P109: Characterization of different tyrosine ammonia lyase enzymes (TAL) and their impact on phenylpropanoid production

Phenylpropanoids (such as flavonoids and stilbenes) are a large and heterogeneous group of phenolic acids, a class of plant secondary metabolites with numerous potential industrial applications, including commercial aromas, colors, other food additives, nutraceuticals and medicines. In plants, flavonoids (such as Apigenin) and stilbenes (such as Resveratrol) are synthesized from aromatic amino acids via the phenylpropanoid pathway (PP pathway). A key step in the PP Pathway is the conversion of these aromatic amino acids to propanoic acids such as p-coumaric acid. This step is catalyzed by a superfamily of ammonia lyases including phenylalanine ammonia lyase (PAL) and tyrosine ammonia lyase (TAL). Unlike PAL, which has been shown to need post-translational modification (not available in bacteria), TAL has been identified in several bacterial species Here we characterize and compare the functionality of well-known as well as newly discovered TAL enzymes isolated from various organisms, by heterologous expression in Escherichia coli. We characterize them under different cultivation conditions relevant to industrial processes and discuss their possible impact on microbial production of flavonoid compounds.