In Vitro High-Pressure Incubation and Activity Measurement of Deep-Sea Methanogenic Archaea
A high-pressure cultivation or incubation system can reproduce elevated in situ pressure conditions of deep-sea environments in a laboratory. It has significantly contributed to the piezophysiological studies of microorganisms, especially psychrophilic heterotrophs, since the first report of high-pressure incubation of deep-sea microorganisms many decades ago. The deep-sea microorganisms growing on gaseous substrates such as H2, CH4, N2, and CO2 play important roles in biogeochemical cycles around gas-rich deep-sea environments such as deep-sea hydrothermal vent habitats. However, due to the difficulties in obtaining pressure-proof gastight high-pressure cultivation systems for increased gaseous substrates and the tricky way of their operations, only a few gas-utilizing microorganisms have been investigated under high-pressure conditions so far. Here, we describe the protocols for high-pressure microbiological experiments with easy handling systems that enable the high-pressure cultivation of hyperthermophilic hydrogenotrophic methanogens and the following highly sensitive measurement of methanogenesis activity in the deep-sea sediments using radiolabeled tracers under high-pressure conditions.
Keywords:Activity measurement High-pressure incubation Methanogenesis
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