Effects of pH and dissolved CO2 level on simultaneous production of 2,3-butanediol and succinic acid using Klebsiella pneumoniae

► A strategy for co-production of 2,3-butanediol and succinic acid was developed. ► Succinic acid productions were enhanced by increasing CO2 levels. ► 77.1 g l−1 2,3-butanediol and 28.7 g l−1 succinate were obtained at the same fermentation process.