Comparison of growth and cellulolytic enzyme production in Aspergillus chevalieri and Penicillium steckii from mouldy cacao beans

Abstract

Aspergillus chevalieri and Penicillium steckii grew best at 30 degrees C and at pH of 6.5-7.5. Among the carbon sources employed, sucrose supported maximum growth of A. chevalieri while glucose was best for P. steckii. Growth of both organisms was optimal on ammonium tartrate as the sole source of nitrogen. A. chevalieri and P. steckii grew in synthetic media containing, respectively, soluble or insoluble cellulose as the sole carbon source, releasing a cellulolytic enzyme into the medium. The enzymes from each organism were separated and partially purified by molecular exclusion and ion-exchange chromatography into two components. There was synergism between the components of enzymes from each organism in that they together released more glucose units from insoluble cellulose than could be predicted from their activities alone. The molar mass of the enzymes estimated from the elution volume on Sephadex was approximately 110 kg/mol for A. chevalieri and 94 kg/mol for P. steckii.