Enzymatic and Microbial Valorization of Lignocellulosic Biomass for Food Applications

Abstract

Meeting the rising global food demand requires the development of innovative and sustainable production strategies using emerging technologies such as artificial intelligence, synthetic biology, microbial protein production, cellular agriculture, and precision fermentation offering promising alternatives. The long-term viability of any such strategy, however, depends on access to affordable and renewable feedstock. Lignocellulosic biomass (LCB), the most abundant renewable material on earth, represents a promising carbon source due to its high sugar content. It comprises three main components: cellulose, hemicellulose, and lignin; the relative proportions of each component depend on the source. While lignin is a heteropolymer consisting of various phenolic compounds, cellulose and hemicellulose are polysaccharides composed of sugar molecules, such as glucose, xylose, and arabinose. Due to its high sugar content, LCB is widely considered a promising renewable carbon source for microbial fermentation, with potential applications in biofuel, biomaterials, and food industries. However, polysaccharides in LCB are not readily hydrolysable to supply fermentable sugars essential for microbial growth, as they form a complex, interconnected network with lignin to provide toughness to the plant cell wall. In addition to physical, chemical, and thermochemical methods, enzymes and microorganisms are extensively used in LCB valorization processes, including biomass pre-treatment, hydrolysis, and fermentation. The sustainable production of novel foods and food ingredients from LCB, particularly from agrifood side streams, offers an attractive strategy to enhance both waste management and food security simultaneously. This review discusses recent advances in microbial and enzymatic valorization of agrifood-derived LCB for food-related applications. We specifically highlight the conversion of lignocellulosic agrifood waste into various food ingredients, including single-cell protein, microbial oil, dietary fiber, and organic acids relevant to the food industry. Furthermore, we discussed current challenges and prospects of LCB valorization for food applications via biological routes.