Background: sp. PCC 6803 is an attractive organism for the production of alcohols, such as isobutanol and ethanol. However, because stress against the produced alcohol is a major barrier for industrial applications, it is highly desirable to engineer organisms with strong alcohol tolerance.
Results: Isobutanol-tolerant strains of sp. PCC 6803 were obtained by long-term passage culture experiments using medium containing 2 g/L isobutanol. These evolved strains grew on medium containing 5 g/L isobutanol on which the parental strain could not grow. Mutation analysis of the evolved strains revealed that they acquired resistance ability due to combinatorial malfunctions of slr1044 () and slr0369 (), or slr0322 () and . The tolerant strains demonstrated stress resistance against isobutanol as well as a wide variety of alcohols such as ethanol, -butanol, and isopentanol. As a result of introducing an ethanol-producing pathway into the evolved strain, its productivity successfully increased to 142% of the control strain.
Conclusions: Novel mutations were identified that improved the stress tolerance ability of various alcohols in sp. PCC 6803.
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http://dx.doi.org/10.1186/s13068-017-0996-5 | DOI Listing |
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Technische Universität Berlin, Institute of Chemistry PC 14, Straße des 17. Juni 135, 10623 Berlin, Germany. Electronic address:
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National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China. Electronic address:
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