【作者】 谭晓晶；

【导师】 孟延发；

【作者基本信息】 四川大学 ， 生物化学与分子生物学， 2006， 硕士

【摘要】 胆固醇酯酶（COE，EC3.1.1.13）在食品、医药等方面的功能日益受到重视，为此本课题从以下四个方面研究胆固醇酯酶，从而为它的应用提供依据：胆固醇酯酶高产菌株的筛选、菌株鉴定；胆固醇酯酶高产菌株培养条件的优化；胆固醇酯酶的分离纯化及纯度鉴定；胆固醇酯酶的酶学特性研究。 经过筛选，从21株菌株中筛选出一株胆固醇酯酶的高产菌株作为胆固醇酯酶的生产菌种。经鉴定，该菌株为马红球菌，其菌体呈橙红、橙黄色，为多形态的革兰阳性杆菌，生化反应不活泼，不能发酵任何糖、醇类，触酶呈阳性反应。药敏试验结果表明：马红球菌对环丙沙星、万古霉素等敏感率达100％；对青霉素等呈耐药反应。 以马红球菌作为研究对象，对此菌株胆固醇酯酶形成条件进行研究表明：马红球菌产生的胆固醇酯酶为诱导酶，其胞外活性高于胞内活性。当油酸和卵磷脂作为诱导物且是培养基中唯一碳源时产酶量最高，蛋白胨和牛肉膏是产酶的适合氮源。马红球菌经过诱导及发酵培养条件的优化，确定其最适培养基组成为（％）：蛋白胨1.3，KCl0.5，牛肉膏0.1，Na₂HPO₄0.632，MgSO₄0.06，油酸0.4，卵磷脂0.25；最适培养条件为：pH7.4，250mL三角瓶中装量40mL，接种量6.0％，摇床旋转速度180r／min，温度30℃，培养时间24h。更多还原

【Abstract】 The significant functions of cholesterol esterase(COE, EC3.1.1.13) in food processing and medical assay were recognized gradually and showed more and more potential. In this paper, four topics were investigated: screening and identification the strain produces cholesterol esterase, optimization of cholesterol esterase-forming conditions from Rhodococcus sp., purification and identification of cholesterol esterase from Rhodococcus sp., characterization of cholesterol esterase.Strain one clone that could produce cholesterol esterase was screened from 21clones. After been identificated, could know it was Rhodococcus sp. Rhodococcus sp. is a clone of polymorphous gram positive bacteria, orange thalli, inertial biochemical reaction, cannot ferment any glucide or alcohols. The result of drug sensitive test shows that: Rhodococcus sp. is sensitively with penitricin、 vancomycin, and non-sensitive with penicillin.Cholesterol esterase-forming conditions of Rhodococcus sp. were investigated. The results were obtained as follow: cholesterol esterase from Rhodococcus sp. was inducible enzyme, and extra-cellular enzyme activity was higher than intra-cellular enzyme. Oleic acid and lecithin, the substrates of the cholesterol esterase, were the best carbon sources, and they are also the best inducer. Peptone and Beef-extract were the best nitrogen sources for enzyme formation. The optimization of cultivation conditions was selected through更多还原