Bioprocess development for the production of xylooligosaccharide prebiotics from agro-industrial lignocellulosic waste

Effect of Bioactive Peptides on Gut Microbiota and Their Relations to Human Health

Bioactive peptides derived from both exogenous and endogenous origins have been studied extensively to use their beneficial effects in humans and animals. Bioactive peptides exhibit beneficial bodily functions and contribute to a healthy gastrointestinal system by influencing barrier functions, immune responses, and gut microbiota. Gut microbiota is a diverse microbial community that significantly influences the overall well-being and homeostasis of the body. Factors such as diet, age, lifestyle, medication, and environmental circumstances can affect the composition and diversity of the gut microbiota. The disturbances or imbalances in the gut microbiota have been associated with various health problems. The interplays between bioactive peptides and gut microbiota are not fully understood, but bioactive peptides hold promise as modulators of the gut microbiota to promote gut health. Almost all the bioactive research on human health, including the development of therapeutics and nutritional interventions, uses cell culture, even though their direct biofunctional activities can only occur when absorbed in the intestine and into the blood system. This review focuses on the current understanding of bioactive peptides in gut microbiota and their impact and mechanisms on gut and human health. The novelty of this review lies in its comprehensive analysis of the multifaceted interactions between bioactive peptides and gut microbiota, integrating knowledge from diverse disciplines between microbiology and nutrition. By elucidating the underlying mechanisms and identifying current research gaps, this review offers an outlook on the potential of bioactive peptides in promoting gut health and shaping future therapeutic and nutritional interventions.

Synergistic microwave and acidic deep eutectic solvent-based pretreatment of Theobroma cacao pod husk biomass for xylooligosaccharides production

The bioconversion of lignocellulosic biomass into novel bioproducts is crucial for sustainable biorefineries, providing an integrated solution for circular economy objectives. The current study investigated a novel microwave-assisted acidic deep eutectic solvent (DES) pretreatment of waste cocoa pod husk (CPH) biomass to extract xylooligosaccharides (XOS). The sequential DES (choline chloride/citric acid, molar ratio 1:1) and microwave (450W) pretreatment of CPH biomass was effective in 67.3% xylan removal with a 52% XOS yield from total xylan. Among different XOS of varying degrees of polymerization, a higher xylobiose content corresponding to 69.3% of the total XOS (68.22 mg/g CPH) from liquid fraction was observed. Enzymatic hydrolysis of residual xylan from pretreated CPH biomass with low commercial xylanase (10 IU/g) concentration yielded 24.2% XOS. The MW-ChCl/citric acid synergistic pretreatment approach holds great promise for developing a cost-effective and environmentally friendly method contributing to the sustainable production of XOS from agricultural waste streams.

Computation-Aided Phylogeny-Oriented Engineering of β-Xylosidase: Modification of "Blades" to Enhance Stability and Activity for the Bioconversion of Hemicellulose to Produce Xylose

Hemicellulose is a highly abundant, ubiquitous, and renewable natural polysaccharide, widely present in agricultural and forestry residues. The enzymatic hydrolysis of hemicellulose has generally been accomplished using β-xylosidases, but concomitantly increasing the stability and activity of these enzymes remains challenging. Here, we rationally engineered a β-xylosidase from Bacillus clausii to enhance its stability by computation-aided design combining ancestral sequence reconstruction and structural analysis. The resulting combinatorial mutant rXYLOM25I/S51L/S79E exhibited highly improved robustness, with a 6.9-fold increase of the half-life at 60 °C, while also exhibiting improved pH stability, catalytic efficiency, and hydrolytic activity. Structural analysis demonstrated that additional interactions among the propeller blades in the catalytic module resulted in a much more compact protein structure and induced the rearrangement of the opposing catalytic pocket to mediate the observed improvement of activity. Our work provides a robust biocatalyst for the hydrolysis of agricultural waste to produce various high-value-added chemicals and biofuels.

Optimization of Xylooligosaccharides Production by Native and Recombinant Xylanase Hydrolysis of Chicken Feed Substrates

Poultry production faces several challenges, with feed efficiency being the main factor that can be influenced through the use of different nutritional strategies. Xylooligosaccharides (XOS) are functional feed additives that are attracting growing commercial interest due to their excellent ability to modulate the composition of the gut microbiota. The aim of the study was to apply crude and purified fungal xylanases, from Trichoderma harzianum, as well as a recombinant glycoside hydrolase family 10 xylanase, derived from Geobacillus stearothermophilus T6, as additives to locally produced chicken feeds. A Box-Behnken Design (BBD) was used to optimize the reducing sugar yield. Response surface methodology (RSM) revealed that reducing sugars were higher (8.05 mg/mL, 2.81 mg/mL and 2.98 mg/mL) for the starter feed treated with each of the three enzymes compared to the treatment with grower feed (3.11 mg/mL, 2.41 mg/mL and 2.62 mg/mL). The hydrolysis products were analysed by thin-layer chromatography (TLC), and high-performance liquid chromatography (HPLC) analysis and showed that the enzymes hydrolysed the chicken feeds, producing a range of monosaccharides (arabinose, mannose, glucose, and galactose) and XOS, with xylobiose being the predominant XOS. These results show promising data for future applications as additives to poultry feeds.

Insights into the recent advances of agro-industrial waste valorization for sustainable biogas production

Recent years have seen a transition to a sustainable circular economy model that uses agro-industrial waste biomass waste to produce energy while reducing trash and greenhouse gas emissions. Biogas production from lignocellulosic biomass (LCB) is an alternative option in the hunt for clean and renewable fuels. Different approaches are employed to transform the LCB to biogas, including pretreatment, anaerobic digestion (AD), and biogas upgradation to biomethane. To maintain process stability and improve AD performance, machine learning (ML) tools are being applied in real-time monitoring, predicting, and optimizing the biogas production process. An environmental life cycle assessment approach for biogas production systems is essential to calculate greenhouse gas emissions. The current review presents a detailed overview of the utilization of agro-waste for sustainable biogas production. Different methods of waste biomass processing and valorization are discussed that contribute towards developing an efficient agro-waste to biogas-based circular economy.