microbiota; Acetobacter; Gastrointestinal Microbiome; Lactobacillus plantarum; Hydrogen-Ion Concentration; Lactic Acid
PubMed: 38583152
DOI: 10.1016/j.celrep.2024.114087 -
International Journal of Biological... May 2024The bacterial nanocellulose (BnC) membranes were produced extracellularly by a novel aerobic acetic acid bacterium Komagataeibacter melomenusus. The BnC was modified in...
The bacterial nanocellulose (BnC) membranes were produced extracellularly by a novel aerobic acetic acid bacterium Komagataeibacter melomenusus. The BnC was modified in situ by adding carboxymethyl cellulose (CMC) into the culture media, obtaining a BnC-CMC product with denser fibril arrangement, improved rehydration ratio and elasticity in comparison to BnC. The proteolytic enzyme bromelain (Br) and antimicrobial peptide nisin (N) were immobilized to BnC matrix by ex situ covalent binding and/or adsorption. The optimal Br immobilization conditions towards the maximized specific proteolytic activity were investigated by response surface methodology as factor variables. At optimal conditions, i.e., 8.8 mg/mL CMC and 10 mg/mL Br, hyperactivation of the enzyme was achieved, leading to the specific proteolytic activity of 2.3 U/mg and immobilization efficiency of 39.1 %. The antimicrobial activity was observed against Gram-positive bacteria (S. epidermidis, S. aureus and E. faecalis) for membranes with immobilized N and was superior when in situ modified BnC membranes were used. N immobilized on the BnC or BnC-CMC membranes was cytocompatible and did not cause changes in normal human dermal fibroblast cell morphology. BnC membranes perform as an efficient carrier for Br or N immobilization, holding promise in wound debridement and providing antimicrobial action against Gram-positive bacteria, respectively.
Topics: Nisin; Bromelains; Cellulose; Acetobacteraceae; Humans; Anti-Bacterial Agents; Wound Healing; Enzymes, Immobilized; Nanostructures; Microbial Sensitivity Tests
PubMed: 38574906
DOI: 10.1016/j.ijbiomac.2024.131329 -
New Biotechnology Jul 2024Novacetimonas hansenii SI1, previously known as Komagataeibacter hansenii, produces bacterial nanocellulose (BNC) with unique ability to stretch. The addition of vitamin...
Novacetimonas hansenii SI1, previously known as Komagataeibacter hansenii, produces bacterial nanocellulose (BNC) with unique ability to stretch. The addition of vitamin C in the culture medium increases the porosity of the membranes and their stretchability making them highly moldable. To better understand the genetic background of this strain, we obtained its complete genome sequence using a hybrid sequencing and assembly strategy. We described the functional regions in the genome which are important for the synthesis of BNC and acetan-like II polymer. We next investigated the effect of 1% vitamin C supplementation on the global gene expression profile using RNA sequencing. Our transcriptomic readouts imply that vitamin C functions mainly as a reducing agent. We found that the changes in cellular redox status are balanced by strong repression of the sulfur assimilation pathway. Moreover, in the reduced conditions, glucose oxidation is decreased and alternative pathways for energy generation, such as acetate accumulation, are activated. The presence of vitamin C negatively influences acetan-like II polymer biosynthesis, which may explain the lowered yield and changed mechanical properties of BNC. The results of this study enrich the functional characteristics of the genomes of the efficient producers of the N. hansenii species. Improved understanding of the adaptation to the presence of vitamin C at the molecular level has important guiding significance for influencing the biosynthesis of BNC and its morphology.
Topics: Cellulose; Transcriptome; Ascorbic Acid; Dietary Supplements; Acetobacteraceae
PubMed: 38531507
DOI: 10.1016/j.nbt.2024.03.004 -
Frontiers in Microbiology 2024Traditional Chinese medicine (TCM) is widely used in humans and animals, which is very important for health. TCM affects the body 's immunity and changes in intestinal...
BACKGROUND
Traditional Chinese medicine (TCM) is widely used in humans and animals, which is very important for health. TCM affects the body 's immunity and changes in intestinal flora. This study was conducted to investigate the effects of dietary Hong-bailanshen (HBLS) supplementation in horses on serum biochemical profile, antioxidant enzymes and gut microbiota.
METHODS
In this study, five horses were selected. On day 0, 14, 28, blood samples and feces were collected on days 0, 14, and 28 to analyse gut microbiota, serum biochemical and redox indexes.
RESULTS
The results showed that the addition of HBLS to horse diets significantly decreased the level of alanine aminotransferase, alkaline phosphatase, creatine kinase and malondialdehyde ( < 0.05, < 0.01) and significantly increased the activity of total antioxidant capacity, superoxide dismutase and catalase ( < 0.05, < 0.01). Compared with day 14, the levels of alanine aminotransferase, alkaline phosphatase and creatine kinase were significantly decreased; however, the level of catalase was significantly increased in the horses continuously fed with HBLS for 28 days ( < 0.05, < 0.01). Alpha diversity analysis was performed that chao1 ( < 0.05), observed_specicies, faith'pd and goods_coverage upregulated in the horses fed HBLS. A total of 24 differential genera were detected adding HBLS to diet increased the abundance of and , while reduced and ( < 0.05, < 0.01).
CONCLUSION
Adding HBLS to the diet could be a potentially effective strategy to improve horses' health.
PubMed: 38444806
DOI: 10.3389/fmicb.2024.1327210