UTILIZATION OF STARCH PROCESSING WASTE-WATER FOR PRODUCTION OF MICROBIAL BIOMASS PROTEIN AND FUNGAL ALPHA-AMYLASE BY ASPERGILLUS-ORYZAE

The production of microbial biomass protein (MBP) and fungal alpha-amy lase from starch processing waste-water (SPW) by a selected strain Asp ergillus oryzae was investigated as part of a comprehensive SPW treatm ent programme. A simple, non-aseptic, one-stage process was successful ly carried out by using ail air lift bioreactor under the optimised gr owth conditions at pH 5.0 and 35 degrees C. Bioproduct yields of 6.1 g /litre of MBP that contained 38% protein, and 55 EU/ml of alpha-amylas e enzyme were obtained from a 12-h batch culture. The pellet bioproduc t led to easy harvesting of the biomass protein. The SPW was treated b y removing 95% COD, 93% BOD and 98% suspended solids, and can be used for farm irrigation. The alpha-amylase had a stable enzyme activity at pH 5-9 and 25-35 degrees C. Pretreatment by hydrolysis and sterilizat ion of SPW and nutrient supplementation may be unnecessary. (C) 1998 P ublished by Elsevier Science Ltd. All rights reserved.