Converting the Lignocellulosic Feedstock into Gaseous Bioenergy through Efficient Anaerobic Digester and Bio-based Fiber Products Derivate

• Applicant: Dr. Benedikt Hülsemann
• Subject Area: Biological Process Engineering ; Biomaterials ; Ecology of Land Use ; Plant Cultivation, Plant Nutrition, Agricultural Technology
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 528509155

The substitution of fossil raw materials with biogenic raw materials for material applications is an essential step towards reducing anthropogenic CO2 emissions. In this context, biomass should be used as holistically and efficiently as possible in the sense of the bioeconomy in order to maximize land efficiency and the contribution to climate protection. The high-quality utilization of agricultural residues, which have hardly been used to date, is a promising way to increase efficiency. However, the material use of agricultural residues is problematic. Biogenic materials always have a fluctuating product quality. Therefore, pretreatment and separation of the residues into usable components is necessary and a crucial step for further utilization. Germany and Taiwan represent two technology leaders with high environmental awareness in their respective climate zones. Germany is located in the temperate climate zone, while Taiwan is located in the (sub-)tropical climate zone. articularly promising agricultural residues that are suitable for material use and will therefore be investigated are cereal straw in the temperate climate zone and cocoa and banana peels as well as rice straw in the (sub-)tropical climate zone. In addition, tomato plant residues are produced in both climate zones. In the project, the agricultural residues are first digested in a hydrothermal treatment process to separate the anaerobically poorly degradable fibers from the very easily fermentable components. This is realized in Germany with steam explosion and in Taiwan with the supercritical water method. his is followed by separation in a liquid/solid separator. The fiber-rich solid is to be used as a peat substitute and as a substrate for microbial cellulose production. Peat is mainly used in horticulture as it has several advantages. However, peat forms very slowly in peatlands and the CO2-binding peatlands have to be drained for extraction. The project will investigate the extent to which the fibers produced can replace peat. A second approach to be investigated in the project is to use the solid fraction as a nutrient medium for bacterial cultures that produce targeted microbial cellulose. The liquid will be used to produce energy using innovative two-stage biogas plants. The use of the organics for biogas production is to provide the process energy of the energy-intensive treatment. The TS content of the liquid fraction is very low, which implies a long residence time and thus a very large reactor volume in conventional fully mixed reactors. To reduce these disadvantages, two-stage reactor systems are being investigated in the project. While in Taiwan both fermenters are operated fully mixed, the methane reactor in Germany is designed as a fixed bed fermenter.

• DFG Programme: Research Grants
• International Connection: Taiwan
• Partner Organisation: National Science and Technology Council (NSTC)
• Co-Investigators: Privatdozent Dr. Andreas Lemmer; Dr. Hans Oechsner
• Cooperation Partners: Professorin Dr.-Ing. Ya-Yu Chiang; Professorin Dr. Yi-Hsin Chien; Professor Dr. Chen-Yeon Chu