Use of a carbohydrate source and oil waste in lipid production by Mucor hiemalis

Microbial lipid production has attracted the attention of researchers for several reasons − inexpensive substrates, a valuable fatty acids content, and rapid growth of microorganisms. In this study, the efficiency of total lipid and fatty acids production by Mucor hiemalis PTCC 5292 using a carbohydrate source and oil wastes was compared. Spores of Mucor hiemalis (n = 1×107) were inoculated in 50 ml of culture media in the presence of one of three carbon sources, namely, glucose, chicken oil waste, or fish oil waste, and cultivated at 28°C for 72h. The media included medium A containing exclusively a carbon and a nitrogen source and medium B containing a more limited nitrogen source than medium A. The fatty acid profiles of the lipids produced were determined by gas chromatography. The yield of lipid production was 33%, 66% and 68% in the glucose, chicken oil waste and fish oil waste, respectively, in medium B. The yield was higher than that in medium A because the limitation of nitrogen source in medium B would cause microorganism to reach the production phase in the logarithmic phase of growth more quickly. In addition, in medium B fatty acids, such as, for example, linoleic acid, were produced with glucose as the carbon source. Discussion and The findings show that using oil wastes, which are easily accessible and less expensive, could increase lipid production by Mucor hiemalis. Another advantage is production of valuable microbial lipids with a high essential unsaturated fatty acid content which has wide applications in the food industry. Furthermore, the data show that limitation of the nitrogen source has a significant effect on the production of microbial lipid by this fungus.