正十六烷微生物降解酶的定域和酶促降解性

Study on Localization of Degradation Enzyme for n-Hexadecane and Enzymatic Degradability

以正十六烷为研究对象,通过室内实验,利用细胞静息技术提取了2株菌种的胞外酶、膜周酶及膜内酶对石油烃类污染物质的微生物降解酶定域,并研究了菌株受环境影响的产酶条件和酶的一般性质.结果发现：蜡状芽孢杆菌DQ01能降解正十六烷的关键酶位于膜周和膜内,芽孢杆菌DQ02降解正十六烷的关键酶是胞外酶和膜内酶.通过GC-MS对代谢产物进行测定发现,关键酶对十六烷的代谢途径是常见的单末端氧化.2株菌种产酶的最佳环境条件：ρ（正十六烷）为100 mg/L,c（鼠李糖脂）为2 mmol/L.另外,关键酶在pH为6.5-8.0的环境中活性较高,在pH为7.0左右时的活性最高.酶促降解性的最适温度为30℃.

Localization of degradation enzyme in two bacteria for n-Hexadecane, as well as production and characteristics of n-Hexadecanedegrading enzyme were studied. The cellular extracts of Bacillus cereus DQ01 were fractionated into extra-cellular, periplasmic and cytoplasmic fractions after osmotic shock. The results showed that the main enzymes, in the Bacillus cereus DQ01, which are cytoplasmic and membraneassociated enzymes, decomposed mainly n-Hexadecane. And most of the enzyme activities in Bacillus sp. DQ02 were detected in the cytoplasmic and extra-cellular extracts. The detection of metabolites revealed that the periplasmic and cytoplasmic enzymes can degrade n- Hexadecane by the most common pathway. Moreover, culture conditions have＇ a significant effect on the enzyme activity produced in hexadecane cultures of Bacillus cereus DQ01 and Bacillus sp. DQ02, and the optimal concentration of n-Hexadecane and rhamnnlipid is respectively 100 mg/L and 2 mmol/L. The enzyme is active when the pH is in the range of 6.5 ～ 8.0, and the most suitable pH is near 7.0. The enzyme is active at temperatures up to 30 ℃ .