Effect of fermentation conditions on lipase production by Candida utilis

Abstract

A wild yeast strain isolated from spoiled soybean oil and identified as Candida utilis initially presented rather low lipase activity (approximately 4 IU dm-3) in submerged culture in a universal yeast medium containing 2 % malt extract. Stu­dies were undertaken to improve the lipase production. The best yields of lipase were obtained with a medium supplemented with caprylic and oleic acids as indu­cers, but higher concentrations of the former (> 0.5 %) had a negative effect on the lipase production and cell growth. The type of nitrogen source seemed also to be very important. The highest lipolytic activity of 284 IU dm-3 was achieved after 5 days of fermentation in a medium containing oleic acid and hydrolyzed casein as carbon and nitrogen sources, respectively, and supplemented with Tween 80®. It was shown that optimization of the fermentation conditions can lead to a significant improvement in the lipase production (more than 70-fold higher compared to the initial value obtained in the non-optimized medium).

Keywords

• Candida utilis
• lipase production
• media optimization
• hydrolyzed ca­sein
• oleic acid