通过正交试验对产琼胶酶海洋菌株NBRC102603发酵条件进行了优化,优化得到的发酵产酶条件为:蛋白胨浓度5.0 g/L、酵母膏浓度1.25 g/L、琼胶浓度4.0 g/L、装瓶量100 mL、接种量1%、转速150 r/min,28℃下发酵48 h后酶活力达到58.94 U/mL,比未优化前提高了2.08倍。经纯化得到琼胶酶A和琼胶酶B,琼胶酶A纯化倍数为17.29倍,酶比活力为870.51 U/mg;琼胶酶B纯化倍数为16.65倍,酶比活力为838.39 U/mg。纯化后琼胶酶经SDS-PAGE检测,显示为单一条带,其相对分子质量酶A约为83.6 ku、酶B约为36.8 ku。

The fermentation conditions of an agar-degrading bacterium NBRC102603 isolated from the coastal water were optimized by using orthogonal experiment.The optimum condition for agarase production consisted of peptone 5.0g/L,yeast extract 1.25 g/L,agar 4.0g/L,1 % inoculating quantity,rate of shaking flask with 100 mL liquid in a 500 mL flask was 150 r /min.After 48h fermentation at 28℃,the enzyme activity was 58.94U/mL,which was 2.08 times higher than before optimization.After a serious of purification processes,two types of purified agarases of NBRC102603 were obtained,identified as agarase A and agarase B.Agarase A was purified 17.29-fold,with a specific activity of 870.51U/mg;while B was purified 16.65-fold,with a specific activity of 838.39U/mg.The purified enzyme A and B appeared to be homogeneous under the inspection of SDS-PAGE,and they had molecular masses about 83.6 ku and 36.8 ku.