33A-24 |
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J.-H. KUK1, J.-S. Ahn1, W.-J. Jung1, Y.-L. Jin1, K.-H. Cho1, K.-H. Park2, and R.-D. Park1. (1) Glucosamine Saccharide Materials Laboratory (NRL), Division of Applied Bioscience and Biotechnology, Chonnam National University, 300 Yongbong-dong, Gwangju, 500-757, South Korea, (2) Division of Applied Bioscience and Biotechnology, College of Agriculture and Life Science, Chonnam National University, 300 Yongbong-dong, Gwangju, 500-757, South Korea N-Acetyl-b-D-glucosamine (GlcNAc) and chitin oligosaccharides were widely used in medicine, functional foods and agriculture. Although GlcNAc and chitin oligomers have been industrially produced by acid hydrolysis of chitin, this chemical process has problems including high input and high effluent production. This study was performed to develop biological methods for preparing chitin oligomers from chitin as an alternative to the chemical treatment. Bacteria having strong chitinolytic activity on agar medium containing swollen chitin as a sole carbon source were isolated from coastal soil, and named GJ-18, GJ-19, GJ-22 and GJ-23. The chitinase activities of crude enzymes from these strains were determined by Schales' method using 1% swollen chitin as a substrate at pH 5.0 and 37 C. The crude enzyme activities of the culture supernatants of GJ-18, GJ-19, GJ-22 and GJ-23 were 20.96, 28.14, 12.61 and 10.50 U/mg protein, respectively. Chitinase activity was maximal at the 5~6th day of culture. The enzyme preparations were more effective on the swollen form compared with the powdered chitin at 37 C, an optimal temperature. Quite selective production of GlcNAc and (GlcNAc)3 using the enzyme preparations was observed by TLC and HPLC analyses from swollen chitin, with a trace amount of (GlcNAc)2 and (GlcNAc)4. After incubation of reaction mixtures for 3 days at 37 C, yield of the reducing sugars were 70.6, 71.8, 20.2 and 23.9% by enzyme preparations of GJ-18, GJ-19, GJ-22 and GJ-23, respectively. These results suggest that the isolates are indeed avaluable enzyme source for production of chitin oligosaccharides from chitin by using enzymatic cleavage.
Session 33A, Carbohydrate: General
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