In vitro methods for processing lignin and other aromatic compounds

A method of processing lignin, comprising contacting lignin comprising β-O-4 ether linkages in vitro with:

• a dehydrogenase comprising at least one of LigD, LigO, LigN, and LigL;
• a β-etherase comprising at least one of LigE, LigF, LigP, and an enzyme comprising a first polypeptide having an amino acid sequence of SEQ ID NO:40 or an amino acid sequence at least about 95% identical thereto and a second polypeptide having an amino acid sequence of SEQ ID NO:42 or an amino acid sequence at least about 95% identical thereto;
• and
• a non-stereospecific glutathione lyase comprising an amino acid sequence at least about 80% identical to any of:
• SEQ ID NO:18 (NaGSTNu);
• residues 21-313 of SEQ ID NO:20 (recombinant NaGSTNu);
• SEQ ID NO:22 (SYK6GSTNu);
• residues 21-324 of SEQ ID NO:24 (recombinant SYK6GSTNu);
• SEQ ID NO:26 (ecYghU);
• residues 21-313 of SEQ ID NO:28 (recombinant ecYghU);
• and
• SEQ ID NO:32 (ssYghU),
• wherein the non-stereospecific glutathione lyase comprises at least four of:
• threonine or a conservative variant of threonine at a position corresponding to position 51 of SEQ ID NO:18 (NaGSTNu);
• asparagine or a conservative variant of asparagine at a position corresponding to position 53 of SEQ ID NO:18 (NaGSTNu);
• glutamine or a conservative variant of glutamine at a position corresponding to position 86 of SEQ ID NO:18 (NaGSTNu);
• lysine, a conservative variant of lysine, arginine, or a conservative variant of arginine at a position corresponding to position 99 of SEQ ID NO:18 (NaGSTNu);
• isoleucine or a conservative variant of isoleucine at a position corresponding to position 100 of SEQ ID NO:18 (NaGSTNu);
• glutamate or a conservative variant of glutamate at a position corresponding to position 116 of SEQ ID NO:18 (NaGSTNu);
• serine, threonine, a conservative variant of serine, or a conservative variant of threonine at a position corresponding to position 117 of SEQ ID NO:18 (NaGSTNu);
• and
• arginine or a conservative variant of arginine at a position corresponding to position 177 of SEQ ID NO:18 (NaGSTNu).