Biological production of multi-carbon compounds from methane

A method for producing isobutanol from a methane substrate comprising the steps of:

• (a) providing a methanotrophic host microorganism that metabolizes methane (CH4) to methanol (CH3OH) and methanol to formaldehyde (H2C═O);
• (b) introducing into the methanotroph host and expressing at least one exogenous polynucleotide open reading frame (ORF) under the control of suitable regulatory-sequences, wherein the at least one polynucleotide ORF encodes a polypeptide that catalyzes a reaction in an isobutanol pathway,
• wherein the at least one polynucleotide ORF is selected from the group consisting of acetolactate synthase (ALS), ketol-acid reductoisomerase (KARI), dihydroxy-acid dehydratase (DHAD), ketoacid decarboxylase (KDC) and alcohol dehydrogenase (ADH), and wherein the ALS polypeptide comprises an amino acid sequence having at least 90% sequence homology to SEQ ID NO:2, the KARI polypeptide comprises an amino acid sequence having at least 90% sequence homology to SEQ ID NO:4, the DHAD polypeptide comprises an amino acid sequence having at least 90% sequence homology to SEQ ID NO:6, the KDC polypeptide comprises an amino acid sequence having at least 90% sequence homology to SEQ ID NO:8 and the ADH polypeptide comprises an amino acid sequence having at least 90% sequence homology to SEQ ID NO:10;
• (c) feeding the methanotroph host produced according to step (b) a methane substrate under suitable growth conditions, wherein the host metabolizes methane to formaldehyde as set forth in step (a), wherein the formaldehyde is converted to pyruvate by means of an endogenous type I RuMP pathway or a type II serine pathway and the host metabolizes pyruvate to produce isobutanol;
• and
• (d) recovering the isobutanol produced.