Recombination Of Heterologous Modules For Improving Biosynthesis Of Astaxanthin In Yeast

Astaxanthin is a kind of tetraterpene with strong antioxygenic property.Concerning the safety and economy issue the biosynthesis of astaxanthin has greater potential than chemical synthesis and extraction from natural producers.In order to improve the synthesis of astaxanthin in Saccharomyces cerevisiae,the combination of?-carotene hydroxylase(crtZ)and ?-carotene ketolase(crtW)was optimized in this study.The work of this paper is summarized as follows.1.We introduced the crtZ from Agrobacterium aurantiacum and the crtW from Brevundimonas vesicularis DC263 into the high-yield ?-carotene Saccharomyces cerevisiae,and obtained the astaxanthin producing Saccharomyces cerevisiae strain Sy BE?Sc5010005,as a chassis strain.Then in vitro recombination of crtZ and crtW gene modules from different biological sources was realized by using in vitro Sc Ra Mb LE.The strain Sy BE?Sc5010032 with 8.51-fold increase of astaxanthin yield was obtained.And the heterologous gene introduced by the in vitro recombination was the single copy crtW from Brevundimonas vesic?Laris DC263.2.Based on the homologous recombination ability of Saccharomyces cerevisiae,crtZ and crtW from different biological sources were integrated into Ty1 sites of chassis strain's genome,randomly.Finally,strain Sy BE?Sc5010065 was obtained with astaxanthin yield increased 9.71-fold.And the heterologous genes introduced by in vivo recombination method were crtZ from Agrobacterium aurantiacum and crtW from Alcaligenes sp.strain.3.The transformation efficiency,strain stability and astaxanthin accumulation process of the in vitro and in vivo recombination methods were compared in this paper.The results showed that the efficiency and stability of the in vivo recombination were better than in vitro recombination.