MoutaiJiuquis a famous aromatic raw material of Maotai flavor liquor in China. It is brewed at high temperature and contains many kinds of bacteria, molds, and yeasts. There are many useful glycoside hydrolases in these microfloras, from which efficient glycoside hydrolases can be screened for biotransformation of natural saponins. In this study, an alpha-L-arabinofuranosidase gene (CaAraf51, 1524 bp, 507 amino acid, 55.07 kDa, and pI = 4.8) was cloned fromCellulosimicrobium aquatileLyp51, which was isolated from the MaotaiJiuqu. TheCaAraf51 was heterogeneously expressed inE.coliBL21 (DE3) and purified by N-terminal His-tag with the Ni2+-affinity column chromatography. The results show that purifiedCaAraf51 has a 6.8-fold purification factor and specific activity of 15 U/mg. Under optimal conditions (pH 5.0, temperature 40 degrees C), kinetic parametersK(m)ofCaAraf51 forpNP alpha Araf and Rc were 1.1 and 0.57 mM, theV(max)were 25 and 6.25 mu mol/min/mg, respectively. 90% of 0.87 mg Rc substrate can be transformed by 9.6 U purifiedCaAraf51 in 1 mL reaction system under suitable conditions (30 degrees C, pH 7.5 phosphate buffer, 1 h). In addition, we also tested the effects of metal ions and chemical agents on the activity ofCaAraf51. According to systematically studied its function and enzymatic properties,CaAraf51 has excellent value and potential of biotransformation Rc into Rd.