원문정보
초록
영어
This study was conducted to screen the alginate-degrading microorganism and purification and characterization of alginate-degrading enzyme. The alginate-degrading marine bacteria was isolated from brown algae Sargassum thunbergii. In the result of 16S ribosomal RNA sequence analysis, the strain was identified as Vibrio sp. V140 and named as Vibrio sp. PKA 1003. The optimum culture conditions for the growth of as Vibrio sp. PKA 1003 were pH 7, 3% NaCl, 25℃ and 24 hr incubation time. To obtained the crude enzyme, as Vibrio sp. PKA 1003 was incubated its optimum culture conditions and the culture medium of the bacterium was centrifuged for 30 min at 12,000 ×g, 4℃. The supernatant was utilized as crude enzyme and the optimal conditions for alginate-degrading ability of enzyme was measured by reducing sugar assay and viscometry. The crude enzyme of alginate-degrading bacteria, as Vibrio sp. PKA 1003, showed highest level of alginate-degrading activity when cultured on pH 9, 30℃, 6% alginic acid and 63 hr incubation time. The crude alginate-degrading enzyme produced by Vibrio sp. PKA 1003 was purified by ammonium sulfate salting, dialysis, DEAE-sephadex, sephadex G-100 and Sephacryl S-200 HR column. The effects of pH, NaCl and temperature on purified enzyme and the metal and substrate specificity was measured by reducing sugar assay.