Environmental Genomics of Barotolerant Marine Bacteria: Is Barotolerance an Ecologically Meaningful Phenotype?
J Grant Burgess, *David Brunton, 1H Takano and 1Phillip C Wright
Department of Biological Sciences and 1Department of Mechanical and Chemical Engineering, Heriot-Watt University, Edinburgh EH14, 4AS, UK.
Very little is known about the variety and distribution of barotolerant bacteria in ambient or low pressure habitats. This is because the majority of studies to date have been carried out on barophilic / deep sea isolates. However, barotolerant marine bacterial strains appear to be relatively widespread and have been isolated from shallow marine environments and a wide variety of specific ecological niches not associated with high hydrostatic pressures. Epibiotic biofilm-associated bacterial strains were shown to exhibit a higher survival rate in comparison to open water isolates during pressurisation within a novel high-pressure bioreactor. The strains were subjected to hydrostatic pressures of 55.5 MPa and 120 MPa and survival rates calculated. In addition, flow through, continuous high pressure studies were initiated to monitor the effect of pressure fluctuation of survival. A marine bacterial strain isolated from the surface of the marine brown alga Fucus sp. was found to demonstrate the highest level of barotolerance of the isolates examined. 16S rRNA gene analysis was performed and the taxonomy and distribution of these isolates are discussed. A program of environmental genomics using recognised signature sequences from barophilic / barotolerant bacteria has been used to monitor genotype distribution in environmental DNA samples. In addition to their identity and distribution, we will use barotolerant marine bacteria to produce industrial / biomedically useful products such as antibiotics [1] and enzymes and are developing novel bioreactor systems to this end [2].
[1] Burgess, J.G., Boyd, K.G. and Mearns-Spragg, A. (1999) Microbial antagonism: a neglected avenue of natural products research. Journal of Biotechnology, 1999, 70, 27-32.
[2] Wright, P.C., Stevenson, C., McEvoy, E, and Burgess, J.G. (1999) Opportunities for marine bioprocess intensification using novel bioreactor design: frequency of barotolerance in microorganisms obtained from surface waters. J. Biotechnol. 70, 343 -349.
*corresponding author: j.g.burgess@hw.ac.uk
