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High growth rate and substrate exhaustion results in rapid cell death and lysis in the thermophilic bacterium Geobacillus thermoleovorans

Biomedical Sciences Research Institute Computer Science Research Institute Environmental Sciences Research Institute Nanotechnology & Advanced Materials Research Institute

Pavlostathis, Spyros G., Marchant, Roger, Banat, Ibrahim, Ternan, Nigel and McMullan, Geoffrey (2006) High growth rate and substrate exhaustion results in rapid cell death and lysis in the thermophilic bacterium Geobacillus thermoleovorans. BIOTECHNOLOGY AND BIOENGINEERING, 95 (1). pp. 84-95. [Journal article]

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URL: http://www3.interscience.wiley.com/journal/112608103/abstract

DOI: 10.1002/bit.20962

Abstract

Batch cultures of the thermophilic bacterium Geobacillus thermoleovorans T80 attained extremely high-specific glucose utilization rates leading to high specific growth rates, followed by extensive cell death and lysis with the onset of substrate exhaustion. The dramatic decrease in live cell numbers, as determined by flow cytometry, was accompanied by the release of soluble protein. Once the growth phase reached the point of commitment to lysis created by the impending exhaustion of substrate, the addition of extra carbon substrate did not halt the rapid death rate and lysis, although, towards the end of the exponential growth phase, the substrate was utilized producing only a small additional biomass concentration as a result of the net effect of cell growth and death. This lytic phenomenon was observed when a range of different carbon substrates (glucose, pyruvate, acetate, n-hexadecane, nutrient broth), as well as ammonium (the nitrogen source) in the presence of excess carbon source, reached near exhaustion. The rate and extent of cell death and the ensuing lysis depend on the culture growth rate. Cultures batch grown with a lower initial substrate concentration, or at a lower temperature, or at lower dilution rates for continuous-flow cultures, exhibited a lower rate and extent of cell death and lysis. Batch re-culture of the persister cells resulted in a behavior identical to that of the original culture indicating that these cells were not genetically modified. The glucose utilization, cell growth and death rates were mathematically described based on Monod kinetics and estimated values of pertinent biokinetic constants are reported. (c) 2006 Wiley Periodicals, Inc.

Item Type:Journal article
Faculties and Schools:Faculty of Life and Health Sciences
Faculty of Life and Health Sciences > School of Biomedical Sciences
Research Institutes and Groups:Biomedical Sciences Research Institute
Biomedical Sciences Research Institute > Northern Ireland Centre for Food and Health (NICHE)
Biomedical Sciences Research Institute > Pharmaceutical Science and Practice
ID Code:3677
Deposited By:Dr Nigel Ternan
Deposited On:17 Dec 2009 14:06
Last Modified:16 May 2012 15:06

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