The Effect of Soybean Oil on Lipid Metabolism in Mucor circinelloides WJ11 by Metabolomic Analysis

Oleaginous fungus Mucor circinelloides utilizes different carbon sources associated with sustainable production of lipids, using soybean oil as carbon source, the fungus accumulated more intracellular lipids. Nonetheless, the metabolic changes in M. circinelloides upon vegetable oil as main carbon source have not been yet reported. Therefore, this study was conducted to investigate the metabolomics of M. circinelloides WJ11 cultivated in mixed glucose and soybean oil as carbon source and to reveal its effects on lipid metabolism. M. circinelloides strain WJ11 was cultured under optimized conditions in a fermenter and the biomass samples were collected after 24 h for lipid metabolite investigation. The frozen biomass samples were subjected to various chromatographic analyses like liquid chromatography mass spectrometry analysis and high resolution-mass spectrometry for metabolite profiling. A total of 438 differential metabolites were identified, of which 48 were up-regulated and 33 were down-regulated. Among them, lyso-phosphatidic acid and monoglyceride were up-regulated whereas phosphatidylglycerol and lyso-phosphatidylglycerol were down-regulated in the experimental group (soybean oil and glucose as mixed carbon sources) compared with the control group (glucose as single carbon source). Significant changes in metabolite levels correlated to lipid synthesis were identified. This study showed that the addition of soybean oil to the medium favors the triacylglycerol synthesis in M. circinelloides. Our results can also be applied to the investigation of other microorganisms and would contribute to further genetic engineering for higher lipid accumulation in fungi.