Search

Hydrogen is a clean energy carrier that can be used as fuel for fuel cells. Dark fermentative biohydrogen production with other waste biomass needs to be explored as an alternative for sustainable biohydrogen production in future. In this study, lab-scale bioreactor were carried out to produce biohydrogen from co-substrates using bacterial consortium at 37 ℃. For the experimental setup, a 1-L-working-volume reactor was used for biohydrogen production by bacterial monocultures and consortium on co-substrates. A batch experiment was performed at 37 °C with an initial pH of 7.0 and a mixing ratio of 600:300 between dairy whey and sugarcane bagasse. Total solids (TS), volatile solids (VS), total chemical oxygen demand (TCOD), soluble chemical oxygen demand (SCOD), and hydrogen production rate (HPR) were determined from co-substrates during the dark fermentation process. Morphologic changes of biohydrogen producing bacteria binds on co-substrates after the fermentation process were determined using SEM imaging. The bacteria can degrade the substrate when they attach to it causing hole formation and cracked the surface area. The level of biohydrogen production by bacterial consortium was observed and the results revealed a hydrogen production rate of 35.9 mL H 2 /L/h. In fermentative H 2 production, it is quite similar to that of most H 2 -producing bacteria previously studied, especially that of the bacterial consortium, and this indicates that the attempt to find an outstanding bacterial strain for fermentative H 2 production might be very difficult if not impossible., Competing Interests: Conflict of interestAll authors of this paper reveal that they do not have any significant conflicts of interest., (© King Abdulaziz City for Science and Technology 2024.)

The present study focused on the mushroom Ganoderma, which has been used in Eastern countries for centuries as a food and medicinal source. Specifically, the fruiting bodies of Ganoderma applanatum from the Kerala Forest Research Institute in Thirussur, Kerala, India, were analyzed for their nutritional and medicinal properties. The methanolic extracts of G. applanatum were used to examine secondary metabolites and proximate profiles, revealing the presence of various phytochemicals such as terpenoids, phenolics, glycosides, alkaloids, flavonoids, and saponins. Further analysis revealed the presence of significant amounts of calcium, sodium, phosphorus, and manganese. The compounds were characterized using chromatographic analysis, FTIR, and GC-MS, which revealed potential therapeutic compounds with C-H and C-O bonds in the amide group, β-glycosides, and C-C/C-O vibrations of phenolic substances. Mushroom extract at a concentration of 100 µg mL -1 exhibited potent antimicrobial activity against various pathogens. This study suggests that G. applanatum has a rich biochemical composition and pharmacological potential, making it a promising candidate for drug development and traditional medicine, and contributes valuable insights into its diverse therapeutic applications.

Naturally occurring biopolymers like exopolysaccharides (EPS) secreted by lactic acid bacteria (LAB) has gained significant attention as they are cost effective, renewable and safe. In order to prevent the rapid increase in antibiotic resistant bacteria, the EPS of LAB offers novel approach of targeting the antibiotic resistant pathogens by limiting their effects on environment. Accordingly, in this study, the production, purification, characterization and biological properties of exopolysaccharides from Lactococcus hircilactis strain CH4 and Lactobacillus delbrueckii strain GRIPUMSK were performed. The optimization of lactic acid bacterial strains for exopolysaccharide production was done by response surface methodology and changing the carbon sources in the growth media. The carbohydrate and protein of exopolysaccharide 1 were 79.7 % and 8.7 % respectively and exopolysaccharide 2 were 75.2 % and 9.3 % respectively. When compared with the commercial emulsifier sodium dodecyl sulfate, both the exopolysaccharides have shown good emulsifying activity. Both the exopolysaccharides were linear homo-polysaccharide as determined by Fourier transform infrared spectroscopy and Nuclear magnetic resonance spectra. Scanning electron microscopy showed that the exopolysaccharides were porous and capable of holding water. The exopolysaccharides were partially crystalline as confirmed by X-ray diffraction spectra. Exopolysaccharides from L. hircilactis and L. delbrueckii exhibited significant antimicrobial activity against H. pylori, S. flexneri, S. pyogenes, E. faecalis and C. albicans. Both the exopolysaccharides revealed significant 2,2-diphenyl-1-picrylhydrazyl and hydrogen peroxide scavenging ability with the IC 50 value of 100 μg/ml and 80 μg/ml respectively. Exopolysaccharides from L. hircilactis and L. delbrueckii at 100 μg/ml showed significant anticancer activity on HT-29 cells with 58.4 % and 58.7 % respectively. These findings proved that exopolysaccharides from the two selected lactic acid bacterial strains could be explored as natural bioactive carbohydrate polymer for biomedical applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The staggering increase in pollution associated with a sharp tightening in global energy demand is a major concern for organic substances. Renewable biofuel production through simultaneous waste reduction is a sustainable approach to meet this energy demand. This study co-fermentation of dairy whey and SCB was performed using mixed and pure bacterial cultures of Salmonella bongori , Escherichia coli , and Shewanella oneidensis by dark fermentation process for hydrogen production. The maximum H 2 production was 202.7 ± 5.5 H 2 /mL/L, 237.3 ± 6.0 H 2 /mL/L, and 198 ± 9.9 H 2 /mL/L obtained in fermentation reactions containing dairy whey, solid and liquid hydrolysis of pretreated sugarcane bagasse as mono-substrates. The H 2 production was greater in co-substrate by 347.3 ± 18.5 H 2 /mL/L under optimized conditions (pH 7.0, temperature 37 °C, substrate concentration 30:50 g/L) than expected in mono-substrate conditions, which confirms that co-fermentation of different substrates enhances the H 2 potential. Fermentation medium during bio-H2 production under GC analysis has stated that using mixed cultures in dark fermentation favored acetic acid and butyric acid. Co-substrate degradation produces ethyl alcohol, benzoic acid, propionic acid, and butanol as metabolic by-products. The difference in the treated and untreated substrate and carbon enrichment in the substrates was evaluated by FT-IR analysis. The present study justifies that rather than the usage of mono-substrate for bio-H 2 production, the co-substrate provided highly stable H 2 production by mixed bacterial cultures. Fabricate the homemade single-chamber microbial fuel cell to generate electricity., Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03687-9., Competing Interests: Conflict of interestAll authors of this paper reveal that they do not have any significant conflicts of interest., (© King Abdulaziz City for Science and Technology 2023. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)

Multidrug resistant (MDR) pathogens have become a major global health challenge and have severely threatened the health of society. Current conditions have become worse as a result of the COVID-19 pandemic, and infection rates in the future will rise. It is necessary to design, respond effectively, and take action to address these challenges by investigating new avenues. In this regard, the fabrication of metal NPs utilized by various methods, including green synthesis using mushroom, is highly versatile, cost-effective, eco-compatible, and superior. In contrast, biofabrication of metal NPs can be employed as a powerful weapon against MDR pathogens and have immense biomedical applications. In addition, the advancement in nanotechnology has made possible to modify the nanomaterials and enhance their activities. Metal NPs with biomolecules composite prevent the microbial adhesion and kills the microbial pathogens through biofilm formation. Bacteriocin is an excellent antimicrobial peptide that works well as an augmentation substance to boost the antimicrobial effects. As a result, we concentrate on the creation of new, eco-compatible mycosynthesized metal NPs with bacteriocin nanocomposite via electrostatic, covalent, or non-covalent bindings. The synergistic benefits of metal NPs with bacteriocin to combat MDR pathogens and COVID-19, as well as other biomedical applications, are discussed in this review. Moreover, the importance of the adverse outcome pathway (AOP) in risk analysis of manufactured metal nanocomposite nanomaterial and their future possibilities were also discussed., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 Elsevier B.V. All rights reserved.)

The current study aimed to screen bacteriocin producing LAB from different dairy products and evaluation of their biological properties. Initially, 12 (4-chess, 4-curd, and 4-yohurt) LAB species were isolated and only 4 isolates alone were selected based on their clear yellow halo zone around the colonies in the selective medium. The selected 4 isolates were identified based on their morphological and biochemical characteristics. Among them, the strain CH3 have showed better antimicrobial effects on selected human pathogens. The isolated strain CH3 were further identified as Lactococcus lactis strain CH3 (MZ636710) by SEM imaging and 16 s rRNA molecular sequencing. Bacteriocin was extracted from L. lactis strain CH3 and partially purified using 60 % ammonium sulphate and then completely purified by G-50 column chromatography. The purified bacteriocin showed a specific activity of 5859.37 AU/mg in 24.7 % of recovery and 10.9-fold purification. The molecular weight of bacteriocin was 3.5 kDa as observed in SDS-PAGE. The bacteriocin showed sensitivity to proteolytic enzymes and resistance to high temperature, wide range of pH, organic solvents and detergents. FT-IR spectral studies of bacteriocin detected the existence of OH/NH-stretching, CH, and COC and CO bonds. NMR spectrum showed one doublet and 4 various singlet peaks at different ppm, indicating the occurrence of six amino acids in the structure of purified bacteriocin. The purified bacteriocin have shown stronger antimicrobial and anti-biofilm activity against selected human pathogens at 100 μg/mL. SEM showed the evidence of structural deformation and loss of membrane integrity of bacterial cells treated with bacteriocin. Bacteriocin exhibited greater DPPH radical scavenging potential with an EC 50 value of 12.5 μg/mL. Bacteriocin have not shown significant toxicity on normal human dermal fibroblast (NHDF) cells (83.2 % at 100 μg/ mL). Furthermore, in silico studies using molecular modeling and docking were performed to know the proteins involved in antimicrobial action. The results suggests that bacteriocin could be an alternative to combat AMR pathogens and more suitable for food and dairy industries to preserve food without contamination., (Copyright © 2022 Elsevier B.V. All rights reserved.)