Sondersammlungen

Permanent URI for this communityhttps://hohpublica.uni-hohenheim.de/handle/123456789/7011

Browse

Browsing Sondersammlungen by Sustainable Development Goals "7"

Type the first few letters and click on the Browse button
Now showing 1 - 2 of 2
  • Thumbnail Image
    Publication
    Effect of liquefaction temperature and enzymatic treatment on bioethanol production from mixed waste baked products
    (2025) Almuhammad, Mervat; Kölling, Ralf; Einfalt, Daniel; Almuhammad, Mervat; Yeast Genetics and Fermentation Technology, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstraße 23, 70599, Stuttgart, Germany; Kölling, Ralf; Yeast Genetics and Fermentation Technology, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstraße 23, 70599, Stuttgart, Germany; Einfalt, Daniel; Botanical Garden, Ulm University, Hans-Krebs-Weg, 89081, Ulm, Germany
    This study investigates the effect of different liquefaction temperatures (50–70 °C) and four commercial enzyme formulations on glucose release and subsequent ethanol yield, using mixed waste baked products as a substrate. Among the enzymes tested, Amylase GA 500 proved to be superior in the hydrolysis of starch at lower temperatures (50 °C and 55°C). At higher liquefaction temperatures (65 °C and 70°C) all four enzyme preparations showed comparable activity. The highest glucose concentration (205.7 g/L) and the highest ethanol yield (92 g/L) were achieved with Amylase GA 500 at 65 °C. Its superior performance is attributed to the synergistic activity of α-amylase and glucoamylase, which facilitates efficient starch hydrolysis. Crucially, we discovered that the liquefaction temperature profoundly affects fermentation speed independently of the initial glucose concentration or the enzyme preparation used for starch hydrolysis. This novel mechanistic insight suggests that higher temperature treatment either makes an additional factor crucial for yeast fermentation available or depletes/destroys an inhibitor present in the complex waste bakery product matrix. These findings highlight the critical role of temperature and enzyme formulation in optimizing bioethanol production from bakery waste, supporting the development of more sustainable and efficient waste-to-biofuel processes.
  • Thumbnail Image
    Publication
    Innovative process chain for the resource-efficient production of biomethane-based fuels
    (2024) Holl, Elena; Lemmer, Andreas
    Biogas is a key component in renewable energy production and holds significant potential for achieving Germany’s climate goals. In the transport sector, where the share of renewa-ble energy was only 6.8% in 2023, greenhouse gas (GHG) emissions must be reduced from 147.9 Mt in 2022 to 84 Mt by 2030. Biomethane-based fuels such as bio-LNG and bio-CNG are promising alternatives that are compatible with existing infrastructure and vehicle technologies, already contributing to emission reductions. This study aims to optimize biomethane production through an innovative process chain for decentralized and resource-efficient provision of methane-based fuels. Biogas production was analyzed using two-stage anaerobic digestion (TSAD) to determine optimal substrate compositions and operating parameters. Biogas upgrading was conducted via biological hydrogen methanation (BHM), a power-to-gas technology that enhances process efficiency and economic viability. The results demonstrate that TSAD achieves high methane content (> 60%) even under high organic loads, while BHM performance can be further improved through pressure and temperature optimization. A life cycle assessment (LCA) confirms the efficiency gains of the new process chain compared to conventional methods. The use of renewable energy in process stages has the greatest impact on reducing GHG emissions. Decentralized bio-LNG production from agricultural residues emerges as a feasible solution for producing CO₂-negative fuels.