胁迫条件及脂肪酸对巴氏醋杆菌生理特性的影响

Effect of Different Carbon Sources and Fatty Acids on Tolence of Acetobacter pasteurianus

研究巴氏醋杆菌7015在面对不同胁迫条件时(不同体积分数的乙酸和乙醇),细胞膜生理特性和胞内能量(ATP)的响应情况。研究表明,该巴氏醋杆菌在含有5%的乙醇胁迫条件下,细胞荚膜多糖合成量减少40.48%,胞内H+-ATPase活性增加了1.99倍,而胞内ATP含量减少了33.12%,同时细胞膜透性、细胞膜流动性均增加。在面对乙酸胁迫时除了细胞膜透性减弱外,其他生理特性和胞内能量状况跟乙醇胁迫时相似。在逆性环境下,添加外源脂肪酸对荚膜多糖含量无明显影响,但是不饱和脂肪酸(油酸和亚油酸)会增强细胞膜流动性及透性,而饱和脂肪酸(棕榈酸和硬脂酸)却减弱细胞膜流动性及透性。同时,不饱和脂肪酸更能促进胞内ATP的生成。

In this study, effect of carbon sources and tMty acids on membrane characteristics, activity- of H＋-ATPase and the intracellular content of ATP were investigated by using Acetobaz.ter pasteuricalus 7015. The results showed that the capsular polysaccharide decreased 40.48% when ethanol content reached 5%. And the plasma membrane H＋-ATPase activity- was increased 1.99 times and the concentration of ATP was increased 33.12% compared with glucose as sole carbon source. The effect of acetic acid on the physiological characteristics of A. pasteurianus was more significant. And exogenous fatty acid had no significant correlation with the synthese of bacterial polysaccharide. Oleic acid, linoleic acid increased the fluidity- and pahnitic acid, stearic acid decreased the fluidity. They all made the permeability decreased; and compared with the control, pahnific acid and oleic acid improved H＋-ATPase activity significantly, yet stearic acid reduced its activity. Moreover, unsaturated tarry acids promoted the tbrmation of intracellular ATP more than saturated tarry acids.