Effect of different conditions on citrate metabolism by Oenococcus oeni in model wine

With Oenococcus oeni 31- DH as material for malolactic fermentation,the effects of p H,ethanol and glucose on the citrate metabolism during and after malolactic fermentation were studied.Ion exclusion chromatography was used to measure the contents of the related substances. The results showed that the experiment was time- saving with simple pretreatments,good separation degree,recovery rate between 87% ~ 108% and RSD between 0.77% ~ 4.33% which met the requirements of analysis.With lower p H values,higher ethanol contents and lower glucose contents of the fermentation broth,the citrate metabolism was slower,the lactic acid,acetic acid and 2,3- butanediol contents were lower,while the diacetyl content peak was higher.When the fermentation broth contained no ethanol,the malic acid,citric acid and glucose were metabolized rapidly,associated with mass growth of bacteria,higher contents of lactic acid,acetic acid and 2,3- butanediol,while no diacetyl.When the fermentation broth contained no glucose,the rate of citrate metabolism accelerated,lactic acid production was low and the production of 2,3- butanediol and diacetyl was high.p H,ethanol and glucose had significant effects on the citrate metabolism of O.oeni.