- 著者
-
高橋 令二
徳山 龍明
- 出版者
- Japanese Society of Microbial Ecology / The Japanese Society of Soil Microbiology
- 雑誌
- Bulletin of Japanese Society of Microbial Ecology(日本微生物生態学会報) (ISSN:09117830)
- 巻号頁・発行日
- vol.9, no.3, pp.135-147, 1994-12-31 (Released:2009-10-05)
- 参考文献数
- 62
CO2 accumulation as a factor of global warming is requiring attention. Obligate chemoautotrophic bacteria grow independently of organic conditions with energy from the oxidation of reduced inorganic compounds and CO2 from the atmosphere as sole carbon sources. Chemoautotrophic bacteria consume (fix) CO2, and assimilate CO2 via the reductive pentose phosphate cycle (Calvin cycle). CO2 assimilation via the reductive tricarboxylic acid cycle (TCA cycle) occurs particularly in thermophilic hydrogen-oxidizing bacteria. This paper reviews studies on the tricarboxylic acid cycle in relation to CO2 fixation reactions of chemoautotrophic bacteria, especially nitrifying bacteria.Nitrifying bacteria promote nitrification, a stage in the nitrogen cycle. Ammonia-oxidizing bacteria (Nitrosomonas) oxidize ammonia as the sole nitrogen source of nitrite, and nitrite-oxidizing bacteria (Nitrobacter) oxidize nitrite as the sole nitrogen source of nitrate. Both bacteria fix CO2 mainly via the Calvin cycle in which ribulose 1, 5-bisphosphate carboxylase/oxygenase (RuBisCO) is a key enzyme. Less CO2 is assimilated by the phosphoenolpyruvate carboxylase pathway. The TCA cycle of nitrifying bacteria was studied and CO2 assimilation was clarified in greater detail.