el-Shafei H A, Rezkallah L A
Microbial Chemistry Department, National Research Centre, Dokki, Cairo, Egypt.
Microbiol Res. 1997 Jul;152(2):199-208. doi: 10.1016/S0944-5013(97)80013-4.
The lipolytic activities in the supernatant fractions of Bacillus cereus and Bacillus coagulans cultures were investigated. Aeration, agitation, different media, emulsified oils, inoculum size and phase of growth affected lipase production. Aeration was essential for lipase production (air: medium ration 4:1) and produced the highest activity. The lipolytic activity reached a maximum level after incubation for two days with continuous agitation. It was also elevated by the presence of either olive oil or tributyrin and with lesser extent in the presence of castor oil. The enzyme levels were drastically reduced in the presence of animal fat, cotton seed oil, margarine or glycerol. The extracellular lipase enzyme from Bacillus cereus was purified with 46.2% overall recovery thought too steps, an acetone precipitation of the whole supernatant and purification by gel filtration on sephadex G-100. The efficiency of the purification process was evaluated through the polyacrylamide gel electrophoresis. The enzyme has an optimum pH 7.5 at the optimum incubation temperature of 40 degrees C. It is stable and retains its full activity after heating at 40-50 degrees C for 30 min. The activity is lost completely at 80 degrees C.
研究了蜡状芽孢杆菌和凝结芽孢杆菌培养物上清液部分的脂解活性。通气、搅拌、不同培养基、乳化油、接种量和生长阶段都会影响脂肪酶的产生。通气对脂肪酶的产生至关重要(空气:培养基比例为4:1),且产生的活性最高。在持续搅拌下培养两天后,脂解活性达到最高水平。橄榄油或三丁酸甘油酯的存在也会提高其活性,蓖麻油存在时活性提高程度较小。在动物脂肪、棉籽油、人造黄油或甘油存在时,酶水平会大幅降低。蜡状芽孢杆菌的细胞外脂肪酶通过两步法进行纯化,总体回收率为46.2%,即对整个上清液进行丙酮沉淀,然后通过葡聚糖G-100凝胶过滤进行纯化。通过聚丙烯酰胺凝胶电泳评估纯化过程的效率。该酶在最佳孵育温度40℃时的最佳pH值为7.5。它很稳定,在40 - 50℃加热30分钟后仍保留全部活性。在80℃时活性完全丧失。