Microbial Cellulases and Their Characterization for Industrial Applications

Agricultural wastes being a type of lignocellulosic biomass are rich in carbon content, abundantly available and can form a sustainable feedstock for valorization. Microorganisms from lignocellulolytic environments have long been used to utilize lignocellulosic material for the large scale production of cellulolytic enzymes, which take part in the systematic degradation of lignocellulosic material. This paper reviews the various methodologies used for mining of microbial genes encoding cellulases. These include DNA library preparation, gene walking PCR, metagenomics and expression in hosts other than the conventional E. coli. Apart from this, the purification and characterization strategies involved to explore the tolerance of cellulases from different bacteria and fungi to a range of pH, temperature, metal ions and inhibitors have also been mentioned. In the end there is a discussion on the range of industrial applications where cellulases have been widely applied.