Application of rumen microorganisms for enhanced anaerobic fermentation of corn stover

Anaerobic fermentation of corn stover by rumen microorganisms in both batch and semi-continuous cultures was studied. In the batch reactors, a high volatile solids (VS) conversion efficiency of 65–70% was achieved after 240 h incubation at 25–40 °C. The volatile fatty acids (VFA) yield ranged from 0.59 to 0.71 g g−1 VS utilized. Acetate, propionate and butyrate were the main aqueous products with small amounts of i-butyrate and valerate also being produced. Biogas was composed of methane and carbon dioxide. In the semi-continuous reactor, at loading rates of 10–30 g VS l−1 d−1 and 40 °C, a VS conversion efficiency of 65% was achieved as a solids and hydraulic retention time of 96 and 18 h, respectively. The VFA yield varied between 0.56 and 0.59 g g−1 VS utilized. Biogas was composed of hydrogen and carbon dioxide, but was free of methane. The experimental results demonstrate that the anaerobic fermentation of corn stover by rumen microorganisms was able to rapidly degrade the volatile solids and produce useful VFAs with high yields.