Strain improvement and optimization for enhanced production of cellulase in Cellulomonas sp. TSU-03

An objective of this study was to develop high cellulase-producing bacteria by mutagenesis and optimization studies. Among 328 mutant strains of Cellulomonas sp. TSU-03, the mutant M23, NTG mutant, gave the highest value of cellulase activity 2008 U/mg protein) followed by mutant M17 (1884 U/mg protein) in CMC medium. The optimum medium and environmental conditions for cellulase production consisted of 4% wastepaper, 1% NaNO3 under cultivation temperature at 35°C with initial pH and agitation speed at 6 and 100 rpm, respectively. Cellulomonas sp. strain M23 produced the highest cellular growth (28.09 ± 2.28 g/L) and FPase, CMCase as well as, β-glucosidase activities at 325, 2420 and 152 U/mg protein, respectively. Under optimal condition, the cellulase activity achieved from strain M23 is 1.28- and 1.30-fold higher than cellulase from mutant M17 and wild type, respectively. After being subcultured 12 times, the cellulase production of the mutant M23 was stable. The results suggested that Cellulomonas sp. M23 had a good potential for production of cellulase by fermentation using a cultivation medium containing wastepaper as the main substrate. Key words: Mutagenesis, NTG, Ultraviolet, Wastepaper.