Isolation of Lipase-Producing Yeasts from Industrial Oily Residues in Different Culture Media

Abstract

The main goal of this work was to collect industrial oily residues and isolate lipolytic yeasts by selecting the best strain in relation to lipolytic and esterification activities and investigate the increase of production in shake flasks. A total of 78 yeasts were isolated on Yeast Malt agar and 44 strains with lipase-producing potential pre-selected on tributyrin agar. The yeast identified as Yarrowia lipolytica showed the highest lipolytic and esterification activities, reaching 2.67 U/mL and 464.65 U/g, respectively, at 48 h. Medium 4 showed major lipolytic (2.23 U/mL) and esterification (324.98 U/g) activity, concomitantly. The components of this medium were used in the factorial design; it was observed that an increase in the concentration of MgSO4 and olive oil decreased lipolytic activity significantly (p<0.05), and the other variables did not influence lipase production. The esterification activity and cell concentration were not affected significantly (p>0.05) for any of the variables studied. An increase in lipolytic activity was reached in trial 9 (5.12 U/mL) and trial 1 (5.23 U/mL) and the maximum esterification activity was 133.19 U/g (trial 14). Additionally, the trial 15 showed relevant activities (4.32 U/mL and 105.22 U/g) beyond the cell concentration (10.30 g/L), obtained concomitantly.