Mandelic acid and its derivatives are an important class of chemical synthetic blocks, which is widely used in drug synthesis and stereochemistry research. In nature, mandelic acid degradation pathway has been widely identified and analysed as a representative pathway of aromatic compounds degradation. The most studied mandelic acid degradation pathway from Pseudomonas putida consists of mandelate racemase, S-mandelate dehydrogenase, benzoylformate decarboxylase, benzaldehyde dehydrogenase and downstream benzoic acid degradation pathways. Because of the ability to catalyse various reactions of aromatic substrates, pathway enzymes have been widely used in biocatalysis, kinetic resolution, chiral compounds synthesis or construction of new metabolic pathways. In this paper, the physiological significance and the existing range of the mandelic acid degradation pathway were introduced first. Then each of the enzymes in the pathway is reviewed one by one, including the researches on enzymatic properties and the applications in biotechnology as well as efforts that have been made to modify the substrate specificity or improving catalytic activity by enzyme engineering to adapt different applications. The composition of the important metabolic pathway of bacterial mandelic acid degradation pathway as well as the researches and applications of pathway enzymes is summarized in this review for the first time.

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细菌扁桃酸降解途径及其在生物技术中的应用

扁桃酸及其衍生物是一类重要的化学合成嵌段，广泛应用于药物合成和立体化学研究。在自然界中，扁桃酸降解途径作为芳香族化合物降解的代表性途径已被广泛鉴定和分析。恶臭假单胞菌中研究最多的扁桃酸降解途径由扁桃酸消旋酶、S-扁桃酸脱氢酶、苯甲酰甲酸脱羧酶、苯甲醛脱氢酶和下游苯甲酸降解途径组成。由于能够催化芳香底物的各种反应，途径酶已广泛用于生物催化、动力学拆分、手性化合物合成或新代谢途径的构建。本文首先介绍了扁桃酸降解途径的生理意义和存在范围。然后对该途径中的每一种酶进行一一回顾，包括酶学性质的研究和在生物技术中的应用，以及通过酶工程改变底物特异性或提高催化活性以适应不同应用所做的努力。