Depletion of fossil fuels and increasing the environmental concerns against pollution accelerate the research in renewable energy with much efforts directed for the production of biodiesel by the promising oil-rich biomass, like oleaginous fungi, growing on inexpensive agricultural and industrial wastes. Rhizopus stolonifer was found to be the most potent lipid producer among the tested fungi in the present study; its growth was optimized at pH=6, glucose as C-source, NaNO3 as N-source, with agitation rate of 120 rpm, incubation temperature of 28 ͦ C after 6 days growth; which gave an observable lipid content of 57.9% dry wt. on non-detoxified liquid hydrolysate (NDLH) medium with saturated aliphatic long chains as revealed by GC-MS analysis. R. stolonifer gave noticeable activity of released sugar consumption (92.2%) on flax straw as a row material higher than rice, wheat straws and orange peel, forming high lipid content (54.33%) on flax; that was transesterified into biodiesel with cetane number of 61.48, that was higher than cetane number of the standard non-processed liquid diesel (< 47). So R. stolonifer can be considered as a good lipid producer on the depolymerized flax straw as a cheap source for biodiesel production.
Key words: Rhizopus stolonifer, biodiesel, oleaginous fungi, flax, agricultural wastes.
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