Related Experiment Video
Updated: Feb 4, 2026

Topical Application Bioassay to Quantify Insecticide Toxicity for Mosquitoes and Fruit Flies
Published on: January 19, 2022
Purification and characterization of exo-polygalacturonase from Zygoascus hellenicus V25 and its potential
Xiaohua Lu1, Jianguo Lin1, Changgao Wang1
1Key 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. 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%.
Related Concept Videos
Fruit Development, Structure, and Function
Pancreatic Juice and Secretion
When acidic chyme from the stomach enters the duodenum, it triggers the release of secretin, a hormone that prompts pancreatic juice secretion. After a fatty meal, cholecystokinin, another hormone, stimulates gallbladder contraction and enhances enzyme-rich...
Potential Energy
Chemical bonds that form attractive forces between atoms also contain potential energy, called chemical energy. When a chemical reaction...
Potential Energy
Standard Electrode Potentials
Cell Potential and Free Energy
Thermodynamics is the branch of physics dealing with the relationship between heat and other forms of energy. In an electrochemical cell, chemical energy is converted into electrical energy.
Thus, a link can be predicted between cell potential, free energy change, and the equilibrium constant for the reaction. Cell potential can also be measured as the oxidant or the reducing strength, and similar acid-base strength measures are reflected in equilibrium...

