A CYCLIC PATHWAY FOR THE BACTERIAL DISSIMILATION OF 2,3-BUTANEDIOL, ACETYLMETHYLCARBINOL, AND DIACETYL I

Abstract

Bacteria able to grow with 2, 3 butanediol or acetylmethylcarbinol as the sole source of C develop a cyclic mechanism for the conversion of these compounds to acetate. Diacetyl is an intermediate in the process and is converted to diacetylmethylcarbinol ((CH3CO)2(CH3)COH) and acetate by a diphosphothiamin-catalyzed acyloin condensation reaction. Diacetylmethylcarbinol is reduced to acetylbutanediol (CH3 CHOHCOH(COCH3)CH3) which, in turn, is hydrolyzed to 2,3-butanediol and acetate. All the reactions in the cycle can take place anaerobically. Evidence is presented to show that this cyclic process operates during normal aerobic growth on the 4-C compounds. Methods for determination of diacetylmethylcarbinol and acetylbutanediol, compounds which react as acetylmethylcarbinol in the Voges-Proskauer test, are described.