Screening of lipid high producing mutant from rhodotorula glutinis by low ion implantation and study on optimization of fermentation medium

In order to obtain lipid producing strain with high-yield, the wild type stain Rhodotorula glutinis was treated by low ion implantation, and optimization of fermentation medium for higher lipid yield was carried out using mutant strain. It was found that the strain had a higher positive mutation rate when the output power was 10 keV and the dose of N⁺ implantation was 80 × 2.6 × 10¹³ ions/cm². Then a high-yield mutant strain D30 was obtained through cid-heating coupling ultrasonic method and lipid yield was 3.10 g/L. Additionally, the surface response method was used to optimize fermentation medium. The three significant factors (glucose, peptone, KH₂PO₄) were optimized using response surface methodology (RSM), and the optimized parameters of fermentation medium were as follows: glucose 73.40 g/L, peptone 1.06 g/L and KH₂PO₄ 3.56 g/L. Finally the fermentation characteristic of high-yield mutation strain D30 was studied, when fermentation time was 10 days, which lipid yield increased to 7.81 g/L. Fatty acid composition of the lipid was determined by GC, and the most represented fatty acids of mutant D30 were C16:0 (11.4 %), C16:1 (5.66 %), C18:1 (49.3 %), and C18:2 (27.0 %).