Optimization of Conditions for the Production of Alginate-degrading Crude Enzyme from Vibrio crassostreae PKA 1002

This study was conducted to screen an alginate-degrading microorganism and to investigate the characteristics of the alginate-degrading activity of its crude enzyme. A marine bacterium which produces extracellular alginate-degrading enzymes was isolated from the brown alga Sargassum thunbergii. 16S rRNA sequence analysis and physiological profiling resulted in the bacterium's identification as a Vibrio crassostreae strain, named Vibrio crassostreae PKA 1002. Its optimal culture conditions for growth were pH 9, 2% NaCl, 30℃ and a 24 hr incubation time. The optimal conditions for the alginate degrading ability of the crude enzyme produced by V. crassostreae PKA 1002 were pH 9, 30℃, a 48 hr incubation time and 8% alginic acid. The alginate degrading crude enzyme produced 3.035 g of reducing sugar per liter in 4% (w/v) alginate over 1 hr.