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

Abstract

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.