Simple and efficient enzymatic procedure for p-coumaric acid synthesis: Complete bioconversion and biocatalyst recycling under alkaline condition

p -Coumaric acid (para-hydroxycinnamic acid, p -HCA), as a kind of natural active substance from plant cell walls, is widely used in medicine, food, and cosmetics with its antioxidant, anticancer, and other properties. Biological production of p -HCA can be achieved via one-step deamination of the L -tyrosine by tyrosine ammonia-lyase (TAL). Here, a new highly active TAL ( Fc -TAL) from Flavobacterium columnare was identified via gene mining and heterologous expression . The purified Fc -TAL completely converts 22 mM  L -tyrosine to p -HCA under alkaline condition (pH 9.5–10.0) at 55 °C. To increase enzymatic recyclability and reduce the bioproduction cost, Fc -TAL was immobilized on a silica nanospheres through silica-binding peptides (SiBP2) at pH 10. In comparison to free enzyme , the immobilized TAL SiBP2 exhibited higher stability, over 50% activity was retained even after 10 consecutive catalytic cycles. Further experiments revealed that an aliquot of immobilized enzyme (about 200 mg TAL) can transform 20 g  L -tyrosine into17.8 g p -HCA with 96% yields and 98% purity through 5 consecutive reaction cycles. Our studies not only provided a strategy for enzyme immobilization in alkaline condition, but also developed a green process for p -coumaric acid biosynthesis with the highest conversion rate and yield reported to date.