Improved production of biosurfactant by a Pseudomonas aeruginosa mutant using vegetable oil refinery wastes.

Biosurfactant production by Pseudomonas aeruginosa EBN-8 mutant was studied in shake flasks on separate wastes from canola, soybean and corn oil refineries. Of the substrates tested, canola oil refinery waste (COD=20 g l(-1)) supplemented with sodium nitrate (at COD/N=20) showed the best microbial growth (4.50 g l(-1)) and rhamnolipid production (8.50 g l(-1)), at 10 d of incubation with the specific growth rate of 0.316 h(-1) and specific product yield of 0.597 g g(-1) h. Its cell-free supernatant showed the critical micelle dilution (CMD) of 150 and surface tension (ST) of 28.5 mN m(-1).