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Chitinase from Serratia marcescens GG5 was optimally active at pH 6.5 and temperature 50 oC. The enzyme retained 90% activity at 50 oC for 30 minutes. Addition of EDTA , Glutathione, Cysteine-HCl and Sodium azide (1mm) enhanced chitinase activity by 30, 10, 9 and 12% respectively. Chitinase from this bacterium degraded the swollen chitin into N-acetyl-D-glucosamine as revealed by Thin Layer Chromatography.
Chitin is a homopolymer of b (1-4)-linked N-acetyl-D-glucosamine (GlcNAc) residues. It is mainly derived from crustaceans such as shrimps and crab shells and has received attention as a useful biomass (Dahiya et al., 2005). Chitin is one of the major components of fungal cell wall (Tiara et al., 2002). The enzymatic degradation of chitin by many microorganisms takes place into two successive steps, namely with a chitinase (EC 3.2.1.14) of endotype and N-acetylglucosaminidase of exo-type (Matsuo et al., 1999).
Bacterial chitinases play a vital role in maintaining the ecological balance by degrading chitin into biologically useful form (Suzuki et al., 2002). Vibrio alginolyticus chitinase was used to hydrolyze colloidal chitin into chitopentose and chitotriose (Murao et al., 1992). Hydrolyzed product, N-acetyl-D-glucosamine has been reported to have anti-inflammatory response in ulcerative coilitis (Friedman and Skehan, 1980). However, for commercial applications, chitinases should be produced rapidly and in high titre using simple and inexpensive substrates. Chitin bioconversion has been proposed as a waste treatment alternative to the disposal of shellfish waste and some pretreated chitin was used as substrate for production of microbial chitinases (Dahiya et al., 2005). Serratia marcescens GG5 was isolated previously in our laboratory from stalks of buttonmushroom (Singh et al., 2005). The present study is an attempt to characterize the chitinase from Serratia marcescens GG5. Flake chitin, p-dimethylamino-benzaldehyde and bovine serum albumin were purchased from SD fine chemicals, Mumbai (India). All other chemicals and materials used in this study were of highest purity grade.
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