MUTAGENESIS OF CELLULOMONAS-BIAZOTEA FOR ENHANCED PRODUCTION OF XYLANASES

A rifampin-resistant mutant of Cellulomonas biazotea, designated 7 Rf( r), secreted elevated levels of xylanases in vivo. The xylanase and be ta-xylosidase production in the mutant was not inhibited in the presen ce of 5% glucose, cellobiose or glycerol in the solid medium. This mut ant showed approximately 2-3-fold enhanced product yield and productiv ity of cellular beta-xylosidase over the wild type parent in shake fla sk culture studies when grown on either cellobiose, cellulosic or lign ocellulosic (LC) substrates. Extracellular production of xylanase was also significantly (P less than or equal to 0.05) altered in the mutan t During growth of C. biazotea mutant derivative on xylan, maximum vol umetric productivities (Q(p)) for xylanase and beta-xylosidase were 49 3, and 30.7 IU/l/h, which were 1.21- and 2.29-fold improved over their respective values from the parental strain. The above values are stat istically (P less than or equal to 0.05) higher than the values report ed in some other xylanolytic mutant organisms. (C) 1997 Published by E lsevier Science Ltd.