Methanogen

About: Methanogen is a research topic. Over the lifetime, 1146 publications have been published within this topic receiving 48254 citations.

Engineering nonphotosynthetic carbon fixation for production of bioplastics by methanogenic archaea

Abstract: The conversion of CO2 to value-added products allows both capture and recycling of greenhouse gas emissions. While plants and other photosynthetic organisms play a key role in closing the global carbon cycle, their dependence on light to drive carbon fixation can be limiting for industrial chemical synthesis. Methanogenic archaea provide an alternative platform as an autotrophic microbial species capable of non-photosynthetic CO2 fixation, providing a potential route to engineered microbial fermentation to synthesize chemicals from CO2 without the need for light irradiation. One major challenge in this goal is to connect upstream carbon-fixation pathways with downstream biosynthetic pathways, given the distinct differences in metabolism between archaea and typical heterotrophs. We engineered the model methanogen, Methanococcus maripaludis, to divert acetyl-coenzyme A toward biosynthesis of value-added chemicals, including the bioplastic polyhydroxybutyrate (PHB). A number of studies implicated limitations in the redox pool, with NAD(P)(H) pools in M. maripaludis measured to be <15% of that of Escherichia coli, likely since methanogenic archaea utilize F420 and ferredoxins instead. Multiple engineering strategies were used to precisely target and increase the cofactor pool, including heterologous expression of a synthetic nicotinamide salvage pathway as well as an NAD+-dependent formate dehydrogenase from Candida boidinii. Engineered strains of M. maripaludis with improved NADH pools produced up to 171 ± 4 mg/L PHB and 24.0 ± 1.9% of dry cell weight. The metabolic engineering strategies presented in this study broaden the utility of M. maripaludis for sustainable chemical synthesis using CO2 and may be transferable to related archaeal species.

Method for improving methane yield by organic waste water anaerobic fermentation

Abstract: The invention relates to a method used for raising the output of marsh gas by using anaerobic fermentation of organic effluent water, which pertains to the technical field of biological treatment of effluent water. The invention adopts simulated organic effluent water or practical wastewater from chemical industry as treatment objects, by adding trace metal element Co and metal ion chelating agent to an anaerobic reactor to improve the biological availability of trace metal elements which are essential for methanogen and promote the growth and activity of methanogen, thereby, methane output and transformation efficiency of contaminating material of the system is improved. The method needs only extreme micro-amount of trace metal element Co and metal ion chelating agent, therefore, the invention is not only convenient to be manipulated with high efficiency and but also low in cost which leads the invention to be extensively applicable in engineering practice.

Biotechnological potential of methanogens.

Abstract: Methane produced microbiologically is currently used as an energy source, especially by cities and industries, albeit at a level far below its potential; the incentive is currently to save money on disposal costs for waste problems. Anaerobic digestion can be helpful in degrading several halogenated hydrocarbon wastes, and methanogens are partly responsible. Ethane instead of methane may be a future product of interest. Some pure cultures of methanogens may be suitable for production of B-12, or perhaps the speciality biochemical F420, a 5-deazaflavin of interest to both methanogen and streptomyces researchers. Methanogens can cause a variety of problems, including biocorrosion, increased atmospheric methane, and ruminant nutrition loss. Studies of tropical wetlands, including rice paddies and swamps, and the study of a variety of ruminants in the tropics are particularly interesting and appropriate at this time, with respect to methane produced in these ecosystems. In some cases, it may be possible to control methane production by the use of inhibitors or ecological control mechanisms.