KINETICS OF CELLULASE PRODUCTION BY CHAETOMIUM-GLOBOSUM AT DIFFERENT LEVELS OF DISSOLVED-OXYGEN TENSION USING OIL PALM EMPTY FRUIT BUNCH FIBER AS SUBSTRATE

The effect of different levels of dissolved oxygen tension (d.o.t) at a fixed agitation speed on the production of three major components of extracellular (free) cellulase (FPase, endoglucanase and beta-glucosi dase) by Chaetomium globosum strain 414 was investigated. Oil palm emp ty fruit bunch (OPEFB) fibre (10 g/l) and peptone (6 g/l) were used as carbon and nitrogen sources for cellulase production, respectively. G rowth of C. globosum and cellulase complex production were modelled us ing models based on logistic and Luedeking-Piret equations. The calcul ated data fitted well to the experimental data, indicating that the mo dels were suitable for describing and verifying growth and cellulase c omplex production at different d.o.t levels. Cell growth and cellulase production were approximately two-fold higher in the stirred tank fer menter as compared with shake flask culture. At d.o.t of between 30-50 % saturation, cell growth and cellulase production were higher than th ose under oxygen-limited conditions (5% saturation) and at high d.o.t (80% saturation). However, the highest activities of FPase (2.5 U/ml), CMCase (59.5 U/ml) and beta-glucosidase (12.8 U/ml) were obtained at a d.o.t of 50% saturation and these gave the overall productivities of 20.8, 495 and 53.3 U/l.h, respectively.