Scientists discover new anaerobic bacteria that feed on natural gas
A German-American research team of biologists and geochemists has discovered hitherto unknown anaerobic bacteria in marine sediments which need only propane or butane for growth, as reported by the scientific journal Nature in its current online issue.
The hydrocarbons ethane, propane and butane - as well as the main component, methane - are the major constituents of natural gas. Biological processes may lead to the degradation of these hydrocarbons in underground petroleum reservoirs and other geological habitats.
energy :: sustainability :: biomass :: petroleum :: natural gas :: methane :: propane :: butane :: anaerobic oxidation :: bacteria ::
The researchers report the enrichment of sulphate-reducing bacteria (SRB) with the capacity to utilizate short-chain hydrocarbons in an anaerobic environment. The organisms are found in marine hydrocarbon seep areas.
Propane or n-butane as the sole growth substrate led to sediment-free sulphate-reducing enrichment cultures growing at 12, 28 or 60 °C. With ethane, a slower enrichment with residual sediment was obtained at 12 °C.
Isolation experiments resulted in a mesophilic pure culture (strain BuS5) that used only propane and n-butane (methane, isobutane, alcohols or carboxylic acids did not support growth). Complete hydrocarbon oxidation to CO2 and the preferential oxidation of 12C-enriched alkanes were observed with strain BuS5 and other cultures.
Metabolites of propane included iso- and n-propylsuccinate, indicating a subterminal as well as an unprecedented terminal alkane activation with involvement of fumarate.
According to RNA analyses, strain BuS5 affiliates with Desulfosarcina/Desulfococcus, a cluster of widespread marine SRB. An enrichment culture with propane growing at 60 °C was dominated by Desulfotomaculum-like SRB. Our results suggest that diverse SRB are able to thrive in seep areas and gas reservoirs on propane and butane, thus altering the gas composition and contributing to sulphide production.
References:
Olaf Kniemeyer, et. al. "Anaerobic oxidation of short-chain hydrocarbons by marine sulphate-reducing bacteria", Nature advance online publication 19 September 2007, doi:10.1038/nature06200
Eurekalert: Natural gas inhabited by unusual specialists - September 21, 2007.
The hydrocarbons ethane, propane and butane - as well as the main component, methane - are the major constituents of natural gas. Biological processes may lead to the degradation of these hydrocarbons in underground petroleum reservoirs and other geological habitats.
The bacteria isolated here for the first time from marine sediments use sulphate instead of oxygen for respiration and utilize propane and butane as their sole source of carbon and energy. These organisms are tough specialists that have become adapted to strictly utilising only these and no other substrates. - Heinz Wilkes, biogeochemist at GeoForschungsZentrum PotsdamThe investigations showed that the bacteria employ an unprecedented biochemical mechanism for transforming what are essentially unreactive hydrocarbons into reactive metabolites which may then be further oxidised to carbon dioxide. The findings concerning this reaction mechanism are an important step in designing new synthetic methods for selectively producing chemicals from hydrocarbons:
energy :: sustainability :: biomass :: petroleum :: natural gas :: methane :: propane :: butane :: anaerobic oxidation :: bacteria ::
The researchers report the enrichment of sulphate-reducing bacteria (SRB) with the capacity to utilizate short-chain hydrocarbons in an anaerobic environment. The organisms are found in marine hydrocarbon seep areas.
Propane or n-butane as the sole growth substrate led to sediment-free sulphate-reducing enrichment cultures growing at 12, 28 or 60 °C. With ethane, a slower enrichment with residual sediment was obtained at 12 °C.
Isolation experiments resulted in a mesophilic pure culture (strain BuS5) that used only propane and n-butane (methane, isobutane, alcohols or carboxylic acids did not support growth). Complete hydrocarbon oxidation to CO2 and the preferential oxidation of 12C-enriched alkanes were observed with strain BuS5 and other cultures.
Metabolites of propane included iso- and n-propylsuccinate, indicating a subterminal as well as an unprecedented terminal alkane activation with involvement of fumarate.
According to RNA analyses, strain BuS5 affiliates with Desulfosarcina/Desulfococcus, a cluster of widespread marine SRB. An enrichment culture with propane growing at 60 °C was dominated by Desulfotomaculum-like SRB. Our results suggest that diverse SRB are able to thrive in seep areas and gas reservoirs on propane and butane, thus altering the gas composition and contributing to sulphide production.
References:
Olaf Kniemeyer, et. al. "Anaerobic oxidation of short-chain hydrocarbons by marine sulphate-reducing bacteria", Nature advance online publication 19 September 2007, doi:10.1038/nature06200
Eurekalert: Natural gas inhabited by unusual specialists - September 21, 2007.
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