Evaluation of anaerobic ethane oxidation capability of the denitrifying anaerobic methane oxidation culture

Anaerobic oxidation of ethane, propane, and butane by archaea is discovered recently while denitrifying anaerobic methane oxidation (DAMO) has been studied intensively over 15 years. Therefore, the anaerobic ethane oxidation capability of DAMO culture was preliminarily evaluated in this study. The batch experiment showed ethane consumption coupling with nitrate reduction. Community analysis showed highly enriched Parvibaculum, uncultured Rhodocyclaceae, and Aquabacterium, indicating their important roles in the cultures. But the dramatic decrease of DAMO archaea in ethane-supplying system illustrated that it did not have the ability to oxidize ethane anaerobically, thus the original methyl-coenzyme M reductase without evolution or adaptation in DAMO archaea was not versatile in ethane oxidation. This is the first experimental evaluation of DAMO archaea, and even the anaerobic methanotrophic (ANME) archaea in oxidation of non-methane gaseous alkanes. The results may provide new information to understand the function and involvement of ANME archaea in natural alkane oxidation processes and global carbon cycles. © 2020 Elsevier Ltd