4 CONCLUSION
In conclusion, the feasibility of IUP was verified in E.coli ,
followed by serial optimization. To increase the titer of model
terpenoid, lycopene, PRha, RBS5 and type II IDI fromS. cerevisiae were screened for controlling IUP expression
cassette, ThiMEc and inter-converting of
IPP/DMAPP, respectively. The best concentration of IPTG, isopentenol’s
ratio and concentration was 0.005 mMol/L, prenol: isoprenol=1:3 and 2
g/L. The optimal strain harboring plasmid system produced 8.67
mg/OD600 lycopene titer. However, the plasmid loss was
observed over 50% in the third cultivation. In comparison, the strain
integrated 13 copy IUP expression cassettes in genome was constructed in
2 weeks, not only showing stability after 10 generations but also
producing higher lycopene titer (15.43 mg/OD600 by
fed-batch).