FERMENTATION MEDIUM OPTIMIZATION FOR 1,3-PROPANEDIOL PRODUCTION USING TAGUCHI AND BOX-BEHNKEN EXPERIMENTAL DESIGNS

Klebsiella species are excellent 1,3-propanediol (1,3 PDO) producers. Klebsiella pneumoniae is a well-studied microorganism and, therefore, its metabolic pathway is known. Accordingly, a number of by-products are simultaneously produced together with 1,3 PDO. Optimization of medium composition significantly decreased these by-products' concentrations. Optimization of culture media concentrations on 1,3 PDO production by K. pneumoniae was studied using statistical experimental designs and analysis, namely, Taguchi Orthogonal Array (TOA) and Box-Behnken design (BBD). The optimal composition of the fermentation medium for maximum 1,3 PDO yield, with a LIS (2 boolean AND 1 x 3 boolean AND 7) design using TOA, and after that, a three-level three-factor BBD, was obtained. The most significant chemicals were found to be glycerol (p<0.0001) and K2HPO4 (p<0.05). MgSO4 center dot 7H(2)0, which is the third significant factor obtained from TOA, was not found to be significant (p>0.05) from BBD. A maximum 1,3 PDO concentration of 23.6 g/L was obtained which is higher compared to that foreseen by the statistical model (9.3 g/L).