Purification and characterization of exo-polygalacturonase from Zygoascus hellenicus V25 and its potential application in fruit juice clarification

Xiaohua Lu; Jianguo Lin; Changgao Wang; Xin Du; Jun Cai

doi:10.1007/s10068-016-0215-3

Purification and characterization of exo-polygalacturonase from Zygoascus hellenicus V25 and its potential application in fruit juice clarification

Food Sci Biotechnol. 2016 Oct 31;25(5):1379-1385. doi: 10.1007/s10068-016-0215-3. eCollection 2016.

Authors

Xiaohua Lu¹, Jianguo Lin¹, Changgao Wang¹, Xin Du¹, Jun Cai¹

Affiliation

¹ Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Hubei University of Technology, Wuhan, 430068 China.

Abstract

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 60°C 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. K_m and V_max 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%.

Keywords: Zygoascus hellenicus V25; characterization; exo-polygalacturonase; juice clarification; purification.