Expression Pattern of β-glucanase and Production of Water-soluble Polysaccharide in Pedobacter sp. PR-M6

The expression pattern of β-glucanase isozymes produced by Pedobacter sp. PR-M6 cultured in the presence of 0.1% laminarin was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The β-glucanase isozymes appeared as seven bands ( β G1, La1, La2, β G4, β G5, β G6 and, β G7) on the gel. Four of the isozymes ( β G1, β G4, β G5, and, β G7) were normally expressed in samples cultured at 20°C and 30°C. Three of the isozymes ( β G6, La1, and La2) were expressed exclusively in samples cultured at 30°C. Cell growth of Pedobacter sp. PR-M6 was higher when cultured at 30°C than at 20°C. The activity of β-glucanase increased up to 40°C, followed by a decrease in activity by 50°C. Thin layer chromatographic (TLC) analysis revealed the presence of monomeric and dimeric reducing sugars in products obtained from the culture media when the cultures were incubated at 4°C, 20°C, 30°C, and 40°C. From hydrolysis of WSP, rhamnose, mannose, and glucose were major monosaccharide by TLC and HPLC works. The average molecular weight of WSPs isolated from the supernatant of the PR-M6 culture medium containing laminarin as substrate was approximately 9.1 kDa. These results indicate that WSPs produced by Pedobacter sp. PR-M6 have potential as a new resource for biotechnological applications.