LCR-Pilze - Analysis of the contribution of aerobic fungi to biogas production

Subproject 2: Contribution analysis of aerobic fungi

Because of climate change and geopolitical developments, Germany is striving for a climate-friendly energy supply that is independent of the import of fossil fuels. The production of biogas is based on biomass, a renewable and domestic energy source. These advantages make biogas an important pillar of the German energy mix, which is increasingly based on renewable energy sources. In addition to farm manure, energy crops such as maize are currently used as substrates for biogas production. However, acceptance and state subsidies for energy crops continue to decline. Therefore, biogas operators have to switch to alternative substrates, such as the agricultural coproduct straw.

However, the use of straw as a substrate in biogas plants is associated with difficulties. For example, straw is more difficult to digest compared to energy crops due to its higher lignocellulose content and causes mechanical malfunctions in biogas plants, which lead to a significant reduction in biogas production and additional costs. In order to be able to tap into the potential of straw for biogas production, the use of aerobic (TUM) and anaerobic (LfL) fungi with high cellulolytic activity for the digestion of this lignocellulose-rich coproduct is being investigated in this joint project with the partners Bayerische Landesanstalt für Landwirtschaft (LfL) and INNOVAS BMK GmbH. In a two-stage pilot plant biogas plant, we are researching the extent to which the use of Trichoderma in hydrolysis can lead to a higher biogas yield with straw as a substrate and to a reduction of mechanical disturbances in the anaerobic digester. In the course of the experiments in the pilot plant biogas plant, data will be collected on the process chemistry as well as on the meta-genomes, meta-transcriptomes and proteomes in order to obtain as complete a picture as possible of the influence of Trichoderma on hydrolysis and biogas production as a whole. Fermentation residues resulting from the biogas process are digested in rotting boxes using aerobic brown or white rot fungi in order to make the untapped sugars present in the fermentation residues usable for the anaerobic digester. These digested fermentation residues are to be fed back into the biogas process and their residual potential quantified.

 

Publications

• Young, D., Dollhofer, V., Callaghan, T. M., Reitberger, S., Lebuhn, M., & Benz, J. P. (2018). Isolation, identification and characterization of lignocellulolytic aerobic and anaerobic fungi in one- and two-phase biogas plants. Bioresource Technology, 268, 470-479. doi:https://doi.org/10.1016/j.biortech.2018.07.103