Assessment of process integration approach for coir biosoftening and lignin‐modifying enzyme production from agro residues

Abstract

AbstractLignin present in the inner core of natural lignocellulosic fibers is preferably removed for use in the textile industry as it hinders fiber spinnability. This study focuses on integrating the bioprocessing of agro residues and a natural fiber source (coir) for the effective production of lignin‐modifying enzymes while simultaneously softening the natural fibers. The lignin content in the raw fibers (42.17%) could be reduced by 14–31% by treating them with Phanerochaete chrysosporium for 30 days in the presence of agro waste, such as paddy straw, groundnut husk, corn husk, coir pith, sugarcane bagasse, saw dust and coconut leaf. Among the lignocellulosic wastes tested, P. chrysporium‐fermented groundnut husk with coir produced the maximum yield of lignin‐modifying enzymes (lignin peroxidase, 2.05 U mg−1; manganese peroxidase, 7.50 U mg−1; laccase, 0.43 U mL−1), while the tensile strength of the fiber was decreased by 9.9% compared with the raw fiber (110.14 MPa) on 30 days of incubation. Similarly, SB dust demonstrated good lignin‐modifying enzyme activity (lignin peroxidase, −1.57 U mg−1; manganese peroxidase, 8.14 U mg−1; and laccase, 0.35 U mg−1) as well as the tensile strength of the coir also being increased. A reduction in flexural rigidity owing to delignification was observed and hence a minimum 16% increase in softness was achieved in the integrated process. Our study presents an efficient strategy that exploits low‐cost agro residues for enzyme production and generates bio‐softened coir of acceptable quality in the export and domestic markets. © 2023 Society of Industrial Chemistry and John Wiley & Sons Ltd.