UTILIZATION OF CANOLA OIL AND LACTOSE TO PRODUCE BIOSURFACTANT WITH CANDIDA-BOMBICOLA

The prerequisites for a commercial fermentation process of biosurfacta nts include the use of low- or negative-cost substrates and maximum co nversion yields. Under competitive market conditions, the price of can ola oil is expected to decrease in response to its increased supply. L actose, obtained from cheese whey, is a by-product of the dairy indust ry. In this work, canola oil with glucose or lactose as carbon sources was used as substrates to produce sophorose lipids (SLs) by means of the yeast Candida bombicola. Fermentations were conducted in either sh aker flasks or 1-t Bellco (Vineland, NJ) stirred reactors for 5-7 d al 450 rpm and 30 degrees C. The production of SLs reached 150-160 g/L i n a medium consisting of 10% glucose, 10.5% cano[a oil, 0.1% urea and 0.4% yeast extract. When lactose was substituted for glucose, 90-110 g /L SL was obtained. The apolar SL opyranosyl-beta-D-glucopyranosyl]oxy )-octadecanoic acid 1'-4''-lactone 6',6''-diacetate (SL-1) was the maj or one (73%) when canola oil was used instead of safflower oil (SL-1, 50%). Use of canola oil generally resulted in increased yields of SLs comparable to the yields obtained when safflower oil was used in the m edium. Other literature reports present yields of 70 g/L and 120 g/L S Ls, respectively, with these substrates.