Study On The Fermentation And Separation Process Of Rhamnolipid

Rhamnolipids find broad applications as natural surfactants, emulsifiers, andantibiotics because of their low toxicity, high biodegradability and environmentalsoundness.The best initial concentration of nitrogen source, phosphorus source, traceelements respectively was3.2g/L,13.76g/L,5.17mL, and the final fermentationyield reached8.854g/L based on the shaking flask fermentation.A pH stage-controlled process of fermentation of rhamnolipids by Pseudomonasaeruginosa O-2-2was established. A yield of24.06g/L in batch fermentation wasachieved in a5-L fermentor via the optimization of stirring speed. By controlling pH,rhamnolipid production was increased to28.8g/L, an improvement of19.7%, andmore substrate was converted to rhamnolipids rather than to biomass. Fermentationkinetics models for cell growth, product synthesis and substrate consumption based onthe pH stage-controlled fermentation indicated that rhamnolipid production could befurther improved by fed-batch fermentation. Rhamnolipid production reached70.56g/L, an improvement of193%, in the pH stage-controlled fed-batch fermentationwhen the stirring speeds was controlled at500rpm and the fermentation temperaturewas maintained at30℃.A stable200L fermentation and separation process was established. And the finalfermentation production well maintained at70g/L。The structure of the rhamnolipid was determined through the use of highperformance liquid chromatography/electrospray ionization time-of-flight massspectrometer. The content of the four main rhamnolipid homologues respectively was1.18%,29.95%,43%,53.04%...