BioChem - DOS

Elevated β-carotene synthesis by the engineered Rhodobacter sphaeroides with enhanced CrtY expression

Journal of agricultural and food chemistry

Qiang, Shan; Su, An Ping; Li, Ying; Chen, Zhi; Hu, Ching Yuan; Meng, Yong Hong

<P>&beta;-Carotene is a precursor of vitamin A and a dietary supplement for its antioxidant property. Producing &beta;-carotene by microbial fermentation has attracted much attention owing to consumers’ preference for the natural product. In this study, an engineered photosynthetic <I>Rhodobacter sphaeroides</I> producing &beta;-carotene was constructed by the following strategies: (1) five promoters of different strengths were used to investigate the effect of the expression level of <I>crtY</I> on &beta;-carotene content. It was found that P<I><SUB>rrnB</SUB></I> increased the &beta;-carotene content by 109%. (2) blocking of the branched pentose phosphate pathway by <I>zwf</I> deletion, and (3) overexpressing <I>dxs</I> could restore the transcriptional levels of <I>crtE</I> and <I>crtB</I>. Finally, the engineered RS-C3 has the highest &beta;-carotene content of 14.93 mg/g dry cell weight (DCW) among all of the reported photosynthetic bacteria and the &beta;-carotene content reached 3.34 mg/g DCW under light conditions. Our results will be available for industrial use to supply a large quantity of natural &beta;-carotene.</P><BR>[FIG OMISSION]</BR>

2019

American Chemical Society

0021-8561

1520-5118

67

34

pp.9560-9568

10.1021/acs.jafc.9b02597

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART97827968

photosynthetic bacteria; Rhodobacter sphaeroides; β-carotene; crtY gene; promoters