| Squalene is an open-chain triterpenoid compound,which has important applications in the fields of medicine and food because of its special physiological functions.Thraustochytrium is a kind of marine fungal microorganism.It is considered to be a potential microorganism for industrial production of squalene because of its easy cultivation and fast growth.At present,the research on nutritional requirement and culture condition optimization of squalene-producing by thraustochytrium has become a hotspot at home and abroad,but the information on transcriptome of squalene-producing by thraustochytrium is still scarce.In this paper,Thraustochytrium sp.26185 was used as the starting strain to explore the external conditions and nutritional requirements affecting squalene production.At the transcriptome level,the mechanism of squalene synthesis by Amystrophyta was preliminarily explored.The specific research contents and results are as follows.(1)Through single factor experiments on carbon source,nitrogen source,magnesium sulfate,sodium chloride,temperature and inoculation amount,it was found that the squalene yield of strain reached 97 mg/L and 168 mg/L respectively under the optimized glucose concentration of 30 g/L and yeast powder concentration of 5 g/L.especially when the concentration of sodium chloride reached 5 g/L,the squalene yield reached 405.4 mg/L.Fermentation under single-factor optimization conditions yielded 420 mg/L.(2)On the basis of single factor experiments,squalene production was further optimized.The factors affecting squalene yield were screened by orthogonal experiment,and the optimum medium combination was selected.Result: The order of influence of three factors on squalene yield was sodium chloride > glucose > yeast extract.The optimum medium ratio was 30 g/L of glucose,2.5 g/L of yeast extract and 5 g/L of sodium chloride.The maximum yield was 456 mg/L.(3)The influencing factors of squalene production: concentration of sodium chloride was deeply analyzed.The control group(25 g/L)and the experimental group(5 g/L)were set up to annotate the related genes in squalene synthesis pathway by Illumina sequencing technology for the first time.At the same time,the differential genes between samples were obtained by statistical gene expression.To explore the influence of gene differential expression in different metabolic pathways on squalene synthesis by correlation analysis,and to provide a basis for elucidating the molecular mechanism of squalene synthesis.In summary,the squalene production by Thraustochytrium sp.26185 was optimized,and the squalene production was significantly increased.The synthesis mechanism of squalene was preliminarily studied by transcriptome studies. |
