Bioproduction Of Fungal Cellulases And Hemicellulases Through Solid State Fermentation

Fungi produce extensive set of enzymes to degrade lignocellulosic plant biomass. Fungal (hemi) cellulases are among the most widely exploited microbial enzymes for many industrial and environmental applications. However, in biofuel industries and few other sectors, the cost of the enzymes is a big hurdle in the development of successful technology. So far industrial production of (hemi) cellulases is mainly achieved by submerged fermentation technique. But solid state fermentation (SSF) is an alternative low-cost and less energy-intensive technology which can lead to reduction in the cost of these enzymes. The chapter initially describes structure and occurrence of plant cellulose and hemicellulose and their degradation by fungal enzymes. Extracellular multienzyme systems of wood-rotting fungi, plant-pathogenic fungi, and thermophilic fungi are also reviewed. Production of (hemi) cellulases by SSF is explained with discussion on critical factors affecting the process and their optimization. Additionally, attempts to develop large-scale SSF processes using bioreactors are also described. Improvements of fungal (hemi) cellulases by genetic approaches and the current applications of (hemi) cellulases along with bioconversions of lignocellulosic waste into valuable products for use as energy source or food additives are briefly narrated.