Engineering E. coli for high-specificity production of C5 alcohols isoprenol and prenol for biofuels
Researchers in China have engineered the bacteria Escherichia coli for the high-specificity production of the C5 alcohols isoprenol and prenol as next-generation biofuels. An open access paper on their work is published in the journal Biotechnology for Biofuels. “To the best of our knowledge,” they wrote, “this is the first successful report on high-specificity production of isoprenol and prenol by microbial fermentation.”
C5 alcohols have higher energy density and lower water miscibility than ethanol, a C2 alcohol. In addition, the branched-chain unsaturated isopentenols (isoprenol and prenol) possess higher octane numbers and better low-temperature fluidity than their straight-chain saturated counterpart, the authors note.
However, the isoprenol and prenol, which are conventionally manufactured from petroleum-derived isobutene and formaldehyde, are not compounds largely accumulated in natural organism. The need for the next generation of biofuels with better physical and chemical properties impels us to seek a biological route for direct production of isopentenols from renewable sugar in a microbial fermentation process.—Zheng et al.
In the study, the team used the heterogenous mevalonate-dependent (MVA) isoprenoid pathway for the synthesis of isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP) intermediates, and then converted IPP and DMAPP to isoprenol and prenol, respectively.
Ultimately, they obtained 1.3 g/L single isoprenol and 0.2 g/L ~80% prenol. A maximal yield of 12% was achieved in both isoprenol- and prenol-producing strains.
Yanning Zheng, Qiang Liu, Lingling Li, Wen Qin, Jianming Yang, Haibo Zhang, Xinglin Jiang, Tao Cheng, Wei Liu, Xin Xu and Mo Xian (2013) Metabolic engineering of Escherichia coli for high-specificity production of isoprenol and prenol as next generation of biofuels. Biotechnology for Biofuels 6:57 doi: 10.1186/1754-6834-6-57