Engineering alternative butanol production platforms in heterologous bacteria.
Alternative microbial hosts have been engineered as biocatalysts for butanol biosynthesis. The butanol synthetic pathway of Clostridium acetobutylicum was first re-constructed in Escherichia coli to establish a baseline for comparison to other hosts. Whereas polycistronic expression of the pathway genes resulted in the production of 34 mg/L butanol, individual expression of pathway genes elevated titers to 200 mg/L. Improved titers were achieved by co-expression of Saccharomyces cerevisiae formate dehydrogenase while overexpression of E. coli glyceraldehyde 3-phosphate dehydrogenase to elevate glycolytic flux improved titers to 580 mg/L. Pseudomonas putida and Bacillus subtilis were also explored as alternative production hosts. Polycistronic expression of butanol biosynthetic genes yielded butanol titers of 120 and 24 mg/L from P. putida and B. subtilis, respectively. Production in the obligate aerobe P. putida was dependent upon expression of bcd-etfAB. These results demonstrate the potential of engineering butanol biosynthesis in a variety of heterologous microorganisms, including those cultivated aerobically.
Nielsen
David R
DR
Department of Chemical Engineering, 77 Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Leonard
Effendi
E
Yoon
Sang-Hwal
SH
Tseng
Hsien-Chung
HC
Yuan
Clara
C
Prather
Kristala L Jones
KL
D001412:Bacillus subtilis / Q000235:genetics / Q000378:metabolism; D000440:Butanols / Q000378:metabolism*; D046969:Clostridium acetobutylicum / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005818:Genetic Engineering / Q000379:methods*; D024861:Genetic Enhancement / Q000379:methods*; D005986:Glyceraldehyde 3-Phosphate / Q000235:genetics; D015202:Protein Engineering / Q000379:methods*
D000440:Butanols; D029968:Escherichia coli Proteins; D005986:Glyceraldehyde 3-Phosphate