Enhanced Fermentation for Rhamnolipid Production in a Membrane Bioreactor with a New Strain Pseudomonas aeruginosa BC1

A novel fermentation process was conducted to enhance rhamnolipid (RL) production with a new strain─Pseudomonas aeruginosa BC1 (P. aeruginosa BC1)─in a pervaporation membrane bioreactor. The strain P. aeruginosa BC1 which can produce glycolipid biosurfactants─rhamnolipids (RLs)─was isolated from oil-field wastewater by the screening and purification process. Furthermore, one fermentation and membrane separation technology─pervaporation─were coupled to enhance the RL production by in situ removing the volatile organic compounds, which possibly inhibit the cell growth, with the membrane technology. When glucose and glycerol were utilized as carbon sources separately, RL production from the fermentation-membrane separation coupling system was elevated by 38 (up to 1.6 g/L) and 134% (up to 3.6 g/L), respectively, compared with the fermentation without membrane separation. With the broth and extracted RLs, oil displacement experiments presented 76% heavy oil stripping from artificial quartz sand.