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Title: Engineering global transcription factor cyclic AMP receptor protein of Escherichia coli for improved 1-butanol tolerance
Authors: Zhang, Hongfang
Chong, Huiqing
Ching, Chi Bun
Song, Hao
Jiang, Rongrong
Keywords: DRNTU::Engineering::Chemical engineering::Biotechnology
Issue Date: 2012
Source: Zhang, H., Chong, H., Ching, C. B., Song, H.,& Jiang, R. (2012). Engineering global transcription factor cyclic AMP receptor protein of Escherichia coli for improved 1-butanol tolerance. Applied Microbiology and Biotechnology, 94(4), 1107-1117.
Series/Report no.: Applied microbiology and biotechnology
Abstract: One major challenge in biofuel production, including biobutanol production, is the low tolerance of the microbial host towards increasing biofuel concentration during fermentation. Here, we have demonstrated that Escherichia coli 1-butanol tolerance can be greatly enhanced through random mutagenesis of global transcription factor cyclic AMP receptor protein (CRP). Four mutants (MT1–MT4) with elevated 1-butanol tolerance were isolated from error-prone PCR libraries through an enrichment screening. A DNA shuffling library was then constructed using MT1–MT4 as templates and one mutant (MT5) that exhibited the best tolerance ability among all variants was selected. In the presence of 0.8 % (v/v, 6.5 g/l) 1-butanol, the growth rate of MT5 was found to be 0.28 h−1 while that of wild type was 0.20 h−1. When 1-butanol concentration increased to 1.2 % (9.7 g/l), the growth rate of MT5 (0.18 h−1) became twice that of the wild type (0.09 h−1). Microbial adhesion to hydrocarbon test showed that cell surface of MT5 was less hydrophobic and its cell length became significantly longer in the presence of 1-butanol, as observed by scanning electron microscopy. Quantitative real-time reverse transcription PCR analysis revealed that several CRP regulated, 1-butanol stress response related genes (rpoH, ompF, sodA, manX, male, and marA) demonstrated differential expression in MT5 in the presence or absence of 1-butanol. In conclusion, direct manipulation of the transcript profile through engineering global transcription factor CRP can provide a useful tool in strain engineering.
DOI: 10.1007/s00253-012-4012-5
Fulltext Permission: none
Fulltext Availability: No Fulltext
Appears in Collections:SCBE Journal Articles

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