Enhanced activity of intracellular agarase from a novel marine strain Agarivorans gilvus WH0801

摘要

A marine bacterium strain Agarivorans gilvus WH0801 with the efficient agar degradation ability isolated from fresh seaweed samples of Weihai coast was found to be potential in producing agarase. We studied on the optimal medium composition and culture conditions of Agarivorans gilvus WH0801 by statistical methods in shake flasks. First, several more important factors influencing agarase activity were selected by Plackett-Burman design. They are agar concentration, yeast extract concentration and seed age. Then the optimum levels of these three variables were further determined using Box-Behnken design. The highest agarase activity is obtained in the medium consisting of 2.49 g L~(-1) agar and 0.88 g L~(-1) yeast extract when the seed age is 25.64 h. The levels of other factors are 1 g L~(-1) peptone, 0.01 g L~(-1) ironic citrate at initial pH 7.0 and 28 °C. The whole optimization strategy results in the activity of agarase reaches 1.158 U mL~(-1), which is about 6.2-fold increase compares with the control.