Keiko MAKI

Attempts at Cultivation of Novel Methanogen by Using Anaerobic, Syntrophic Enrichment Cultures with Molecular Approaches

Akiyoshi OHASHI, Hideki HARADA


Accumulation of information of 16S rRNA gene and development of molecular approach were proved that organisms isolated yet exist in environment and methanogen done with an object by this study is the one. Methanogen is known as microorganisms taking the last stage of organic matter resolution in anaerobic condition and 26 genus 96 species are isolated. However isolation report of novel methanogen is extremely few recently.

As the one reason, when hydrogenotrophic methanogen is cultures generally, what extremely high hydrogen share of 200kPa that canft be nature environment is overwhelmed, and is cultured is made. When it was cultured with a condition different from such real environment at all, hydrogenotrophic methanogen that is hard to take in hydrogen comparatively is superior, and there is possibility to growth. Accordingly, if imitation is done of real environment, and hydrogen of low partial pressure can be supplied in uniformity, it is thought when culture of novel hydrogenotrophic methanogen becomes possible. So I paid attention to anaerobic syntrophic culture as the line that could supply the hydrogen that overwhelmed a low partial pressure in uniformity slowly, and isolation of novel hydrogenotrophic methanogen was tried.

The enrichment culture cultivated by high hydrogen partial pressure contained clones closed to 16S rDNA of Archaea isolated already. But the dominancy clone in enrichment culture cultivated by low hydrogen partial pressure was contained to clone cluster or new family.

These results suggest a possibility of isolating of novel methanogen using anaerobic syntrophic cultures.