Cadaverine Production by Using Cross-Linked Enzyme Aggregate of Escherichia coli Lysine Decarboxylase

Lysine decarboxylase (CadA) converts _L-lysine into cadaverine (1,5-pentanediamine), which is an important platform chemical with many industrial applications. Although there have been many efforts to produce cadaverine through the soluble CadA enzyme or Escherichia coli whole cells overexpressing the CadA enzyme, there have been few reports concerning the immobilization of the CadA enzyme. Here, we have prepared a cross-linked enzyme aggregate (CLEA) of E. coli CadA and performed bioconversion using CadA^CLEA. CadA^free and CadA^CLEA were characterized for their enzymatic properties. The optimum temperatures of CadA^free and CadA^CLEA were 60°C and 55°C, respectively. The thermostability of CadA^CLEA was significantly higher than that of CadA^free. The optimum pH of both enzymes was 6.0. CadA^free could not be recovered after use, whereas CadA^CLEA was rapidly recovered and the residual activity was 53% after the 10^th recycle. These results demonstrate that CadA^CLEA can be used as a potential catalyst for efficient production of cadaverine.