Analysis of the mechanism and regulation of lactose transport and metabolism in Clostridium acetobutylicum ATCC 824.

Yu, Yang, Tangney, Martin, Aass, Hans C and Mitchell, Wilfred J (2007) Analysis of the mechanism and regulation of lactose transport and metabolism in Clostridium acetobutylicum ATCC 824. Applied and Environmental Microbiology, 73 (6). pp. 1842-1850. ISSN 0099 2240

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Although the acetone-butanol-ethanol (ABE) fermentation of Clostridium acetobutylicum is currently uneconomic, the ability of the bacterium to metabolise a wide range of carbohydrates offers the potential for revival based on the use of cheap, low grade substrates. We have investigated the uptake and metabolism of lactose, the major sugar in industrial whey waste, by C. acetobutylicum ATCC 824. Lactose is taken up via a phosphoenolpyruvate (PEP)-dependent phosphotransferase system (PTS) comprising both soluble and membrane-associated components, and the resulting phosphorylated derivative is hydrolysed by a phospho--galactosidase. These activities are induced during growth on lactose, but are absent in glucose-grown cells. Analysis of the C. acetobutylicum genome sequence identified a gene system, lacRFEG, encoding a transcriptional regulator of the DeoR family, IIA and IICB components of a lactose PTS, and phospho--galactosidase. During growth in medium containing both glucose and lactose, C. acetobutylicum exhibited a classical diauxic growth, and the lac operon was not expressed until glucose was exhausted from the medium. The presence upstream of lacR of a potential catabolite responsive element (cre) encompassing the transcriptional start site is indicative of the mechanism of carbon catabolite repression characteristic of low-GC Gram-positive bacteria. A pathway for the uptake and metabolism of lactose by this industrially important organism is proposed.

Item Type: Article
Print ISSN: 0099 2240
Uncontrolled Keywords: Lactose transport; Clostridium acetobutylicum;
University Divisions/Research Centres: School of Life, Sports & Social Sciences (from 1st August 2015)
Dewey Decimal Subjects: 500 Science > 570 Life sciences; biology > 579 Microorganisms, fungi & algae
Library of Congress Subjects: Q Science > QR Microbiology
Item ID: 1725
Depositing User: RAE Import
Date Deposited: 01 Feb 2008 16:33
Last Modified: 05 Jul 2016 16:55

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