Rhamnolipid production, characterization and fermentation scale-up by Pseudomonas aeruginosa with plant oils.

Objective: To be competitive with common chemical surfactants, the cost of rhamnolipid production must be minimized by selecting suitable substrates and optimizing the fermentation process.

Results: With different plant oils as substrates, Pseudomonas aeruginosa TIB-R02 can produce rhamnolipids with different structural characteristics that were confirmed by HPLC/MS analysis. Different rhamnolipids had different performances in interfacial tension. The production of rhamnolipid was greatly enhanced by fermentation optimization with palm oil as substrate. A fermentation-defoaming tandem system was developed to resolve the problems of foaming and medium overflow during scale-up. Finally, the titer of rhamnolipid reached 60 g/l and the yield reached 80% in a 300 l fermentation-defoaming tandem system.

Conclusions: The work reveals the potential for producing high-performance rhamnolipids from renewable resources on a large scale.