Recent progress towards industrial rhamnolipids fermentation: Process optimization and foam control.

The global market for rhamnolipids production holds great promise, and is in need of an economically viable mass-production scheme. Accordingly, several strategies have been employed to improve the efficiency of rhamnolipid production in the past few decades. Currently, rhamnolipids can be produced by Pseudomonas aeruginosa at a high yield (over 70 g/L) when vegetable oil is used as the carbon source under optimized fed-batch cultivations. However, severe foaming during rhamnolipid fermentation inhibits scaling-up and production efficiency. Stop valve was found to effective break the extremely stable rhamnolipids foams during fermentation, and production efficiency of rhamnolipids was highly improved, while its scale-up mechanism needs further study. In addition, the combination of both chemical and mechanical approaches is likely to be more efficiently resolving the foam problem existed in rhamnolipids fermentation than either chemical or mechanical methods alone.