Impact of Mycotoxins and Moldy Maize Silage on the Biogas Process

Abstract

The objective was to find out if moldy maize silage has a negative influence on the biogas process. For this, various mycotoxins and moldy maize silage were examined in batch digestion tests and in a laboratory biogas plant with two parallel fermenters. The moldy silage was produced under controlled laboratory conditions. The results show that mycotoxin concentrations, which were even higher than described in the literature for moldy grain and silage, had no inhibitory effects on the biogas production. Continuously running fermentation using moldy maize silage as a sole substrate resulted in reduced biogas yields compared to non-moldy maize silage. By means of an extended substance group analysis, a significant decrease of easily digestible carbohydrate content was found in the moldy maize silage. Feeding moldy maize silage can lead to reduced biogas yields due to the changed composition of the substrate, but the biogas process is not significantly affected.

Keywords: maize, mycotoxins, Biogas, Biodegradation, fermentation