FACTORS INFLUENCING SYNTHESIS OF EXTRACELLULAR LIPASES BY YARROWIA LIPOLYTICA IN MEDIUM CONTAINING VEGETABLE OILS

Abstract

The aim of this study was to evaluate lipase activity of Yarrowia lipolytica KKP 379 in media containing selected vegetable oils as the sole carbon source. The highest activity for extracellular Yarrowia lipolytica lipases was obtained in a corn oil medium, which was almost two times higher compared to lipase activity in olive oil medium, while the lowest lipolytic activity was observed in medium containing rice and peanut oils. Literature suggested that free fatty acids, especially oleic acid present in olive oil, are good inducers of microbial lipase synthesis, however the results of this study do not support the hypothesis that high oleic acid content stimulates high lipolytic activity. Neither the relationship between the percentage of individual fatty acids in triacylglycerols of vegetable oils nor their content at the sn-1,3 positions influenced the activity of extracellular lipases synthesized by Yarrowia lipolytica KKP 379. Several hypothesis are given regarding the presence of other factors which may determine differences in extracellular lipolytic activity of yeast grown on different vegetable oils, such as presence of metal ions, the content of free fatty acids and critical micellar concentration.