Purification of chitosanase fromStenotrophomonas maltophiliaKPU 2123 andMicromonosporasp. T5a1 for chitooligosacharide production

Stenotrophomonas maltophilia KPU 2123 and Micromonospora sp. T5a1 are bacterial strains isolated from shrimp waste capable of hydrolyzing chitosan to produce chitooligosaccharides (COSs). Their COS products showed antimicrobial activity. The aim of this study was to purify chitosanase from those bacteria and used for COSs production. Chitosanase from both strains were produced using 0.5% colloidal chitin as inducer. The chitosanase was then purified by ultrafiltration, DEAE Sepharose ion exchange and Separacyl S-300 gel filtration chromatography. The specific activity and the yield of chitosanase KPU 2123 increased 2.35-fold and 30.90% after three steps of purifications, respectively, whereas chitosanase T5a1 increased 3.32-fold and 22.79%, respectively. The molecular weight of both chitosanases KPU 2123 and T5a1 were about 76 and 20 kDa, respectively. The COS products generated by chitosanase KPU 2123 contained N-acetyl-D-glucosamine, Di-N-acetyl-D-glucosamine, Tri-N-acetyl-D-glucosamine, Tetra-acetyl-D-glucosamine and Penta-N-acetyl-D-glucosamine while by chitosanase T5a1 contained N-acetyl-D-glucosamine, Di-N-acetyl-D-glucosamine. Based on their COS products, chitosanase KPU2123 can be categorized as endo-type chitosanase. Further study is needed to analysis the bioactivity of COSs obtained from the pure of chitosanases KPU 2123 and T5a1.