Cellulase production by Cellulomonas biazotea cultured in media containing different cellulosic substrates

Abstract

Production of filter paper cellulase (FPase), endo-β-glucanase and β-glucosidase by Cellulomonas biazotea was investigated during growth on different substrates. The organism utilized four different cellulosics, NaOH-pretreated ground plant material of four lignocellulosic (LC) substrates grown on saline lands, three agricultural wastes, carboxymethyl cellulose (CMC), cellobiose and xylan as carbon sources in Dubos salts liquid medium and produced the enzymes. The highest level of volumetric productivity (Qp) of FPase occurred in the cell-free supernatants of C. biazotea during growth on α-cellulose followed by Leptochloa fusca (kallar grass), while that of endo-β-glucanase occurred on kallar grass followed by α-cellulose. Maximum β-glucosidase was produced in culture media containing cellobiose and kallar grass as carbon sources. Thus the production of these enzymes is influenced by the carbon source used. β-Glucosidase was produced mainly periplasmic and was several fold greater in quantity than that reported in other strains of Cellulomonas, as well as other bacteria. Kallar grass culture medium, during growth of C. biazotea, supported maximum Qp levels of 37.5, 17.5 and 6.1 IU/l/h for CMCase, FPase and β-glucosidase, respectively, with cell mass productivity of 0.235 g/l/h and was selected as a preferred substrate for cellulase production.