RRC ID 35374
Author Reyes LH, Almario MP, Kao KC.
Title Genomic library screens for genes involved in n-butanol tolerance in Escherichia coli.
Journal PLoS One
Abstract BACKGROUND:n-Butanol is a promising emerging biofuel, and recent metabolic engineering efforts have demonstrated the use of several microbial hosts for its production. However, most organisms have very low tolerance to n-butanol (up to 2% (v/v)), limiting the economic viability of this biofuel. The rational engineering of more robust n-butanol production hosts relies upon understanding the mechanisms involved in tolerance. However, the existing knowledge of genes involved in n-butanol tolerance is limited. The goal of this study is therefore to identify E. coli genes that are involved in n-butanol tolerance.
METHODOLOGY/PRINCIPAL FINDINGS:Using a genomic library enrichment strategy, we identified approximately 270 genes that were enriched or depleted in n-butanol challenge. The effects of these candidate genes on n-butanol tolerance were experimentally determined using overexpression or deletion libraries. Among the 55 enriched genes tested, 11 were experimentally shown to confer enhanced tolerance to n-butanol when overexpressed compared to the wild-type. Among the 84 depleted genes tested, three conferred increased n-butanol resistance when deleted. The overexpressed genes that conferred the largest increase in n-butanol tolerance were related to iron transport and metabolism, entC and feoA, which increased the n-butanol tolerance by 32.8±4.0% and 49.1±3.3%, respectively. The deleted gene that resulted in the largest increase in resistance to n-butanol was astE, which enhanced n-butanol tolerance by 48.7±6.3%.
CONCLUSIONS/SIGNIFICANCE:We identified and experimentally verified 14 genes that decreased the inhibitory effect of n-butanol tolerance on E. coli. From the data, we were able to expand the current knowledge on the genes involved in n-butanol tolerance; the results suggest that an increased iron transport and metabolism and decreased acid resistance may enhance n-butanol tolerance. The genes and mechanisms identified in this study will be helpful in the rational engineering of more robust biofuel producers.
Volume 6(3)
Pages e17678
Published 2011-3-8
DOI 10.1371/journal.pone.0017678
PMID 21408113
PMC PMC3050900
MeSH 1-Butanol / pharmacology* Adaptation, Physiological / drug effects Adaptation, Physiological / genetics* Cell Membrane / drug effects Cell Membrane / genetics Comparative Genomic Hybridization Escherichia coli / drug effects* Escherichia coli / genetics* Escherichia coli / growth & development Gene Expression Profiling Gene Knockout Techniques Genes, Bacterial / genetics* Genetic Testing* Genomic Library* Kinetics Molecular Sequence Annotation
IF 2.74
Times Cited 89
Prokaryotes E. coli ME9062(BW25113) Keio collection ASKA collection