Reactions of the three alternative pathways for formaldehyde oxidation in B. fungorum LB400. FlhA, GSH, NAD-linked FDH; FghA, FGH; FdhA, NAD-linked (GSH-independent) FDH; Fae, formaldehyde-activating enzyme; MtdB, NAD(P)-linked methylene-H4MPT dehydrogenase; Mch, methenyl-H4MPT cyclohydrolase; Fhc, formyltransferase-hydrolase complex. Genes subjected to mutation in this study are denoted by asterisks.