Enhanced L-lysine into 1,5-diaminopentane conversion via statistical optimization of whole-cell decarboxylation system

Abstract

The global lysine companies in the feed industry have steadily built their production facilities due to the high demand for L-lysine in animal farms, and in recent years there have been excessive supply problems and the world market price of L-lysine has fallen. In this study, the conversion of 1,5-diaminopentane (DAP) by decarboxylation of L-lysine was strategically chosen to enhance the value of lysine. The decarboxylation is enzymatically accessible, and Hafnia alvei, which is the producer of L-lysine decarboxylase, was applied as a whole-cell form. In the designed whole-cell biocatalytic system, the major four reaction factors were selected by fundamental investigation and then statistical optimizationwas performed to estimate the optimumcondition. The predicted conversionwas assessed at about 94.6% at the optimum conditions (125.1 mM L-lysine and 71.5 g/L acetone concentration at 35.2 °C for 8.4 h). Under the determined conditions, DAP conversions by using analytical, feed and industrial crude L-lysine were found to be 98.3%, 92.5% and 72.4%, respectively. These results could be suggested to solve the problem of excessive supplied lysine and also to provide guidance for improved enzymatic conversion by statistical optimization.