交替假单胞菌BYS-2产褐藻胶裂解酶条件研究

Optimization of alginate lyase-producing conditions by Pseudoalteromonas sp. BYS-2

以褐藻酸钠作为褐藻胶裂解酶产生菌初筛培养基唯一碳源,从鲍鱼养殖水样中分离获得一株产褐藻胶裂解酶的微生物,形态学和分子生物学16S rDNA鉴定结果显示,该菌株为交替假单胞菌Pseudoalteromonas sp.BYS-2.对该菌株进行产酶条件研究,获得最适产酶配方为:褐藻酸钠1 g·L^(-1),葡萄糖0.5 g·L^(-1),酵母膏10g·L^(-1),黄豆饼粉3 g·L^(-1),(NH_4)_2HPO_4 3 g·L^(-1),初始培养基pH8.0;最佳产酶条件为:接种量2%(体积分数),装液量50 m L/250 m L,发酵温度20℃,摇床转速200 r·min^(-1),在此条件下发酵24 h酶活力可达5.29 U·m L^(-1),比优化前(1.57 U·m L^(-1))提高2.37倍.

With sodium alginate as the only carbon source of primary screening medium,one of the mi-croorganisms that producing alginate lyase had been isolated from abalone aquaculture water,which was identified as Pseudoalteromonas sp.BYS-2 via morphological characteristics and 16S rDNA sequence analysis. Based on the results of fermentation experiments,the optimal liquid medium consisted of those compounds as follow： sodium alginate 1 g ·^-1,glucose 0.5 g ·L^-1,yeast extract 10g ·L^-1,soybean cake powder 3 g · L^-1, （NH4）2HPO4 3 g · L 1,pH 8.0. The optimal fermentation conditions included： inoculation 2% （ volume fraction） ,medium volume 50 mL /250 mL, incubate temperature 20℃ and shaking speed 200 r·min^-1. Fermenting about 24 h under these conditions,alginate lyase activity could reach 5.29 U · mL^-1 which was 2.37 times higher than before optimization （1.57 U · mL^-1）.