Screening Of Strain With High-yield Oil

At present, animal and vegetable oil can not meet the demands of people with the development of population. As a rusult, contradiction between oil demand and the natural resource shortage is serious day by day. Under the situation, opening a new oil source - microorganism oil has the important theory and the practical meaning. A lot of microbial oil is rich in polyunsaturated fatty acids and they play an important role in the health of human being. The exploitation of microbial oil can ease the situation of shortage of animal and vegetable oil resource, which provide a new way of the oil resourceNow, research and development of microorganism oil were concentrated to produce special application functionality oil with high added value using microorganism which can produce lipid with variety unsaturated fatty acid. For example, monounsaturated fatty acids, such as palmitoleic acid,oleic acid and so on; polyunsaturated fatty acid, such as linoleic acid (LA),linolenic Acid (LNA) arachidonic acid(AA),eicosapentaenoic acid(EPA),docosahexenoic acid (DHA) and so on. These functionality lipids with special function and utility has more and more vital role in promoting the human health aspect.Microbial lipid have many advantages, such as short life cycle, less labor required, less affection by venue, season and climate, and easier to scale up. However, microbial lipid also has its limitation, and the most obvious aspect is the lower yield of lipid. In order to improve yield, this article has done the research work as follows:1. Breeding strains with high-yield of oilsIn order to improve oil yield of Rhodotorula glutinis 31596, some mutation methods, such as low-energy ion implantation mutation,UV mutation and microwave mutation, were used to screen high-yield oil strains. Finally, one strain D30 was obtained through interview screening and senior screening. The oil yield of mutation was reached 3.10 g/L and improved by 33.05 % compared with original strain. It's production characteristic had no significant change through successive transfer of culture. And it was found that genetic characteristics of D30 were rather stable. Some method, such as sudan black B staining,soxhlet extraction method and acid-heating+ultrasonic extraction, were compared in the study of screening process. As a result, sudan black B staining was chosen as optimal qualitative interview screening method, and acid-heating+ultrasonic extration was chosen as optimal quantification senior screening method.2. Optimization of oil producing medium In order to improve production of D30, single factor and Box-Behnken experimental design were employed to optimize fermentation medium components of Rhodotorula glutinis, the results as follows(g/L): glucose 73.40 g/L, KH2PO4 3.56 g/L, peptone1.06 g/L; Under the optimized condition, , the oil yield of Rhodotorula glutinis reach as high as 3.49 g/L and increased by 12.58% when the fermentation time is 96 h.3. Additionally, the fermentation characteristic of high-yield mutation strain D30 was studied, it's lipid yield and biomass respectively increased to 7.81 g/L and 47.98 g/L(wet strain) , when fermentation time reach 10d.