Metabolism of cinnamic acids by some Clostridiales and emendation of the descriptions of Clostridium aerotolerans, Clostridium celerecrescens and Clostridium xylanolyticum

The ability of Clostridium aerotolerans DSM 5434(T), Clostridium celerecres cens DSM 5628(T), Clostridium methoxybenzovorans DSM 12182(T), Clostridium stercorarium ATCC 35414(T), Clostridium subterminale DSM 2636, Clostridium termitidis DSM 5398(T), Clostridium thermolacticum DSM 2910(T), Clostridium thermopalmarium DSM 5974(T) and Clostridium xylanolyticum DSM 6555(T) to m etabolize cinnamic acid and various derivatives, with or without glucose su pplementation, was examined. Only C. aerotolerans DSM 5434T and C. xylanoly ticum DSM 6555T, closely related species, transformed cinnamic acid to 3-ph enylpropionic acid. Both species also reduced a wide range of cinnamic acid derivatives, including o-, m- and p-coumaric, o-, m- and p-methoxycinnamic , p-methylcinnamic, caffeic, ferulic, isoferulic and 3,4,5-trimethoxycinnam ic acids to their corresponding 3-phenylpropionic acid derivatives. C. aero tolerans DSM 5434T, however, also decarboxylated p-coumaric acid into 4-vin ylphenol, which was then reduced to 4-ethylphenol. C. celerecrescens was gr ouped with C. aerotolerans and C. xylanolyticum in subcluster XIVa of the C lostridiales. C. celerecrescens DSM 5628T only metabolized m- and p-methoxy cinnamic and p-methylcinnamic acids to their corresponding 3-phenylpropioni c acid derivatives, reducing the double bond in the C-3 aliphatic side chai r. Addition of glucose markedly increased the yield of the biotransformatio ns by these three species. An emendation of the descriptions of C. aerotole rans, C. celerecrescens and C. xylanolyticum is proposed, based on these ob servations.