酵母提取物对葡萄糖发酵生产生物破乳菌Alcaligenes sp. S-XJ-1的影响

Influence of Yeast Extract on the Fermentation of Glucose by the Demulsifying Strain Alcaligenes sp.S-XJ-1

以从石油污染的土壤中筛选出1株生物破乳菌Alcaligenes sp.S-XJ-1为对象,考察了以葡萄糖为碳源时添加酵母提取物对生物破乳菌菌体性质、破乳性能以及菌体元素组成的影响.结果表明,酵母提取物的投加能够有效提高生物破乳菌产量,在酵母提取物浓度为5 g.L-1时,生物破乳菌产量达到3.0 g.L-1,此时葡萄糖利用率亦达到最大的58%.随着酵母提取物的投加浓度的增大,培养得到的菌体破乳性能提高,在投加浓度为10 g.L-1时,破乳率达到76%;而培养得到的菌体C/N有所降低,对其菌体表面蛋白进行提取测定发现菌体总蛋白含量升高,这与FTIR分析破乳菌菌体表面蛋白质类物质提高的结论一致.推测该生物破乳菌菌体蛋白含量的提高增强了菌体的破乳性能,菌体蛋白类物质是影响其破乳性能的关键组分之一.

The demulsifying strain Alcaligenes sp.S-XJ-1,isolated from oil contaminated soil,was cultivated with glucose as the carbon source.The influences of yeast extract on the growth,demulsifying ability and the element composition of the strain were investigated.The results showed that the yeast extract could increase the biomass and enhance the glucose utilization of Alcaligenes sp.S-XJ-1.When the concentration of the yeast extract was 5 g·L-1,the biomass was increased up to 3.0 g·L-1,and the glucose utilization achieved 58%.The demulsifying ability of the strain was improved with increasing yeast extract concentration.When the concentration of the yeast extract was 10 g·L-1,the demulsification ratio of the obtained cell was 76%.While the C/N ratio of the cells decreased with the increasing concentration of yeast extract.The proteins of cells were extracted and measured.The results showed that the proteins of the obtained cell increased with the increasing concentration of yeast extract,in accordance with the increased concentrations of proteins on the surface of the cells as measured by FTIR.It is estimated that the increase of the proteins leads to the improvement of the demulsifying ability of the demulsifying strain and theses proteins play essential roles in the demulsifying process.