Study of Glycerol and Sweet Water as a Carbon Source for Production of Rhamnolipids by Naturally Occurring Strains of Pseudomonas aeruginosa (ATCC 10145 and ATCC 9027)

The interest in biosurfactant has increased considerably due to their large potential for industrial applications. Rhamnolipid is a simplest class of biosurfactants with well defined structure. The main obstacle in commercialization of biosurfactant especially rhamnolipids is the higher cost of the production. Glycerol is readily available from commercial fat-splitting process in the form of sweet water (up to 20% w/v) at very low cost. Two natural strains of Pseudomonas aeruginosa (ATCC 10145 and ATCC 9027) were compared for rhamnolipid production. The neotype strain of Pseudomonas aeruginosa (ATCC 10145) was found to produce more amounts of rhamnolipids than Pseudomonas aeruginosa (ATCC 9027) on glucose and glycerol as carbon source. The microbial growth (0.94 g/L) and formation of rhamnolipids (2.75 g/L) was maximum at 5% (w/v) glycerol concentration by Pseudomonas aeruginosa (ATCC 10145). The fermentation was monitored for 8 days on shake flask and magnetically stirred batch culture. In magnetically stirred batch culture, microbial growth was 0.69 g/L and 2.73 g/L of rhamnolipid was formed. Sweet water was also used as a source of glycerol.