The influences of pH control strategies on the distribution of 1,3-propanediols and 2,3-butanediols production by an isolated indigenous Klebsiella sp. Ana-WS5

In the simultaneous biological production of 1,3-propanediols (PDO) and 2,3-butanediols (BDO), glycerol was suggested to be a suitable carbon source. Extra addition of 10 g/L of lactic acid can create about a 30% increase in total diols production compared to the control batch. Several different pH control strategies were investigated. The results indicated that the batch with the uncontrolled pH had the highest total diols production among all pH control strategies, although it had the lowest productivity. Even the strategy of pH fluctuation did not enhance total diols production, it significantly enhanced the productivity. The soluble metabolite products (SMPs) analysis also indicated that the pH fluctuation will only affect BDO production, but had no impacts on the induction of more metabolites produced. Conclusively, both adding lactic acid and the pH fluctuation strategy are simple and efficient methods of simultaneously enhancing BDO and PDO production.