Structure and function of a novel fungal enzyme, lactonohydrolase, and its application to optical resolution of pantolactone

真菌内酯水解酶催化D-泛酰内酯分子内酯键的立体定向水解，可用于外消旋泛酰内酯的光学拆分。通过在多种微生物中的筛选，发现在镰刀菌属、赤霉菌属和圆柱状真菌属的几种丝状真菌中都发现了这种立体特异的水解反应的高活性。尖孢镰刀菌AKU 3702表现出较高的产酶能力，且含有该酶的菌体可重复用于该酶的水解反应。该菌在3%甘油、0.5%多肽、0.5%酵母膏和0.5%玉米浆中培养的菌丝体，pH为6.0，水解率为46.0%，生成的泛酸光学纯度为96%D-异构体对映体过量。

A fungal lactonohydrolase catalyzes the stereospecific hydrolysis of the intramolecular ester bond of D-pantoyl lactone and is useful for optical resolution of racemic pantoyl lactone. High activity of this stereospecific hydrolysis reaction was found in several filamentous fungi belonging to the genera Fusarium, Gibberella and Cylindrocarpon through the screening in a variety of microorganisms. Fusarium oxysporum AKU 3702 showed high productivity of the enzyme and the cells containing the enzyme could be used repeatedly for this hydrolysis reaction. On incubation with the mycelia of this fungus, which had been cultivated in 3% glycerol, 0.5% Polypepton, 0.5% yeast extract and 0.5% corn steep liquor, pH 6.0,46.0% of the recemic pantoyl lactone (700 mg/ml) was hydrolyzed and the optical purity of the pantoic acid formed was 96% enantiomeric excess for the D-isomer.