【摘要】 从油污土样中分离到一株高产胞外碱性脂肪酶的细菌，经鉴定为液化沙雷氏菌（Ｓｅｒｒａ－ｔｉａｌｉｑｕｅｆａｃｉｅｎｓ）。发酵上清液经超滤浓缩，ＤＥＡＥ纤维素层析，透析去盐后冻干得粗酶制品。初步研究发现粗酶的最适反应ｐＨ为８．０，最适反应温度４４℃；４５℃以下和ｐＨ７～９范围内十分稳定；金属离子对酶反应影响较大，Ｃａ２＋、Ｍｎ２＋、Ｂａ２＋可增强酶活性，而Ｆｅ３＋、Ｆｅ２＋则抑制酶活，Ｚｎ２＋和金属离子螯合剂ＥＤＴＡ可使酶失活；表面活性剂吐温２０对酶反应也有一定激活作用。液化沙雷氏菌脂肪酶的研究，目前国内外均未见报道更多还原

【Abstract】 Among 136 strains of bacteria secreting extracellular lipase,which were isolated from 150 oil contacted samples,one marked as S33 shows the highest lipolytic activity detected with olive oil as substrate.This strain was identified as Serratia liquefaciens ,whose lipase production had never been reported so far.Through ultratiltration,DEAE cellulose chromatography,dialysis and lyophilization,crude enzyme was obtained from the culture supernatant.The results of a series of experiments showed that the lipolytic activity of the crude enzyme was optimal at pH 8.0 and 44℃.The enzyme keeps stable within the range of pH 7.0～9.0 and at a temperature below 45℃.Its activity is increased with amendment of Ca 2+ ,Mn 2+ , Ba 2+ ,and partly inhibited by Fe 3+ ,Fe 2+ ,and completely inhibited by Zn 2+ and the metal chelating agent EDTA更多还原