Aim: To improve phenylalanine ammonia lyase (E.C.4.3.1.5-PAL) activity in recombinant Escherichia coli. Some methods for enrichment of PAL activity in recombinant E. coli JM109 were described. In an effort to create a rich enzyme source these methods would lead to improvements in the production of L-phenylalanine.
Methods and results: The possibilities of enriching PAL activity in recombinant E. coli was investigated by using individual and combinations of amino acids, organic solvents and surfactants. PAL activity was induced by adding combination of L-phenylalanine and L-tyrosine, activities as high as 64.3 U g(-1)of cells were obtained and enzyme activity was enriched by over 3.5-fold in comparison with the control. Permeabilization with cetyl trimethyl ammonium bromide or the acetone significantly enriched cellular PAL activity, which improved over 8.2- and 9.0-fold compared with the control, as high as 148.5 and 164.5 U g(-1)of cells respectively.
Conclusion: These efforts may provide some effective methods for enhancing L-phenylalanine ammonia lyase activity.
Significance and impact of the study: These approaches for manipulating recombinant E. coli in an effort to create a rich enzyme source would serve as a biotechnologically important protocol for production of L-phenylalanine.