RAPESES CAKE – A PROMISING SOURCE OF LIPOLYTIC ENZYMES

Abstract

The purpose of the study is to evaluate the possibility of using the native microbiota of rapeseed cake as a source of new producers of lipolytic enzymes. Objectives: fermentation of rapeseed cake in the pre-sence of native microbiota; isolation of microorganism isolates; determination of their lipolytic activity. Fermentation of rapeseed cake was carried out at a hydromodulus of 1:9. The resulting suspension was kept in a shaker-incubator, then diluted 100, 1000 and 10000 times in sterile distilled water. From the resulting suspensions, consortia of microorganisms of the native microbiota of rapeseed cake were isolated; 16 isolates of microorganisms were obtained based on the morphology of the colonies. Lipolytic (twinase) activity was determined by the rapid indication method on media of various compositions. During the experiment, a solid nutrient medium was prepared with the following composition, g/l: bacterial peptone – 10; NaCl – 5; CaCl2 – 0.1; agar – 20. The medium was sterilized in an autoclave. Separately, 20 % solutions of Tween-20, -40, -60 and -80 were prepared and sterilized, after which they were mixed with an agar nutr¬ient medium under aseptic conditions and poured into sterile Petri dishes. Crops were sown on media with Tween by injection. Petri dishes with medium without inoculum were taken as a control. It was found that 10 out of 16 isolates exhibit lipolytic activity. The largest diameter of the precipitation zone was observed for group 8 and amounted to (23.2 ± 0.6) mm when incubated in a medium with TW40. The smallest dia¬meter was obtained for group 5 on a medium with TW20 (3.8 ± 0.5) mm. Further work is aimed at identi¬fying microorganisms in order to optimize the process of their cultivation and expand the range of industrial applications.