On the specifity and stereospecificity of the conversion of different 2,3-unsaturated acids by Clostridium kluyveri (author's transl)]

Further 2,3-unsaturated acids are revealed which can be reduced by Clostridium kluyveri with crotonate or butyrate as hydrogen donors. Unsaturated and saturated 3-halogenated acids are transformed into the saturated halogen-free acids. The following reaction sequence is proposed: a) hydrogenation, b) elumination of HX and c) again hydrogenation. Tiglinate ((E)-2-methyl-2-butenoate) and (E)-2-methyl-2-pentenoate are stereospecifically reduced to the (S)-2-methyl substituted acids. C. kluyveri contains endogenous material; in the presence of hydrogen acceptors such as 2,3-unsaturated acids this is degraded to acetate, and the reducing equivalents liberated hydrogenate the unsaturated acid. In a transient phase the hydration products of the unsaturated acids are present in the non-activated form in appreciable amounts. Tiglinate as well as crotonate is partially converted to ethyl methyl ketone and aceton and/or propanol, respectively.