Breeding Of Oleaginous Yeast And Researching For Conditions Of Fermentation

Currently, with the growing population, demand of oil is increasing sharply, fats and oils can not meet human needs. With the increasing scarcity of oil resources, rising oil prices and the growing oil supply and demand and environmental pollution problems appear more prominent, multi-channel development of renewable oil resources become a necessity. Microbial oil is the another second after the animal and vegetable fats to develop new oil resources, it is the development of high quality raw material of biodiesel, most of them can reduce the serum cholesterol-rich fatty acids, it has an important role in promoting human health. Therefore, microbial oil resources development and utilization of biodiesel and food health has practical significance.With the oleaginous yeast Y1 for the experiment, Single factor experiments and orthogonal experiment in shake flask production of liquid fermentation medium was optimized resin. The Optimal medium composition is glucose 85, peptone 40, (NH₄)₂SO₄ 10,MgSO₄·7H₂O 0.3,Na₂HPO₄ 3,KH₂PO₄ 2.5. Volume of 100ml shake flask is 30 ml, Seed inoculation of liquid is 10%,Shaking speed is 160 r/min, Temperature is 28℃, the cell biomass of oleaginous yeast Y1 is 20.25g/L,the cell biomass was increased by 46.5% before the optimization. Through different concentrations of carbon source in fermentation of lipid culture, the maximum of cell biomass is in 21.5h. The growth curves of oleaginous yeast Y1 are achieved by three different ways, exponential phase of growth is in 4～24h,stationary phase of growth is in 24～68h.Two mutant strains Y13 and Y9 are achieved by microwave and UV mutagenesis. The oil production of Y13 is 4.39g/L, the oil content of Y13 is 22.09%. The oil production of Y9 is 5.25g/L, the oil content of Y9 is 23.85%,then choosing Y9 as Y1m after the mutagenesis.In the two-step fermentation process, adjustment of the fermentation medium composed of glucose 85g/L, peptone 1.5g/L,(NH₄)₂SO₄ 10g/L, MgSO₄·7H₂O 0.3g/L, Na₂HPO₄ 3g/L, KH₂PO₄ 2.5g/L, ZnSO₄ 0.5mg/L, CaCl₂ 0.3mg/L, FeCl₃ 0.5mg/L, CuSO₄ 0.5mg/L, access in the optimized medium for the initial 24h of Y1m cell, adjusting the initial pH value of 6.0, liquid volume 100ml in 500ml flask, 27℃,160r/min, keep constant temperature shaking in 6d, the The biomass of mixed strains is 22.24g/L, oil production is 8.04g/L, oil content of 36.15%.