Abstract
Factors affecting the extracellular production of succinoyl trehalose lipids by Rhodococcus erythropolis SD-74 were studied to optimize the culture conditions for the maximum production. Since the optimal pH for the production of the acidic exolipid was about 7, the addition of phosphate buffer (pH 7) of high concentrations (0.3 to 0.4 M) to shake culture media was essential for exolipid production. A high osmotic equivalent of culture broth (about 2% NaCl equivalent value) was favorable for exolipid production. Although K+ was superior to Na+, chlorides at higher concentrations were more inhibitory for exolipid production compared to sulfates or phosphates. Under the optimal conditions in a jar tormentor, the concentration of the exolipid in the culture broth reached about 40 g/l after 10 days.
