鼠李糖脂在铜绿假单胞菌NY3代谢烃过程中的生理作用

Rhamnolipid on physiological property of strain Pseudomonas aeruginosa NY3 in metabolic process of hydrocarbon

为了解鼠李糖脂在菌代谢烃过程中所起的具体作用,对NY3菌体生理生化指标进行测定,研究了NY3菌降解烃过程中,鼠李糖脂促进烃降解与细胞生理特性变化规律的相关性。结果表明,投加60、100和140 mg/L鼠李糖脂,能使正十六烷降解率分别提高23.7%、48.3%和32.2%,且产酸明显。鼠李糖脂能加快疏水性有机物的传质速度,与未加鼠李糖脂相比,鼠李糖脂浓度为100和140 mg/L时,菌细胞内积聚的正十六烷量增加12.5%和37.69%。鼠李糖脂存在下,NY3菌细胞内正十六烷吸收是一个积累和消耗相互交替的动态过程。鼠李糖脂使菌体细胞中疏水性脂类的相对含量和细胞表面的负电荷明显增加,但使所生长的细胞内脂多糖含量明显减少,生长过程投加鼠李糖脂浓度为60、100、140和200mg/L时,细胞中脂多糖含量分别减少45.65%、58.13%、45.61%、和59.44%。因此,鼠李糖脂能加快NY3菌对十六烷的降解,同时对代谢过程中菌体的生理生化特性有明显的改变。

To understand the specific function of rhamnolipid complexes in the process of hydrocarbon degradation,hexadecane degradation and changes in cell physiological properties were studied by assessing the physiological and biochemical indexes of Pseudomonas aeruginosa NY3. The degradation of hexadecane increased by23. 7%,48. 3%,and 32. 2% for rhamnolipid concentrations of 60,100,and 140 mg / L,respectively. In addition,acid production improved significantly; compared with the blank controls,the amounts of hexadecane that accumulated in cells increased by 12. 5% and 37. 69% for 100 mg / L and 140 mg / L of rhamnolipids,respectively. Additionally,rhamnolipids accelerated the transfer rate of hydrophobic organic contaminants. In the presence of rhamnolipids,the absorption of N-hexadecane in NY3 bacteria was a dynamic process that alternated between accumulation and consumption. The relative amount of hydrophobic esters contained in cells and the zeta potential of cell surfaces clearly increased by the addition of rhamnolipids; however,the amount of lipopolysaccharides decreased. When the concentrations of rhamnolipids were 60,100,140,and 200 mg / L,the amount of lipopolysaccharides contained in cells decreased by 45. 65%,58. 13%,45. 61%,and 59. 44%,respectively. Therefore,it can be inferred that rhamnolipids accelerate the degradation of hexadecane and alter the physiological and biochemical characteristics of P. aeruginosa NY3 during the metabolic process.