耐有机溶剂低温碱性脂肪酶产酶条件优化及其酶学性质

Optimization of Enzyme Production Conditions and Enzymatic Properties of Organic Solvent-Tolerant and Cold-Adapted Alkaline Lipase

[目的]研究沙雷氏菌JXJ-54胞外脂肪酶的产酶条件以及粗酶酶学性质。[方法]以沙雷氏菌JXJ-54为出发菌株,采用单因素分析优化其产胞外脂肪酶的条件并对该酶进行酶学性质研究。[结果]该菌株的最佳产酶条件为牛肉浸膏10 g/L、K_2HPO_4 2 g/L、菜籽油乳化液体积分数2.25%,初始pH 9.0、培养温度20℃、装样量40 mL、接种量2%、发酵时间20 h。JXJ-54脂肪酶的最适底物为对硝基苯酚辛酸酯和对硝基苯酚葵酸酯,在30℃、pH 8.5～9.5时酶活力最高,且具有一定的热稳定性和较好的pH稳定性;酶样品受到多数供试金属离子和EDTA的抑制,在供试表面活性剂和有机溶剂中具有良好耐受性,甚至处于激活状态。[结论]该菌株能利用简单的发酵培养基达到较好的产酶效果,其所产胞外脂肪酶为低温碱性脂肪酶,具有一定的热稳定性和较好的pH稳定性,在供试表面活性剂和有机溶剂中具有良好的耐受性,在食品加工、洗涤剂、低温环境修复等低温碱性环境的工业领域中有一定的应用潜力。

[Objective]To study the enzyme production conditions and crude enzyme properties of Serratia JXJ-54 extracellular lipase.[Method]In order to maximize extracellular lipase production from Serratia JXJ-54,enzyme production conditions were optimized by single factor analysis.[Result]A maximum extracellular lipase production was achieved after 20 h fermentation in 40 mL medium,consisting of beef extract 10 g/L,K 2HPO 4 2 g/L,and rapeseed oil emulsion 2.25%(V/V),at an initial pH 9.0 in 250 mL erlenmeyer flask with 2%inoculum at 20℃.The best substrates of the crude lipase were p-nitrophenyl caprylate and p-nitrophenyl decanoate.The crude lipase exhibited highest activity at 30℃and pH 8.5 to 9.5,it had some thermal stability and good pH stability.Enzyme samples were inhibited by most metal ions and EDTA,and were well tolerated or even activated in surfactants and organic solvents.[Conclusion]The strain JXJ-54 can use simple fermentation medium to obtain better lipase production,its cold-adapted alkaline lipase has some thermostability and better pH stability and shows high tolerance to the tested surfactants and organic solvents.Therefore,in the industrial field of low temperature and alkaline environment,such as food processing,detergent and low temperature environmental remediation,the JXJ-54 lipase has potential applications.