title: Conversion of levulinic acid to 2-butanone by acetoacetate decarboxylase from Clostridium acetobutylicum.
abstract: In this study, a novel system for synthesis of 2-butanone from levulinic acid (γ-keto-acid) via an enzymatic reaction was developed. Acetoacetate decarboxylase (AADC; E.C. 4.1.1.4) from Clostridium acetobutylicum was selected as a biocatalyst for decarboxylation of levulinic acid. The purified recombinant AADC from Escherichia coli successfully converted levulinic acid to 2-butanone with a conversion yield of 8.4-90.3 % depending on the amount of AADC under optimum conditions (30 °C and pH 5.0) despite that acetoacetate, a β-keto-acid, is a natural substrate of AADC. In order to improve the catalytic efficiency, an AADC-mediator system was tested using methyl viologen, methylene blue, azure B, zinc ion, and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) as mediators. Among them, methyl viologen showed the best performance, increasing the conversion yield up to 6.7-fold in comparison to that without methyl viologen. The results in this study are significant in the development of a renewable method for the synthesis of 2-butanone from biomass-derived chemical, levulinic acid, through enzymatic decarboxylation.
authors.affiliation: Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul 136-791, South Korea.
authors.forename: Kyoungseon
authors.initials: K
authors.lastname: Min
authors.forename: Seil
authors.initials: S
authors.lastname: Kim
authors.forename: Taewoo
authors.initials: T
authors.lastname: Yum
authors.forename: Yunje
authors.initials: Y
authors.lastname: Kim
authors.forename: Byoung-In
authors.initials: BI
authors.lastname: Sang
authors.forename: Youngsoon
authors.initials: Y
authors.lastname: Um
mesh_terms: D002074:Butanones / Q000378:metabolism*; D002262:Carboxy-Lyases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D046969:Clostridium acetobutylicum / Q000201:enzymology*; D020536:Enzyme Activators / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D007982:Levulinic Acids / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013696:Temperature
chemical_list: D002074:Butanones; D020536:Enzyme Activators; D007982:Levulinic Acids; D011994:Recombinant Proteins; C005222:methylethyl ketone; D002262:Carboxy-Lyases; C023743:acetoacetate decarboxylase; C032246:levulinic acid