Nutrition upgrading of corn-ethanol co-product by fungal fermentation: Amino acids enrichment and anti-nutritional factors degradation

Abstract

Corn wet distiller’s grain with solubles (WDGS) used as a feeding ingredient to monogastric animal diets is limited due to its imbalanced key amino acids, high fiber and potential existance of mycotoxins. Fermentation of WDGS by edible fungi has potential of upgrading the feedstock into nutritional and low-risk feeding ingredient for monogastric animals. In this study, four different fungi Aspergillus oryzae, Rhizopus oryzae, Mucor indicus and Trichoderma reesei were employed to ferment the mixture of WDGS and soybean hull at 75/25 ratio at 28°C for 6–9 days. Urea at different concentration was supplied as additional nitrogen source. Results showed that, M. indicus improved total amino acids yield by 13.3% with over 95% consumption of the supplied urea at 1% N. Meanwhile, T. reesei degraded structural polysaccharides by 41% and concentrated amino acids by 19%. In addition, phytate was degraded by 53, 56, 31 and 20% with A. oryzae, R. oryzae, M. indicus, and T. reesei, respectively. Total aflatoxin and deoxynivalenol was detoxified via T. reesei by 52.8% and 92.9%, respectively, while zaeralenone was detoxified via M. indicus by 89.2%. This study demonstrated a feasible way of producing nutritional-improved monogastric feeding ingredient from corn-ethanol plant.