There was no substantiated
evidence of a methanotroph capable of growing on substrates containing
C C bonds . Fairly recently, Methylocella,
a facultative genus of methanotroph have been discovered to be
capable of utilizing certain multi-C compounds, such as acetate and
ethanol, as energy sources in addition to CH4. These methanotrophs
have distinctly altered the perception of this group of bacteria
. Not only did this disprove the existent idea of
the obligate nature of all methanotrophs, but also assessments of
methanotrophic activity could have overlooked the apparent longterm
stimulatory effect that multi-C substrates could have on CH4
oxidation in bacteria such as Methylocella silvestris BL2 . However, knowledge about
the Methylocella is still limited. An understanding of the molecular
physiology of Methylocella spp. may provide insights into the factors
that restrict utilization of multi-C compounds in other methanotrophs
and autotrophic microorganisms .