STUDIES ON PRODUCTION OF BIODIESEL FROM YEAST

Abstract

Biodiesel is a renewable resource of energy. It is regarded to face high energy prices and potential depletion of fossil oils reservoirs. It contributes to the reduction of carbondioxide and sulfur emissions to the atmosphere and has potential of being an environmentally solution for global warming, the energy crisis and depleted fossil fuel supplies. It is a mixture of fatty acids (FAs) methyl esters derived from triacylglycerols (TAGs). The biomass of oleaginous yeast is an optimal and abundant source of TAGs which exhibit similar FAs composition to plant oils. The present work aimed to study lipid-producingyeasts and promising for biodiesel production. The study included isolation of yeasts capable to producelipid, screening for the most efficient isolates, estimation of biomass, lipid weight and lipid content of this isolate,analysis the fatty acid profiles and determination of the optimum nutritional and environmental conditions for lipid production.

Results could be summarized as follow:- 1. Seventy six isolates of yeast were isolated from different sources included 23 isolates from soil samples and 2 isolates from organic manure, as well 22 yeast isolates from rotten fruits, 1 isolate from sugarcane juice, and 28 isolates from pickles, based on the typical morphological character of yeast using light microscope. 2. The lipid accumulation capacity of the isolated yeast was revealed by Sudan Black B staining of the cells grown in nitrogen-limited medium. The preliminary screening of all 76 yeast isolates showed that 33 isolates of yeast had the ability to accumulate lipids. 3. The quantitative assessment of selected 33 yeast isolates after growing on N-limiting medium was determined by extraction and estimation of cell dry weight, lipid weight and lipid content. It was observed that there were wide variations in cell dry weight, lipid weight and lipid content, between the different examined isolates.