Treatment of sugarcane bagasse for the immobilization of soybean β-glucosidase and application in soymilk isoflavones

Biodegradation of sugarcane bagasse biomass using recombinant alpha-galactosidase overexpressing whole-cell E.coli: a sustainable method of agricultural waste utilization

Whole-cell bacteria overexpressing a combo of enzymes capable of breaking down complex lignocellulosic components of cell wall is a path-breaking innovation that is eco-friendly for agricultural waste processing and sustainable environment. In this study, a whole-cell E. coli overexpressing the enzyme alpha-galactosidase is used to biodegrade sugarcane bagasse, presenting a sustainable approach for agricultural waste utilization. Alpha-galactosidase is an enzyme that breaks down alpha-D-galactose residues at the non-reducing ends of oligosaccharides (such as raffinose, stachyose, and verbascose), complex galactomannans, and galactolipids. Submerged and solid-state fermentation-mediated hydrolysis of bagasse waste using recombinant E. coli overexpressing α-galactosidase shows a decrease in the level of α-galactosides releasing sucrose and reducing sugars, indicating a continuous breakdown of the cell wall. Scanning electron microscopy indicates substantial disintegration of cell wall fibers under both submerged (12 h) and solid-state (7 days) fermentation, confirming the disruption of bagasse cell wall structural integrity. The 2XM9 media was found competent for both total protein and enzyme activity; the total protein concentration was 2553 µg/ml after 28 h of induction with an enzyme activity of 0.445 gal units/µg of protein after 16 h of induction at 24 °C. The results show that using whole-cell recombinant systems that express different cell wall-degrading enzymes could be a sustainable way to use agricultural waste, which would help with both waste management and protecting the environment.

Environmental impact of lignocellulosic wastes and their effective exploitation as smart carriers - A drive towards greener and eco-friendlier biocatalytic systems

In recent years, lignocellulosic wastes have gathered much attention due to increasing economic, social, environmental apprehensions, global climate change and depleted fossil fuel reserves. The unsuitable management of lignocellulosic materials and related organic wastes poses serious environmental burden and causes pollution. On the other hand, lignocellulosic wastes hold significant economic potential and can be employed as promising catalytic supports because of impressing traits such as surface area, porous structure, and occurrence of many chemical moieties (i.e., carboxyl, amino, thiol, hydroxyl, and phosphate groups). In the current literature, scarce information is available on this important and highly valuable aspect of lignocellulosic wastes as smart carriers for immobilization. Thus, to fulfill this literature gap, herein, an effort has been made to signify the value generation aspects of lignocellulosic wastes. Literature assessment spotlighted that all these waste materials display high potential for immobilizing enzyme because of their low cost, bio-renewable, and sustainable nature. Enzyme immobilization has gained recognition as a highly useful technology to improve enzyme properties such as catalytic stability, performance, and repeatability. The application of carrier-supported biocatalysts has been a theme of considerable research, for the past three decades, in the bio-catalysis field. Nonetheless, the type of support matrix plays a key role in the immobilization process due to its influential impact on the physicochemical characteristics of the as-synthesized biocatalytic system. In the past, an array of various organic, inorganic, and composite materials has been used as carriers to formulate efficient and stable biocatalysts. This review is envisioned to provide recent progress and development on the use of different agricultural wastes (such as coconut fiber, sugarcane bagasse, corn and rice wastes, and Brewers' spent grain) as support materials for enzyme immobilization. In summary, the effective utilization of lignocellulosic wastes to develop multi-functional biocatalysts is not only economical but also reduce environmental problems of unsuitable management of organic wastes and drive up the application of biocatalytic technology in the industry.