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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 May 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.
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; Gastrointestinal Microbiome; Diet, High-Fat; NF-kappa B; Signal Transduction; Inflammation; Drosophila Proteins; Acetobacter; Drosophila; Peptidoglycan; Disease Models, Animal; Drosophila melanogaster
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 -
Microorganisms Dec 2023Fermented milk products (FMPs) contain probiotics that are live bacteria considered to be beneficial to human health due to the production of various bioactive...
Fermented milk products (FMPs) contain probiotics that are live bacteria considered to be beneficial to human health due to the production of various bioactive molecules. In this study, nine artisanal FMPs (kefir, ayran, khurunga, shubat, two cottage cheeses, bryndza, khuruud and suluguni-like cheese) from different regions of Russia were characterized using metagenomics. A metagenomic sequencing of ayran, khurunga, shubat, khuruud and suluguni-like cheese was performed for the first time. The taxonomic profiling of metagenomic reads revealed that species, such as and prevailed in khuruud, bryndza, one sample of cottage cheese and khurunga. The latter one together with suluguni-like cheese microbiome was dominated by bacteria, affiliated to (32-35%). In addition, a high proportion of sequences belonging to the genera and but not classified at the species level were found in the suluguni-like cheese. , as well as constituted the majority in another cottage cheese, kefir and ayran metagenomes. The microbiome of shubat, produced from camel's milk, was significantly distinctive, and , and represented the dominant components (42, 7.4 and 5.6%, respectively). In total, 78 metagenome-assembled genomes with a completeness ≥ 50.2% and a contamination ≤ 8.5% were recovered: 61 genomes were assigned to the , and families (the order within ), 4 to (the phylum) and 2 to (the phylum). A metagenomic analysis revealed numerous genes, from 161 to 1301 in different products, encoding glycoside hydrolases and glycosyltransferases predicted to participate in lactose, alpha-glucans and peptidoglycan hydrolysis as well as exopolysaccharides synthesis. A large number of secondary metabolite biosynthetic gene clusters, such as lanthipeptides, unclassified bacteriocins, nonribosomal peptides and polyketide synthases were also detected. Finally, the genes involved in the synthesis of bioactive compounds like β-lactones, terpenes and furans, nontypical for fermented milk products, were also found. The metagenomes of kefir, ayran and shubat was shown to contain either no or a very low count of antibiotic resistance genes. Altogether, our results show that traditional indigenous fermented products are a promising source of novel probiotic bacteria with beneficial properties for medical and food industries.
PubMed: 38276185
DOI: 10.3390/microorganisms12010016 -
International Journal of Biological... Mar 2024Bacterial cellulose (BC), a nanostructured material, is renowned for its excellent properties. However, its production by bacteria is costly due to low medium...
Bacterial cellulose (BC), a nanostructured material, is renowned for its excellent properties. However, its production by bacteria is costly due to low medium utilization and conversion rates. To enhance the yield of BC, this study aimed to increase BC yield through genetic modification, specifically by overexpressing bcsC and bcsD in Gluconacetobacter xylinus, and by developing a modified culture method to reduce medium viscosity by adding water during fermentation. As a result, BC yields of 5.4, 6.2, and 6.8 g/L were achieved from strains overexpressing genes bcsC, bcsD, and bcsCD, significantly surpassing the yield of 2.2 g/L from wild-type (WT) strains. In the modified culture, the BC yields of all four strains increased by >1 g/L with the addition of 20 mL of water during fermentation. Upon comparing the properties of BC, minimal differences were observed between the WT and pbcsC strains, as well as between the static and modified cultures. In contrast, BC produced by strains overexpressing bcsD had a denser microstructural network and exhibited demonstrated higher tensile strength and elongation-to-break. Compared to WT, BC from bcsD overexpressed strains also displayed enhanced crystallinity, higher degree of polymerization and improved thermal stability.
Topics: Gluconacetobacter xylinus; Cellulose; Fermentation; Nanostructures; Water
PubMed: 38242407
DOI: 10.1016/j.ijbiomac.2024.129552