Solid Substrate Fermentation of Cactus Pulp by Aspergillus Niger

Abstract

A new method of culture is described to study the growth of Aspergillus niger on cactus pulp in the solid-state. After extraction of viscous polyelectrolytes, employed in water treatment, the pulp of Cereus peruvianus was used as a substrate for solid-state fermentation by a wild strain of A. niger . The good conditions for A. niger growth were 60 % moisture, initial pH 3.0, 35 °C, a nitrogen source made of 11 % ammonium and 2 % urea (on a nitrogen basis), 5 % potassium phosphate, and 3.2 g spores/100 g substrate. Related to the dry pulp, maximum fungal growth was observed after 120 hours of fermentation with 14 % of protein production.