Utilization of tomato pomace as a substrate for neutral protease production by Aspergillus oryzae 2220 on solid-state fermentation

Neutral protease production under solid-state fermentation was investigated by Aspergillus oryzae NRRL 2220, using tomato pomace as substrate and enzyme inducer. This substrate is composed of more than 52% of insoluble fiber, more than 20% of protein, 6.52% of ash and other organic materials. This is used as support and nutrients for the microorganism. Initial cultures were performed in conical flasks. Best protease production was obtained after 72 hrs, with 50% initial moisture content, pH of 6 and 1 ml (2 x 107 spores) of 5 days inoculum. Enrichment with soy bean flour induces an increasing of 66.5% of protease activity. The production of protease in pilot bioreactor yielded 12 U/gds after 42hrs of culture. It was enhanced by 13% with a superior result of protease activity (13.55 U/gds) using tomato pomace without enrichment. The present work indicates the potentiality of this waste for fermentation use especially for fungal protease production.