Physicochemical pretreatment on food waste for enhanced production and extraction of biodiesel from oleaginous yeast strains

Abstract

The growing demand for fuel energy made the researches focus more on alternative fuel source. For the last few decades bio-fuel had gained more attention in order to meet the fuel requirements. One such alternative way in producing biodiesel, was the implementation of oleaginous microbes in the field of single cell oil production. Oleaginous organisms are capable of producing microbial oil, which measures around 70% of its body weight. Microorganisms capable of utilising the available carbon source for its existence, attained more importance in the field of waste management. On conceiving it, this study aimed at food waste to be used as a feedstock in bio-fuel production using oleaginous yeast strains. Even though food crisis was at peak globally, the amount of food waste generated worldwide was also too high. In India upto 40% of food produced was wasted, which in addition to food crisis pile up the organic loading to the environment as solid waste. In the current study, food waste was considered as the nutrient substrate for the oleaginous yeast to accumulate lipid within the cell. The food waste cannot be directly used as a medium for culturing of oleaginous yeast, because food consists of complex molecules whereas microbes feed on simple sugar. So the food waste was treated to make it a hydrolysate, where the complex organics were broken down to simpler forms. The feasibility study was carried out using three oleaginous yeast strains Lipomycesstarkeyi, Metschnikowiapulcherrima, and Yarrowialipolytica in utilising food waste hydrolysate (FWH) for the accumulation of microbial oil. It was found that the yeast strains were capable of producing 39.5%, 32.2% and 34.2% lipid of its dry cell weight respectively newline