Department of Chemical and Biochemical Engineering, Technical University of Denmark, Kgs Lyngby, Denmark.
Cysbio, Hørsholm, Denmark.
Biotechnol J. 2023 Nov;18(11):e2300111. doi: 10.1002/biot.202300111. Epub 2023 Aug 4.
p-Coumaric acid (pCA) can be produced via bioprocessing and is a promising chemical precursor to making organic thin film transistors. However, the required tyrosine ammonia lyase (TAL) enzyme generally has a low specific activity and suffers from competitive product inhibition. Here we characterized the purified TAL variants from Flavobacterium johnsoniae and Herpetosiphon aurantiacus in terms of their susceptibility to product inhibition and their activity and stability across pH and temperature via initial rate experiments. FjTAL was found to be more active than previously described and to have a relatively weak affinity for pCA, but modeling revealed that product inhibition would still be problematic at industrially relevant product concentrations, due to the low solubility of the substrate tyrosine. The activity of both variants increased with temperature when tested up to 45°C, but HaTAL1 was more stable at elevated temperature. FjTAL is a promising biocatalyst for pCA production, but enzyme or bioprocess engineering are required to stabilize FjTAL and reduce product inhibition.
对羟基肉桂酸（pCA）可通过生物加工生产，是一种很有前途的有机薄膜晶体管化学前体。然而，所需的酪氨酸氨裂解酶（TAL）通常具有较低的比活性，并受到竞争性产物抑制。在这里，我们通过初始速率实验，从黄杆菌和橙色硫细菌中纯化的 TAL 变体进行了对产物抑制的敏感性、活性和在 pH 值和温度范围内的稳定性进行了表征。结果表明 FjTAL 的活性比以前描述的更高，对 pCA 的亲和力相对较弱，但建模表明，由于底物酪氨酸的低溶解度，产物抑制仍将是工业相关产物浓度下的问题。两种变体的活性在测试温度高达 45°C 时都随着温度的升高而增加，但 HaTAL1 在高温下更稳定。FjTAL 是一种很有前途的 pCA 生产用生物催化剂，但需要对酶或生物过程进行工程改造，以稳定 FjTAL 并减少产物抑制。
