Zhao Min, Zheng Yaqian, Yu Haiying, Ma Lüyan
State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Sheng Wu Gong Cheng Xue Bao. 2024 Mar 25;40(3):786-798. doi: 10.13345/j.cjb.230413.
Rhamnolipids (RLs) have emerged as one of the most promising classes of biosurfactants. The ratio of mono-RL to di-RL plays a significant role in determining its performance. Therefore, strains whose production of mono-RL and di-RL are manuplable, have advantage on applications in various scenarios. In this study, we developed a deletion mutant strain in PAO1, which produced primarily mono-RL. Subsequently, we generated two complemented strains by integrating the arabinose-induced P- gene, either directly into the chromosomes or expressing it on plasmids. Our results indicate that the ratio of mono-RL to di-RL synthesized by the complemented strain gradually decreased as the concentration of arabinose (the inducer) increased. Consequently, there was a decrease in emulsification ability and an increase in surface tension and critical micelle concentration (CMC) of the corresponding rhamnolipids. The complemented strains without inducer can produce a small amount of di-rhamnolipids, which enhanced the surfactant properties. Notably, the rhamnolipids induced by 0.10% arabinose exhibited the most potent antibacterial effect.
鼠李糖脂（RLs）已成为最有前景的生物表面活性剂类别之一。单鼠李糖脂与双鼠李糖脂的比例在决定其性能方面起着重要作用。因此，单鼠李糖脂和双鼠李糖脂产量可控的菌株在各种应用场景中具有优势。在本研究中，我们构建了一株PAO1缺失突变株，其主要产生单鼠李糖脂。随后，我们通过将阿拉伯糖诱导型P基因直接整合到染色体上或在质粒上表达，构建了两个互补菌株。我们的结果表明，随着阿拉伯糖（诱导剂）浓度的增加，互补菌株合成的单鼠李糖脂与双鼠李糖脂的比例逐渐降低。相应地，鼠李糖脂的乳化能力下降，表面张力和临界胶束浓度（CMC）增加。无诱导剂的互补菌株可产生少量双鼠李糖脂，这增强了表面活性剂性能。值得注意的是，0.10%阿拉伯糖诱导的鼠李糖脂表现出最强的抗菌效果。
