Breeding high-yield oil-producing strain to use cheap carbon source by UV induced protoplast mutagenesis

Abstract:

[Objective] We used UV induced protoplast mutagenesis to study breed a new high-yielding lipid-producing strain which could use cheap carbon source. [Methods] Get the 1.5% glusulase and 1.0% cellulose solution. Hydrolyze to remove the cell wall and obtain the protoplast of 2A00015 (Candida parapsilosis). Put it under the ultraviolet lamp for mutagenesis and cultivate regenrated wall. Then screen to get the high oil generated yeast which could be fermented by low-cost carbon source. Determine its fat acid components by gas chromatography with mass spectrometric (GC-MS). [Results] Cultivated the mutant strain with best mutation 2A00015/25 in the glucose. We found that the biomass, oil yield rate and oil production are separately 17.77 g/L, 58.12% and 10.32 g/L, which are separately 12.45%, 23.32% and 38.68% higher than the original strain. We have also cultivated the mutant strain in the waste molasses and found the biomass, oil yield rate and oil production are separately 18.54 g/L, 49.44% and 9.17 g/L, which are separately 9.09%, 21.16% and 32.18% higher than the original strain. The oil yield rate is lower in the waste molasses cultivation than that in glucose cultivation. However, in consideration of environment protection and cost of raw materials, the waste molasses is of much more advantages. It is tested that the fat generated from the waste molasses fermentation consists of eight kinds of fat acid. Its fat acid components are similar to the vegetable oil, in which the content of unsaturated fatty acid comprised 82.4% of the total fatty acid. [Conclusion] Basing on UV induced protoplast mutagenesis, we have successfully bred a new high-yielding oil strain which can make use of the low-cost carbon source, with its oil production rate 49.4% which has increased by 21.2%.