Utilizing residues and closing the loop
The program area bundles research activities on biogas as well as on carbonized biomass such as biochar and humic substances. Residual biomass that might otherwise not be used can thus be used to produce energy sources as well as to improve the soil. Our aim is to further develop and specify the processes of both biological and thermo-chemical conversion of biomass. Both areas constitute an integral part of the circular bioeconomy.
Residuals can originate from animal husbandry systems (program area "Individualized Animal Husbandry"), food production systems (PB "Diversified Crop Production" and "Healthy Foods") as well as from biomaterial production lines (PB "Multifunctional Biomaterials") and also include waste and wastewater from municipalities. One research task is to deal with residual materials of suboptimal, heterogeneous and fluctuating composition and to minimize risks such as the spread of pathogens and pollutants by means of the processes.
Biological and thermo-chemical conversion processes for biogas, hydrochar, humic substances, as well as lactic or succinic acid (program area 'Multifunctional Biomaterials') take place in more or less closed systems. In order to obtain more information about these conversion processes, we are creating models of the processes based on spectral analyses as a prerequisite for future work on digital twins.
In addition to basic research in our specialized, well-equipped laboratories (biogas laboratory, biochar laboratory), we transfer our research approaches to practice. The complexity of the interactions between char-based products, soils, plants and microorganisms requires close, inter- and multidisciplinary cooperation. As a reallab, the Leibniz Innovation Farm offers an ideal platform for this.
Biogas

It is challenging to work efficiently with inhomogeneous feedstocks and feedstocks from different sources that are difficult to ferment. Our focus is on liquid manure, lignocellulosic biomass from landscape management, paludiculture and stalk material. Our objective is to further develop the biogas process in such a way that, despite temporal, qualitative and quantitative variations in the feedstock, the fermentation process is stable with low breakdown susceptibility. In the future, biogas plants should operate in a knowledge-based, information-driven and largely automated manner. To achieve this goal, we are modeling the biogas process as a digital twin.
Improved understanding of the highly sensitive fermentation process, in particular the development of microorganisms, provides the basis needed for this. Microorganisms form microbiomes in the fermenter, complex microbial communities that differ depending on the feedstock, pH, temperature and the timing of the fermentation process. We identify the microorganisms involved in the process at the species level (taxonomic diversity) and determine their metabolic potential (functional diversity).
The broad spectrum of these tasks requires multidisciplinary research from the fields of microbiology and molecular ecology, data science, agricultural and environmental sciences, among others.
Biochars and humic substances

Our research on thermo-chemical conversion of biomass is focused on pyrolysis (for dry feedstock) and hydrothermal carbonisation (moist material). Thermo-chemical treatment can carbonise both lignified and non-lignified biomasses into biochar, protecting them from rapid microbial degradation. The carbon stored in these materials is sequestered. If the process of hydrothermal carbonisation takes place at low pH, the end product is a solid biochar. At higher pH values, humic substances are formed. Both processes, pyrolysis and hydrothermal treatment, have the potential to process raw and residual materials and they can be integrated into agricultural production systems.
With our research in the biochar lab, we are investigating how chars from pyrolysis and hydrothermal carbonisation (HTC) can be used, for example, for carbon sequestration and soil melioration. In order to be able to design the processes efficiently for specific applications in agriculture and environmental protection, it is important to understand the kinetics of thermo-chemical conversion. Against this background, we are investigating the influence of operating and material parameters on process and product. Another research focus is on the effects of pyrochar, hydrochar and humic substances on plant growth and microbial life in the soil. In addition, we are investigating the influence of the use of chars/humic substances on the water storage capacity of the soil, carbon sequestration and emissions.
To the team of the program area
Research projects
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The overall objective of the project is the identification and verification of microbial system condition indicators and the development of process models based on them for trouble-free and demand-oriented process contro…
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The goal of the project is the value-added processing of biomass by novel and advanced technologies to better exploit the environmental and economic potential of biogenic resources. A specific aim is to increase the effi…
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The aim of the joint project bio4value is to develop new types of gas separation membranes and membrane modules for more efficient biogas processing. The aim is to achieve a high quality of the separated material flows a…
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The aim of the joint project is to develop a technically easy-to-implement process for the targeted reduction of greenhouse gas emissions (especially methane and nitrous oxide) during slurry and digestate storage by addi…
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Funding sequencing costs: deciphering the degree of microbial cross-linking within farm manure and biogas microbiomes
More projects within the program area
Publications of the program
- Marzban, N.; Libra, J.; Rotter, V.; Ro, K.; Moloeznik Paniagua, D.; Filonenko, S. (2023): Changes in Selected Organic and Inorganic Compounds in the Hydrothermal Carbonization Process Liquid While in Storage. ACS Omega. (4): p. 4234-4243. Online: https://doi.org/10.1021/acsomega.2c07419 1.0
- Tkachenko, V.; Marzban, N.; Vogl, S.; Filonenko, S.; Antonietti, M. (2023): Chemical Insight into the Base-Tuned Hydrothermal Treatment of Side Stream Biomasses. Sustainable Energy & Fuels. : p. 769-777. Online: https://doi.org/10.1039/D2SE01513G 1.0
- Küchler, J.; Willenbücher, K.; Reiß, E.; Nuß, L.; Conrady, M.; Ramm, P.; Schimpf, U.; Reichl, U.; Szewzyk, U.; Benndorf, D. (2023): Degradation Kinetics of Lignocellulolytic Enzymes in a Biogas Reactor Using Quantitative Mass Spectrometry. Fermentation. (1): p. 67. Online: https://doi.org/10.3390/fermentation9010067 1.0
- Hahn, J.; Westerman, P.; Gerowitt, B.; Heiermann, M. (2023): Mesophilic, anaerobic digestion in a full-scale, commercial biogas reactor kills seeds more efficiently than lab-scale systems. Fermentation. (5): p. 481. Online: https://doi.org/10.3390/fermentation9050481 1.0
- Farru, G.; Libra, J.; Ro, K.; Cannas, C.; Cara, C.; Muntoni, A.; Piredda, M.; Cappai, G. (2023): Valorization of Face Masks Produced during COVID-19 Pandemic through Hydrothermal Carbonization (HTC): A Preliminary Study. Sustainability. (12): p. 9382. Online: https://doi.org/10.3390/su15129382 1.0
- Kohzadi, S.; Maleki, A.; Bundschuh, M.; Vahabzadeh, Z.; Johari, S.; Rezaee, R.; Shahmoradi, B.; Marzban, N.; Amini, N. (2023): Doping zinc oxide (ZnO) nanoparticles with molybdenum boosts photocatalytic degradation of Rhodamine B (RhB): particle characterization, degradation kinetics and aquatic toxicity testing. Journal of Molecular Liquids. : p. 0. Online: https://doi.org/10.1016/j.molliq.2023.122412 1.0
- Heinrich, T.; Kaetzl, K.; Libra, J.; Hoffmann, T. (2023): Influence of Thermochemical Conversion Technologies on Biochar Characteristics from Extensive Grassland for Safe Soil Application. Energies. (4): p. 1896. Online: https://doi.org/10.3390/en16041896 1.0
- Kohzadi, S.; Marzban, N.; Godini, K.; Amini, N.; Maleki, A. (2023): Effect of Hydrochar Modification on the Adsorption of Methylene Blue from Aqueous Solution: An Experimental Study Followed by Intelligent Modeling. Water. (18): p. 3220. Online: https://doi.org/10.3390/w15183220 1.0
- Heinrich, T.; Park, H.; Orozco, R.; Ding, Z.; Álvarez-López, V.; Mosquera-Losada, M.; Steinbeis, L.; Hoffmann, T. (2023): Biochar production from late-harvest grass - Challenges and potential for farm-scale implementation. Sustainable Production and Consumption. (May): p. 256-267. Online: https://doi.org/10.1016/j.spc.2023.02.019 1.0
- Farru, G.; Dang, H.; Schultze, M.; Kern, J.; Cappai, G.; Libra, J. (2022): Benefits and Limitations of Using Hydrochars from Organic Residues as Replacement for Peat on Growing Media. Horticulturae. (4): p. 325. Online: https://doi.org/10.3390/horticulturae8040325 1.0
More publications of the program area