Heterologous Expression of Tyrosine Ammonia Lyase from Rhodotorula glutinis in Escherichia coli

Abstract:

As one of the key enzyme in the phenylalanine metabolism pathway，tyrosine ammonia-lyase（TAL） catalyzes the formation of p-coumaric acid from L-tyrosine. p-Coumaric acid serves as a precursor of a wide array of anti-oxidative and anti-aging natural phenylpropanoid products，such as resveratrol and naringenin. In this study，the tal gene from Rhodotorula glutinis was selected，codon optimized and overexpressed in Escherichia coli BL21（DE3）. After treatment with ammonium sulfate precipitation，the recombinant TAL was purified with anion exchange chromatography and gel filtration chromatography，resulting in specific activity of 1.78 U/mg enzyme. Under the same culture conditions，different expression vectors were constructed to get different productions of p-coumaric acid. Among them，the strain with pET-32a（+） as expression vector gained the highest yield of p-coumaric acid，up to 196.3 mg/L after 24 h fermentation from L-tyrosine. The optimized tal gene can facilitate the construction of phenylalanine metabolism pathway. Different expression vectors used in this study also offered more options for biological production of p-coumaric acid.