AUTHOR=Zhou Jie , Xue Rui , Liu Shixun , Xu Ning , Xin Fengxue , Zhang Wenming , Jiang Min , Dong Weiliang 

TITLE=High Di-rhamnolipid Production Using Pseudomonas aeruginosa KT1115, Separation of Mono/Di-rhamnolipids, and Evaluation of Their Properties

JOURNAL=Frontiers in Bioengineering and Biotechnology

VOLUME=7

YEAR=2019

URL=https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2019.00245

DOI=10.3389/fbioe.2019.00245

ISSN=2296-4185

ABSTRACT=<p>Rhamnolipids (RLs) are important bioproducts that are regarded as promising biosurfactant for applications in oil exploitation, cosmetics, and food industry. In this study, the newly isolated <italic>Pseudomonas aeruginosa</italic> KT1115 showed high production of di-RLs. The highest yield of RLs by <italic>P. aeruginosa</italic> KT1115, reaching 44.39 g/L after 8 days of fermentation in a 5 L bioreactor, was obtained from rapeseed oil-nitrate medium after process optimization. Furthermore, we established a new separation process that achieved up to 91.82% RLs recovery with a purity of 89% and further obtained mono/di-rhamnolipids. Finally, ESI-MS analysis showed that the RLs produced by strain KT1115 have a high proportion of di-RLs (mono-RLs: di-RLs = 11.47: 88.53), which have a lower critical micelle-forming concentration (8 mN/m) and better emulsification ability with kerosene (52.1% EI<sub>24</sub>) than mono-RLs (167 mN/m and 41.4% EI<sub>24</sub>, respectively). These results demonstrated that <italic>P. aeruginosa</italic> KT1115 is a potential industrial producer of di-RLs, which have improved applicability and offer significant commercial benefits.</p>