DNA Research Advance Access originally published online on August 27, 2008
DNA Research 2008 15(5):277-284; doi:10.1093/dnares/dsn019
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Superpositioning of Deletions Promotes Growth of Escherichia coli with a Reduced Genome
1 Biofrontier Laboratories, Kyowa Hakko Kogyo Co. Ltd, 3-6-6 Asahimachi, Machidashi, Tokyo 194-8533, Japan
2 Department of Biological Sciences, Graduate Schools of Science and Engineering, Tokyo Metropolitan University, Minamiohsawa, Hachioji, Tokyo 192-0397, Japan
Received 18 December 2007 ; accepted 9 July 2008.
Escherichia coli has dispensable genome regions and eliminating them may improve cell use by reducing unnecessary metabolic pathways and complex regulatory networks. Although several strains with reduced genomes have already been constructed, there have been no reports of strains constructed with deletions assayed for influence on growth. To retain robust growth and fundamental metabolic pathways, the growth of each deletion strain and combination effects of deletions were checked using M9 minimal medium. Then a new strain, MGF-01, with a 1 Mb reduced genome was constructed by integrating deletions that did not affect growth. MGF-01 grew as well as the wild type in the exponential phase and continued growing after the wild type had entered the stationary phase. The final cell density of MGF-01 was 1.5 times higher than that of the wild-type strain. Using MGF-01 as a production host, a 2.4-fold increase in L-threonine production was achieved.
* To whom correspondence should be addressed. Tel. +81 42-725-2555. Fax. +81 42-726-8330. E-mail: mizoguchi.hiroshi{at}kyowa.co.jp (hiroshi.mizoguchi{at}kyowa-kirin.co.jp), hmori{at}kyowa.co.jp (hideo.mori{at}kyowa-kirin.co.jp)