Methane utilization by Methylobacterium species: new evidence but still no proof for an old controversy

Recently, Van Aken et al. (2004) reported on the isolation of a novel species of the genus Methylobacterium, Methylobacterium populi, from internal tissues of poplar trees and claimed that representatives of this species can use methane as the sole source of carbon and energy. The methanotrophic potential of representatives of the genus Methylobacterium is the subject of an old and murky debate, and we think that any new evidence on this topic needs to be proven and verified to the strictest scientific standards.