Microbial Cellulase Production - Microorganisms, Technologies and Factors: A Review
Ifeanyi Boniface Ezea *
Department of Applied Microbiology and Brewing, Enugu State University of Science and Technology (ESUT), PMB 01660, Agbani, Enugu State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Cellulase consists of three enzymes: β-glucosidase, endo-1, 4-β-D-glucanase (endoglucanase) and exo-1, 4-β-D-glucanase (exoglucanase). These three enzymes are involved in the hydrolysis of cellulose by synergetic action for accomplished and effective hydrolysis of cellulose. Cellulose is converted to simple sugar or glucose, which can be fermented into cellulosic products such as bioethanol or biofuel. Because of the important of cellulase, there is the need to elaborate more on cellulase production. Therefore, the aim of this research was to review microbal cellulase production microrganisms, technologies and factors. Bacteria such as Cytophaga hutichinsonii, Acetivibrrio cellulotytieus, Bacillus spp, Pseudomonas fluorescens etc. and Fungi, including Trichoderma viride, Trichoderma longibrachiatum, Aspergillus niger, Saccharomyces cerevisiae, Aspergillus niger, Aspergillus oryzae, Aspergillus flavus and Aspergillus fumigatus have been used for cellulase production. Substrate for cellulase production include the wastes of the following; green gram husk, black gram husk, rice bran, wheat bran, Rice husks, Banana peels, wheat husks, Corn waste and saw dust etc.There are two main fermentation techniques in cellulase production; submerged and solid state fermentation. Duration of fermentation, pH, temperature, nitrogen and moisture are among the factors that affect cellulase production. Cellulases have been utilized in various commercial sectors including agriculture, brewing, laundry, pulp and paper, biofuel and textile industry. Cellulases have diversified applications in the food industry.
Keywords: Cellulase, cellulose, microorganisms, substrate, solid state culture, submerged culture