Methods for producing isobutene from 3-methylcrotonic acid

A method for the production of isobutene comprising

• (a) enzymatically converting 3-methylcrotonyl-CoA into 3-methylcrotonic acid,
• wherein the conversion of 3-methylcrotonyl-CoA into 3-methylcrotonic acid is carried out by:
• i. a single enzymatic reaction in which 3-methylcrotonyl-CoA is directly converted into 3-methylcrotonic acid by a CoA transferase (EC 2.8.3.-);
• ii. a single enzymatic reaction in which 3-methylcrotonyl-CoA is directly converted into 3-methylcrotonic acid by a thioester hydrolase (EC 3.1.2.-);
• or
• iii. two enzymatic steps comprising
• a. first enzymatically converting 3-methylcrotonyl-CoA into 3-methylcrotonyl phosphate by a phosphate butyryltransferase (EC 2.3.1.19) or a phosphate acetyltransferase (EC 2.3.1.8);
• and
• b. then enzymatically converting the thus obtained 3-methylcrotonyl phosphate into said 3-methylcrotonic acid by a phosphotransferase with a carboxy group as acceptor (EC 2.7.2.-), and
• (b) enzymatically converting the 3-methylcrotonic acid produced in (a) into isobutene, wherein the conversion of 3-methylcrotonic acid into isobutene is carried out by a 3-methylcrotonic acid decarboxylase selected from:
• i. an FMN-dependent decarboxylase associated with an FMN prenyl transferase (EC 2.5.1.-);
• or
• ii. an aconitate decarboxylase (EC 4.1.1.6);
• or
• iii. a methylcrotonyl-CoA carboxylase (EC 6.4.1.4);
• or
• iv. a geranoyl-CoA carboxylase (EC 6.4.1.5);
• or
• v. a protocatechuate (PCA) decarboxylase (EC 4.1.1.63).