Unleashing the industrial potential of microbial plant cell wall polysaccharide-degrading enzymes: recent advances in protein engineering

Plant cell wall polysaccharide-degrading enzymes (PCWPEs) used in industry are predominantly of microbial origin. Key enzyme classes, including cellulases, lytic polysaccharide monooxygenases (LPMOs), β-xylanases, β-mannanases and pectinases, have attained technological maturity and are widely deployed across agro-waste biorefineries, food and feed processing, textile and pulp manufacturing. Low catalytic efficiency, insufficient thermostability, poor operational adaptability, restricted functionality, and product inhibition limit the industrial use of these enzymes. Structure- and sequence-guided design, supported by computational design tools, now allows more targeted improvement of PCWPE performance. Yet, the stringent and context-specific performance requirements imposed by diverse industrial applications continue to present substantial challenges. This review systematically summarizes current engineering strategies for PCWPEs in the past decade, aiming to provide a comprehensive understanding of the tailored strategies employed in different engineering directions and to offer insightful proposals for future research.