Screening Special Phenotype Strains For Production Of Lipid And Carotenoid In Rhodosporidium Haploides By Mutagenesis

Taking advantage of renewable resource to develop energy production, environmental-friendly material has become a hot topic in the world with shortage of energy supply situation, serious environment pollution and abnormal climate change. Therefore, the development of biological energy and other new energy technology is an important approach to realize sustainable development. Microbial lipids have a great potential as a feedstock for biodiesel. Microbial lipid is an important development direction because of its short production cycle, continuous operation feature.In this experiment, Rhodosporidium haploid was treated as the origin strain to produce lipid and carotenoid. Atmospheric and room temperature plasma(ARTP) and nitrosoguanidine(NTG) were used to screen special phenotype strains in order to research the relationship between lipid content and carotenoid content. After compound mutagenesis, five strains were obtained and named as XP-1、XR-2、XO-3、XY-4 and XW-5. Lipid and carotenoid were extracted from them. In all of strains,the production of carotenoid in XR-2 was the highest, however, its lipid content was the lowest. The other special phenotype strains’ carotenoid content decreased and lipid content had no obvious change. The results indicated that decline of carotenoid hadn’t affect on lipid accumulation. Thus. descending lipid content could promote the synthesis of carotenoid.XR-2 had lower biomass. For the sake of obtaining more biomass, culture conditions of XR-2 was optimized and carotenoid and lipid were measured in the process of optimization. Different nutrients were added into nitrogen-limited medium when XR-2 was cultivated. Amino acid, vitamins and mixture of both were added into medium to make the strain grow better. The experiment indicated that p-Amino benzoic acid made biomass and lipid of XR-2 increase, reaching 7.3 g/L, 37%(g/g) respectively. Lipid content was 1.6 folders higher than the original strain. Trytophan also made biomass increase, but content of carotenoid decreased.We took SNP sequencing for five strains at the same time. The reason of the special phenotype of XP-1, XO-3, XY-4 was that carotenoid synthetic pathway of key genes were mutanted. CRT1 was mutanted in XO-3 and XY-4, PSY1 was mutanted in XP-1, FAS2 was mutanted in XR-2, the XW-5’ key gene ACS1 made change.