Study On The Culture Conditions Of Marine Bacteria Vibrio Agarivorans-1 Producing Agarase

Agarase can catalyze agar the hydrolysis. Agarase is divided into α-agarase(E.C.3.2.1.158) and β-agarase( E.C.3.2.1.81) accordin g to the different fragmentation pattern.Agar oligosaccharides produced by enzymatic hydrolysis of agar have significant biolo gical activity,So agarase have a wide range of applications in the food,cosmetic industries and pharmaceutical. In addition, Agarase is also used as tool enzyme in physiolo gy,biology and cytology research. In this study, by single factor experiment and response surface analysis, producing agarase Vibrio agarivorans-1 strain fermentation conditions were optimized to get the best medium for nutrition group producing enzyme is: agar 0.312%; yeast extract 1.2%; peptone 0.05%, NaCl 3.514%; CaCl2 0.05%; NaCl 2.5%; FePO4 0.1%; K2HPO4 0.1%; FeSO4 0.03%.Optimum fermentation conditions is: fermentation temperature 40℃, the optimum medium pH 7.0; medium loadin g capacity in 250 mL Erlenmeyer flasks 40 mL, inoculum size 6%; on shaker at 160 r/min. The highest enzyme activity of broth reached 9.304 U/ mL when cultured for 48 h under these culture conditions. Preliminary studying enzymatic properties of agarase determine the optimum temperature of the enzyme is 40 ℃, in 30 min,Agarase is better stability in 20-50℃. The enzyme activity retained more than 80%.The optimum pH is 7.0. Enzyme activity is a better stability within the range of pH 6-8. When the agar substrate concentration reached 0.2%, enzyme activity is the highest. Mn2+、 Zn2+、Cu2+ and Al3+ inhibited enzyme activity strongly. the enzyme activity was less affected by Na+ and K+.