Debarking, pitch removal and retting: Role of microbes and their enzymes

Abstract

AbstractMicrobial enzymes are green and clean alternatives for several processes in the pulp and paper industry. Enzyme treatment decreases the energy requirement and minimizes the wood losses during drum debarking. Lipophilic wood extractives are known as pitch. Pitch deposition adversely affects the pulp quality and increases equipment maintenance and operating costs during paper manufacturing. Several chemical additives have been used to remove pitch deposits. Natural seasoning of wood is used to minimize pitch content in wood, but it has some disadvantages including yield losses and decreased brightness. Controlled seasoning with white-rot fungi or albino strains of sapstain fungi is an effective tool for degradation and removal of wood extractives. Enzymes including lipase, laccase, sterol esterase, and lipooxygenase have also been used to minimize pitch-related problems. Enzymatic retting has been proved an eco-friendly and economical solution for chemical degumming and traditional retting.