一株增香微生物的分离鉴定及其发酵产香条件优化

Isolation and identification of an aroma-producing strain and optimization of its fermentation condition

从14种烟叶表面筛选出一株能够利用烟末发酵产香的菌株GXY35,通过生理生化实验和16S r DNA序列对其进行分析,并用GC/MS对发酵液的香气成分进行分析。结果表明:GXY35分离株属于克雷伯氏杆菌,发酵液中特征香味物质4-乙烯基愈创木酚的含量最高。在单因素试验的基础上通过正交试验,对菌株的发酵条件进行优化。结果表明,最适宜的产香发酵条件为:料液比1∶20,接种量12%,发酵温度37℃,发酵时间72 h,p H值7.0。在此条件下,特征香味物质4-乙烯基愈创木酚的含量最高可达0.725 mg·m L-1。

An aroma-producing strain GXY35 was isolated from 14 kinds of tobacco leaves,and the aroma components were analyzed by gas chromatography-mass spectrometry（ GC / MS）. The strain was identified as Klebsiella sp. from physiological and biochemical characteristics and 16 S r DNA. The content of 4-vinylgualacol in fermentation broth was the highest. On the basis of single factor test,the fermentation condition of strain was optimized by orthogonal experiment. The optimal fermentation condition was as follows： the solid-liquid ratio of 1∶ 20,the inoculums size of 12%,the fermentation temperature of 37 ℃,the fermentation time of 72 h,and the initial p H of 7. 0. Under the optimal fermentation condition,the content of the characteristic favoring substance of 4-vinylgualacol was 0. 725 mg·m L^-1 .