Four-carbon dicarboxylic acids are widely used in food,pharmaceutical and chemical industries.Thus there is a huge market potential for then.S.cerevisiae is regarded as the best candidate microorganism for producing four-carbon dicarboxylic acids.Unfortunately,there is strong tendency for ethanol formation under fully aerobic conditions when sugar is present in access in batch culture,which leads to the loss of carbon flow.To reduce ethanol formation,the positive regulate gene THI2 in thiamine synthetic pathway was deleted,and the ethanol titer decreased from 5.27 ± 0.23 g /L to 0.53 ± 0.12 g /L.However,this strategy led to a week growth and glucose consumption.Then cell growth and glucose consumption were improved but still weak when 0.04 μmol /L ThDP was added.To further improve cell growth and glucose consumption,the effect of NAD+on FMME-002△THI2 was explored.Results show that glucose consumption and cell growth were improved by 48.6% and 47.2%,respectively,while ethanol titer only increased 0.56 g /L when 1 000 μg /L NAD+was added.In brief,ethanol formation was reduced efficiently by regulating the level of cofactors thiamine and NAD+,which provideed a novel strategy to solve this universal problem in the field of production of four-carbon dicarboxylic acids from S.cerevisiae.