MICROBIAL UTILIZATION OF SOYBEAN WHEY FROM TOFU FACTORY

Abstract

Preliminary study was carried out by using soybean whey (waste water from tofu factories) to cultivate different types of microorganisms in order to produce biomass, biogas, riboflavin and cellulase enzyme. The soybean whey was composed of reducing sugar (0.5 mg/ml), total sugar (5.5 mg/ml) total amino acid (4.1 mg/ml) and total nitrogen (1.62 mg/ml). More than 30 microorganisms isolated from spoiled tofu were grown in soybean whey. The best isolate was yeast which could grow in whey with maximal growth of 2.52 units (OD 660 nm) in one day. The residue from cow - dung biogas plant was used as a starter for producing whey biogas which was done in a litre bottle by semi - batch process. The production rate was 200 ml in 2 days. Eremothecium ashbyii grown in whey for 5 days synthesized 0.09 mg/ml riboflavin. This production rate could be increased to 0.92 mg/ml by adding 14% soybean residue. Lastly, 5 day-old culture of Sporotrichum cellulophilum was able to synthesize 0.78 unit/ml of cellulase and in the addition of 10% soybean residue the cellulase production increased to 1.28 unit/ml.