부산대학교 도서관

The purification and characterization of the extracellular polygalacturonase from Zygoascus hellenicus V25 submerged culture using orange peel waste were investigated. This polygalacturonase, with a molecular weight of 75.28 kDa, was purified to 16.89 purification fold with a recovery of 18.46% and specific activity of 2469.77 U/mg protein by ammonium sulfate precipitation, DEAE cellulose chromatography, and Sephadex G-100 gel filtration. The enzyme exhibited maximum activity at 60oC and pH 5.0 and was stable over a wide range of pH levels (3.0-11.0). Moreover, enzyme activity was enhanced by Cu2+ and cysteine, whereas it was strongly inhibited by Hg2+. The extent of enzymatic hydrolysis was negatively correlated with the degree of pectin esterification. Km and Vmax values of the polygalacturonase were 5.44 mg/mL and 61.73 μmol/(min·mg), respectively. The polygalacturonase was applied in the juice clarification of four fruits, and results showed that the percentage transmittance at 660 nm increased by 3.51, 4.36, 8.04, and 12.2%.