Potential evaluation of valuable products for methane oxidizing bacteria

Methane is second abundant global warming gas and is receiving a lot of attention to reduce. Methane oxidizing bacteria is known not only to assimilate methane, but also have a possibility to produce valuable products such as polyhydroxy alcanoate (PHA), one of valuable products and used as biodegradable and bio compatible resin. In my research, methane oxidizing bacteria (MOB) were accumulated from paddy soil that methane is sputtering from underground, and checked the potential of PHA. MOB were accumulated by semi-batch culture and Methylosinus sp. was dominated. 1403 mg-CH4/g-CDW/Day of methane oxidizing rate as maximum value was obtained. Also, the change of consortium during semi-batch culture was obtained by using 16S rRNA gene amplicon sequence, and dynamics of changing domination from Type1 MOB to Type2 was observed. qPCR analysis revealed that functional gene pmoA coding methane mono oxygenase increased as phaA coding PHA synthase increased, which suggests that MOB may have a possibility to produce PHA.