Pectinolytic enzymes produced by Aspergillus carbonarius (Bainier) thom

Abstract

Aspergillus carbonarius produces exocellular pectinolytic enzymes which are active within the acid range of pH and therefore are useful in commercial processing of fruits. The fungus produces pectin methylesterase, a viscosity-reducing enzyme, and exo-polygalacturonase; but it does not produce transeliminases. The optimum pH range and temperature for the above-mentioned enzyme activities are 3.5 to 4.0 and 50°, respectively. Enzymic hydrolysates of both pectin and pectic acid contained only monogalacturonate. The enzymes are stable at pH 3.0 to 4.5 at room temperature (20-30°) for more than a month. A preliminary purification yielded two fractions, both of which showed viscosity-reducing as well as saccharogenic activities. Pectin methylesterase was unaffected when treated with 6M urea for 5 hr at pH 6.7 and 25°, whereas polygalacturonase and viscosityreducing activities were completely inactivated.