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Temperature resistant mutants of Rhodobacter capsulatus generated by a directed evolution approach and effects of temperature resistance on hydrogen production
- Source :
-
International Journal of Hydrogen Energy . Nov2012, Vol. 37 Issue 21, p16466-16472. 7p. - Publication Year :
- 2012
-
Abstract
- Abstract: Hydrogen (H2) is a promising alternative energy carrier which can be produced biologically. Rhodobacter capsulatus, a non-sulfur purple photosynthetic bacterium, can produce H2 under nitrogen-limited, photoheterotrophic conditions by using reduced carbon sources such as simple organic acids. Outdoor closed photobioreactors; used for biological H2 production are located under direct sunlight, as a result; bioreactors are exposed to temperature fluctuations during day time. In this study to overcome this problem, temperature-resistant mutants (up to 42°C) of R. capsulatus were generated in this study by a directed evolution approach. Eleven mutant strains of R. capsulatus DSM 1710 were obtained by initial ethyl methane sulfonate (EMS) mutagenesis of the wild-type strain, followed by batch selection at gradually increasing temperatures up to 42°C under respiratory conditions. The genetic stability of the mutants was tested and eight were genetically stable. Moreover, H2 production of mutant strains was analyzed; five mutants produced higher amounts of H2 when compared to the DSM 1710 wild-type strain and three mutants produced less H2 by volume. The highest H2- producing mutant (B41) produced 24% more H2 compared to wild type, and the mutant with lowest H2-production capacity (A52) generated 7% less H2 compared to the wild type. These results indicated that heat resistance of R. capsulatus can be improved by directed evolution, which is a useful tool to improve industrially important microbial properties. To understand molecular changes that confer high temperature-resistance and high hydrogen production capacity to these mutants, detailed transcriptomic and proteomic analyses would be necessary. [Copyright &y& Elsevier]
Details
- Language :
- English
- ISSN :
- 03603199
- Volume :
- 37
- Issue :
- 21
- Database :
- Academic Search Index
- Journal :
- International Journal of Hydrogen Energy
- Publication Type :
- Academic Journal
- Accession number :
- 82198804
- Full Text :
- https://doi.org/10.1016/j.ijhydene.2012.02.169