Isobutanol production at elevated temperatures in thermophilic Geobacillus thermoglucosidasius.
The potential advantages of biological production of chemicals or fuels from biomass at high temperatures include reduced enzyme loading for cellulose degradation, decreased chance of contamination, and lower product separation cost. In general, high temperature production of compounds that are not native to the thermophilic hosts is limited by enzyme stability and the lack of suitable expression systems. Further complications can arise when the pathway includes a volatile intermediate. Here we report the engineering of Geobacillus thermoglucosidasius to produce isobutanol at 50°C. We prospected various enzymes in the isobutanol synthesis pathway and characterized their thermostabilities. We also constructed an expression system based on the lactate dehydrogenase promoter from Geobacillus thermodenitrificans. With the best enzyme combination and the expression system, 3.3g/l of isobutanol was produced from glucose and 0.6g/l of isobutanol from cellobiose in G. thermoglucosidasius within 48h at 50°C. This is the first demonstration of isobutanol production in recombinant bacteria at an elevated temperature.
Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, USA.
Paul P
PP
Lin
Division of Chemistry and Chemical Engineering, California Institute of Technology, Mail Code 210-41, Pasadena, CA 91125, USA.
Kersten S
KS
Rabe
Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, USA.
Jennifer L
JL
Takasumi
Division of Chemistry and Chemical Engineering, California Institute of Technology, Mail Code 210-41, Pasadena, CA 91125, USA.
Marvin
M
Kadisch
Division of Chemistry and Chemical Engineering, California Institute of Technology, Mail Code 210-41, Pasadena, CA 91125, USA.
Frances H
FH
Arnold
Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, USA. Electronic address: liaoj@seas.ucla.edu.
James C
JC
Liao
D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D018533:Biomass; D000440:Butanols / Q000378:metabolism*; D002475:Cellobiose / Q000378:metabolism*; D056506:Geobacillus / Q000235:genetics / Q000254:growth & development*; D006358:Hot Temperature; D007770:L-Lactate Dehydrogenase / Q000096:biosynthesis / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics
D001426:Bacterial Proteins; D000440:Butanols; D011994:Recombinant Proteins; D002475:Cellobiose; C040507:isobutyl alcohol; D007770:L-Lactate Dehydrogenase
Biofuel; Butanol; Metabolic engineering; Thermophile