The aim of this work was to isolate methanotrophs (methane oxidizing bacteria) that can directly convert
biogas produced at a commercial anaerobic digestion (AD) facility to methanol. A methanotrophic
bacterium was isolated from solid-state anaerobic digestate. The isolate had characteristics comparable
to obligate methanotrophs from the genus Methylocaldum. This newly isolated methanotroph grew on
biogas or purified CH4 and successfully converted biogas from AD to methanol. Methanol production
was achieved using several methanol dehydrogenase (MDH) inhibitors and formate as an electron donor.
The isolate also produced methanol using phosphate with no electron donor or using formate with no
MDH inhibitor. The maximum methanol concentration (0.43 ± 0.00 g L1) and 48-h CH4 to methanol
conversion (25.5 ± 1.1%) were achieved using biogas as substrate and a growth medium containing
50 mM phosphate and 80 mM formate.