Production of acetolactate byStreptococcus diacetylactisandLeuconostocspp.

Summary The effect of several parameters on the decarboxylation of α-acetolactic acid (ALA) to diacetyl and acetoin was studied in model experiments. At temperatures > 50 °C, relatively more diacety1 than acetoin was produced. Regardless of temperature, HC1 increased the production of acetoin (58 mol% conversion at max.) and prevented the production of diacetyl. Steam distillation of ALA caused ~ 55 mol%/h conversion to acetoin and 7 mol%/h to diacetyl. Production of acetoin was proportional to the ALA concentration. Based on these results two methods for the quantitative measurement of ALA were developed. Only one of 17 strains ofStreptococcus diacetylactis (Lactococcus lactissubsp.lactisbiovar.diacetilactis, new nomenclature) and three of three strains ofLeuconostocspp. produced ALA. The implications of these findings are discussed.