Effect of crude glycerol impurities on lipid preparation by Rhodosporidium toruloides yeast 32489

•Crude glycerol as a carbon source was applied for lipid preparation.•Influences of four types of impurity on lipid preparation were investigated.•Methanol existed in crude glycerol inhibited the metabolism of oleaginous yeast.•Inhibition was offset with sodium oleate, methyl oleate and NaCl impurity. Crude glycerol (byproduct of biodiesel preparation) was utilised as the carbon source to produce lipid using oleaginous yeast Rhodosporidium toruloides 32489. Under the same conditions, lipid production with crude glycerol was higher than those produced with glucose and pure glycerol. The effects of 4 main impurities in crude glycerol (methyl oleate, sodium oleate, NaCl and methanol) on lipid production were investigated. Compared with utilising pure glycerol, addition of methyl oleate, sodium oleate, and NaCl impurities increased lipid production by 47.0%, 68.0% and 64.0%, respectively, while methanol decreased lipid production by 17.7%. However, when methanol was mixed with other impurities, its inhibition effect was alleviated due to the promoting effect of other impurities. Hence, crude glycerol could be used as a renewable and low-cost carbon source to replace pure glucose or glycerol for lipid preparation.