The Construction Of Astaxanthin High-producing Saccharomyces Cerevisiae Based On In Vitro Gene Rearrangement And Plasma Mutant

Astaxanthin has strong antioxidant ability,and its antioxidant capacity is 100 times than vitamin E.It is widely used in fields including nutrition and health care products,cosmetics,food and aquaculture.Due to the safety problems of chemical synthesis and the cost of extraction,biosynthetic astaxanthin has a wide application prospect.To improve the production of astaxanthin in Saccharomyces cerevisiae,the following works have done in this study:(1)This study focuses on investigating the substrate preference of β-carotene ketoenzyme and hydroxylase.The results showed that β-carotene ketoenzyme from Brevundimonas vesicularis DC263(BDC263 CrtW)prefered to β-carotene as a substrate and β-carotene hydroxylase from Agrobacterium aurantiacum(Aa CrtZ)prefered to canthaxanthin as a substrate.(2)Based on the differences in catalytic efficiency and adaptability of ketoenzyme(CrtW)and hydroxylase(CrtZ)from different sources,7 kinds of CrtZs and 7 kinds of CrtWs were rando mLy combinated by gene rearrangement method in vitro,and the strain SyBE_Sc211S06 was obtained which astaxanthin production is 1.8 times than the original strain(from 1.4 mg/g DCW to 2.5 mg/g DCW).(3)A high-yield astaxanthin mutant SyBE_Sc2110M3 with good growth and genetic stability is obtained by atmospheric and room temperature plasma(ARTP),which was 1.6 times than original strain on the production of astaxanthin.At the same time,a mutant SyBE_Sc2110M1 with a 20 times increase in lycopene accumulation was obtained.Whole genome resequencing results showed that the chromosomes 12 and 13 of the two strains showed 200 kb large fragment repeat,and the genes of the repeated fragments were analyzed to find that ERG13,HMG1 and GRC3 were related to astaxanthin biosynthesis.Then,analysis of SNP/InDel mutation suggesting that the reason of astaxanthin yield differences between two strains may be ASG1、YBR012WB、YLR410W-B.