Chitinase Activity of Serratia marcescens PT-6 Cultured in Bioreactor with Various Aeration Rate

Chitin is a biopolymer composed of N-acetylglucosamine (NAG) monomers. Bacterial chitinase helps in bioconversion process of chitin from shrimp shell waste into NAG. This study aimed to determine the effect of aeration on chitinase activity, NAG concentration in medium, bacterial growth, and pH medium; to determine the optimum aeration on chitinase production of Serratia marcescens PT-6. Chitinase was produced using a 1.5 L bioreactor at pH 7, 30°C, 200 rpm agitation speed, and variation of aeration rates (0.4, 0.6 and 0.8 vvm). Parameters examined included pH, bacterial growth (log CFU/ml), chitinase activity (U/ml), and NAG concentration in medium (µg/ml). Bacterial growth was measured by enumeration of bacterial colony in medium, while chitinase activity and NAG concentration were analyzed by colorimetric assay. Parameters was measured every 8 hours during 60 hours of incubation. Aeration rate showed a significant effect (P≤0.05) on chitinase activity and NAG concentration, but not significant (P≥0.05) on bacterial growth and pH medium. Optimum aeration rate on producing chitinase was 0.6 vvm with the highest chitinase activity of 0.0125 U/ml at 40 hours incubation. This study implies that optimization of bioreactor condition improved the production of chitinase by S. marcescens PT-6.