一株酯化酶细菌的分离、鉴定及代谢产物特征

Isolation and Characterization of Bacteria Producing Esterifying Enzyme

研究不同培养条件下酯化酶细菌的代谢产物特征。从浓香型大曲中分离得到一株产酯化酶细菌,用B iolog微生物自动分析系统进行鉴定,改变发酵时间、发酵初始pH值和培养温度等培养条件,用乙醇对发酵液进行萃取,并用气相色谱-质谱联用法(GC-MS)对其进行鉴定分析。结果表明:该菌株为嗜热葡糖苷酶芽孢杆菌(Geobacillus thermoglucosidasius)。随着培养时间的延长,甲醇及各种高级醇逐渐减少甚至消失,而酯类物质则逐渐增加;随发酵初始pH值的增加,酸类物质有所减少,在pH为7.5时,产生了较多的酯类物质,但乙酸、3-羟基-2-丁酮、乙醛和3-甲基-丁醇等代谢产物不会随发酵初始pH值变化而变化;随着培养温度的升高,酸类物质和醇类物质的种类有所增加,当培养温度为35℃时,产生更多的酯类物质。

The characterization of bacterial producing esterifying enzyme of different culture conditions were studied.A bacterial strain producing esterifying enzyme was isolated from Luzhou-flavor Daqu and it was identified by Biolog Microbes automated identification System.Culture conditions such as fermentation time,initial pH of fermentation and culture temperature were changed.The fermentatiom broth were extracted by ethanol and analyzed by GC-MS.The results show that the strain is Geobacillus thermoglucosidasius.When incubation time was prolonged,methanol and various higher alcohols were gradually decreased and even disappeared,but the ester were gradually increased.When the initial pH of fermentation was increased,the acid were decreased.When pH was 7.5,more ester were produced,but the metabolites were not changed with the initial pH of fermentation such as acetic acid,3-Hydroxy-2-butanone,acetaldehyde and 3-Methylbutyl alcohol etc.When the culture temperature increased,the kinds of the acid and alcohol slightly increased.When the culture temperature was 35℃,the more ester wre produced.