Microarray analysis of the effects of heat and cold stress on hydrogen production metabolism of Rhodobacter capsulatus

Gürgan Doğan, Muazzez
Rhodobacter capsulatus DSM1710 is a purple non-sulfur bacterium capable of hydrogen production via photofermentation. Biohydrogen is a clean and renewable way of hydrogen production, which can be achieved by PNS bacteria in outdoor large scale photobioreactors using sun light. In outdoor conditions bacteria can be exposed to heat and cold stress. In this study in order to understand the effects of heat and cold stress on photofermentative hydrogen production and gene expression profile of R.capsulatus on acetate as the carbon source, microarray analysis was carried out. Since there is no commercially available microarray chip for R.capsulatus, an Affymetrix GeneChip® was designed and it was manufactured by Affymetrix.The experiments were conducted at 30 ⁰C as the control condition, 42 ⁰C for heat stress and 4 ⁰C for cold stress under constant illumination of 2000 lux. Growth of bacteria, pH of the media, hydrogen production and acetate consumption weredetermined periodically. Upon heat and cold stress hydrogen production was stopped, while bacterial growth continued under cold stress but stopped under heat stress. Acetate could be utilized totally under cold stress, however, some acetate remained in the medium after heat stress application. Microarray analysis revealed that genes taking role in nitrogen metabolism, photosynthesis and electron transport, which are core metabolisms for hydrogen production were highly up regulated under cold stress, while down regulated under heat stress, meaning that heat stress inhibited hydrogen and energy production of R.capsulatus. Moreover, cell envelope and related transporter and binding proteins were negatively affected by heat stress.


Microarray analysis of high light intensity stress on hydrogen production metabolism of Rhodobacter capsulatus
Gurgan, Muazzez; Koku, Harun; EROĞLU, İNCİ; Yucel, Meral (Elsevier BV, 2020-01-29)
Biohydrogen obtained from purple non sulfur bacteria (PNSB) is an environmentally friendly alternative for hydrogen production. PNSB can be employed in large scale outdoor photobioreactors to produce hydrogen by photofermentation with sunlight as the light source. In external environmental conditions, however, bacteria can experience stress due to high light intensities, which can inhibit or slow down hydrogen production. Previous studies with other PNSB showed varying responses to light intensities (above ...
Microarray analysis of the effects of light intensity on hydrogen production metabolism of rhodobacter capsulatus
Gürgan Eser, Muazzez; Yücel, Ayşe Meral; Koku, Harun; Department of Biology (2017)
Biohydrogen generated by purple non-sulfur bacteria is a clean and renewable method of hydrogen production. It can be achieved in outdoor phototobioreactors using the natural sun light in lab to pilot scales. Light is one of the most important parameter affecting hydrogen production in the outdoor condition. Hydrogen productivity may decrease upon light intensity stress by sun light and the diurnal cycle in outdoor conditions. It is important to understand the metabolic response of these bacteria to varying...
Deletion mutation of GLNB and GLNK genes in rhodobacter capsulatus to enhance biohydrogen production
Pekgöz, Gülşah; Gündüz, Ufuk; Eroğlu, İnci; Department of Biotechnology (2010)
Rhodobacter capsulatus is a photosynthetic, purple non-sulfur (PNS) bacterium that produces biohydrogen via photofermentation. Nitrogenase enzyme is responsible for hydrogen production; during fixation of molecular nitrogen into ammonium, hydrogen is produced. Since this process is an energetically expensive process for the cell, hydrogen production is strictly controlled at different levels. When ammonium is present in the environment, hydrogen production completely ceases. The key proteins in the regulati...
Transcriptional analysis of hydrogenase genes in rhodobacter sphaeroides O.U.001
Doğrusöz, Nihal; Gündüz, Ufuk; Department of Biology (2004)
In photosynthetic non-sulphur bacteria, hydrogen production is catalyzed by nitrogenases and hydrogenases. Hydrogenases are metalloenzymes that are basically classified into: the Fe hydrogenases, the Ni-Fe hydrogenases and metal-free hydrogenases. Two distinct Ni-Fe hydrogenases are described as uptake hydrogenases and bidirectional hydrogenases. The uptake hydrogenases are membrane bound dimeric enzymes consisting of small (hupS) and large (hupL) subunits, and are involved in uptake and the recycling of hy...
Evaluation of hydrogen production by Rhodobacter sphaeroides OU001 and its hupSL deficient mutant using acetate and malate as carbon sources
KARS, GÖKHAN; Gündüz, Ufuk; Yucel, Meral; Rakhely, Gabor; Kovacs, Kornel L.; Eroglu, Inci (2009-03-01)
Rhodobacter sphaeroides O.U.001 is one of the candidates for photobiological hydrogen production among purple non-sulfur bacteria. Hydrogen is produced by Mo-nitrogenase from organic acids such as malate or lactate. A hupSL in frame deletion mutant strain was constructed without using any antibiotic resistance gene. The hydrogen production potential of the R. sphaeroides O.U.001 and its newly constructed hupSL deleted mutant strain in acetate media was evaluated and compared with malate containing media. Th...
Citation Formats
M. Gürgan Doğan, “Microarray analysis of the effects of heat and cold stress on hydrogen production metabolism of Rhodobacter capsulatus,” M.S. - Master of Science, Middle East Technical University, 2011.