Efficient production of lycopene by engineered E. coli strains harboring different types of plasmids

The lycopene biosynthetic genes crtE, crtB, and crtI from Deinococcus wulumuqiensis R12 were integrated into three different vector backbones-pET28a, pTrc99A, and pUC18-and the resulting recombinant plasmids pET28a-EBI, pTrc99A-EBI, and pUC18-EBI were introduced into different Escherichia coli hosts. The results showed that lycopene production of strain 28BL was lower than that of 99 series strains without IPTG in LB medium. In addition, lycopene production of 99JM with supplementation of 20% (w/v) glycerol was 1.6-fold higher than with supplementation of 6% (w/v) glucose. After optimization of the host strain and culture medium, the yield of microbial lycopene was increased successfully. When recombinant E. coli 99DH was cultivated under exposure to light in 2YT + Gly medium, the highest lycopene production rate was 26.2 mg/L/h at 30 h, and the maximum specific lycopene content was 67 mg/g dry cell (925 mg/L) at 40 h, which represents a 76% increase over the starting point.