产腈水合酶菌株的驯化选育及其产酶条件的优化

以Rhodococcussp YL 1为出发菌株 ,通过逐渐增加培养基中丙烯腈的浓度重复继代培养 ,得到 1株酶活为 79 8U/mg的腈水合酶高活力菌株YL 2 ,酶活比出发菌株YL 1提高了 87%。对菌株YL 2的产酶条件进行了优化。结果表明 ,葡萄糖、诱导剂脲、Co2 + 及pH是影响腈水合酶高效表达的主要因素。在葡萄糖浓度为 2 0g/L ,诱导剂脲的添加量为 0 0 6g/L ,钴离子加入量为 0 3g/L ;培养温度为 30℃ ,培养基初始 pH为 7 0的条件下培养 4 0h后 ,酶活可达 134 5U/mg ,比优化前提高了 6 9%。

Domestication of a Nitrile Hydratase Producing Strain and Optimization on Its Nitrile Hydratase Producing Conditions

A bacterial strain having higher nitrle hydratase activity and acrylonitrile concentration tolerance,numbered Rhodococcus sp. YL-2,was developed by repeated subculturing of Rhodococcus sp. YL-1 in the broth containing acrylonitrile with slightly increased acrylonitrile concentration.The specific nitrile hydratase activity of YL-2 increased up to 79.8 units/mg of dry cells,1.8 times higher than that of YL-1.The nitrle hydratase producing conditions were studied and optimized.The results showed that the factors influencing nitrle hydratase activity mostly were glucose, urea,Co 2+ and pH. Initial pH of broth was 7.0. After culturing 40 hours at 30℃ in broth containing 20g/L glucose,0.06 g/L urea,0.6 g/L Co 2+ , the nitrle hydratase activity of YL-2 can reach 134.5 units/mg of dry cells, 1.68 times higher than that of before optimization.