BIOCONVERSION OF MEAT PROCESSING FATTY WASTE USING YEAST Y.LIPOLYTICA

Abstract

A technology for the utilization of fat waste from meat processing based on a combination of physical and chemical effects and biological oxidation is proposed. The main chemical and microbiological parameters of the fat-containing phase of effluents of meat processing enterprises were determined. It was established that in the process of holding waste in a sludge collector (1…13 days) as a result of the vital activity of autochthonous microorganisms, the fat content decreases from 87 % to 58 %. The dominant organism of the autochthonous microflora of the waste is the fungus Geotrichum.sp. It was established that Yarrowia lipolytica yeast, selected for the substrate, is the most promising fat biodestructor. A method of pretreatment of the fat-containing solid phase of fatty effluents has been developed, which increases the efficiency of their consumption by the Yarrowia lipolytica culture. The basis of the method is the ultrasonic dispersion of fat mass, as a result of which the bioavailability of the substrate increases and, as a result, the specific growth rate and yield of microbial biomass increases by 11 % and 30 %, respectively. The methods of seed preparation are proposed, which allow to increase the efficiency of the main process according to the indicators: biomass yield (by 10.1 %); specific growth rate (from 0.20 to 0.26 h–1); protein content (by 16.7 %). The methods include the selection (5…7 passages) of high-performance clones, which is carried out in the directions of increasing affinity to the substrate and stress resistance to the action of hydrogen peroxide (2.5 g/l). The obtained results showed that when using yeast Yarrowia lipolytica for the biodestruction of fatty effluents, it is advisable to use both top-up and continuous methods of cultivation, which do not lead to significant changes in the quality of the obtained biomass. Yeast leaching was not observed in the top-up mode at 24 % withdrawal of culture liquid per hour, and in the case of continuous mode - at a flow rate of 0.24 h–1, while the protein and lipid content was 42.7 % and 7.2 %, 41.4 % and 7.9 %, respectively.