Green tractor – long term solutions for the self sufficiency of organic agriculture based on bio-based fuels
Per-Anders Hansson (project leader)
Summary of results with list of publications from SLU.
Email: per-anders.hansson@slu.se
Organic agriculture in Sweden is estimated to consume at least 36,000 m3 diesel oil annually. In a short time perspective, the technical potential exists to make organic agriculture self sufficient in bio-based fuels. In the longer term, however, a number of new technologies (primarily hydrogen gas and methanol based on vehicles with fuel cells) will be available.
The objective of this work was to describe and analyse the energy, environment and economy related properties of systems with second and third generation fuels. Systems based on agricultural by-products show very advantageous properties.
Production of digestion residues with a high ammonia content
Anna Schnürer (project leader)
Summary of results with list of publictions from Microbiology, SLU.
Email: Anna.Schnurer@mikrob.slu.se
Anaerobic microorganisms can break down various types of organic waste fractions and at the same time produce renewable energy (biogas) and a nutrient-rich degradation product (digestion residue) which can be used as a fertiliser. When protein-rich materials are degraded in a biogas process, hydrogen is released in the form of ammonia or ammonium, which gives hydrogen a form that can be utilised by plants and can increase the nutritional value of the digestate. Unfortunately, high levels of ammonia appear to inhibit the biogas-forming organisms, methanogens, which creates the risk of disruptions and operational problems in the biogas process.
Some biogas processes with high levels of ammonia have exhibited an unusual type of methanogenic pathway, synthrophic acetate oxidation (SAO). Only three SAO bacteria had been known previously, but this project resulted in the isolation of three more, which markedly enhances the possibility of understanding the significance of these organisms for the biogas process and the development of methanogenesis.
The results show that it is possible to run a biogas process with protein-rich material and a high ammonia level, but the process requires a relatively long retention period to be stable. It is also important for the ammonia content to be increased gradually so that the organisms have time to adapt and develop the new methanogenic pathway.
Abiotic stress reactions in plants caused by elevated carbon dioxide levels
Leif Bülow (project leader)
Summary of results with list of publications from Chemistry Centre, LTH.
Email: Leif.Bulow@tbiokem.lth.se
Since industrialisation in the middle of the 19th century, the burning of fossil oil has given rise to elevated carbon dioxide levels, which is predicted to double by 2100 owing to human activities. In the long term, renewable energy sources from plants must therefore replace fossil oil.
In contrast to the burning of oil which produces carbon dioxide and water, plants make use of the chemical process called photosynthesis during which carbon dioxide can be sequestrated and stored in different parts of the plant. Such a storage product is starch which is stored in the green tissue of the plant or in the seed. Another form of storage is oil in which carbon is accumulated effectively.
Today, many plants have limited photosynthetic ability, one of the reasons being that atmospheric oxygen competes with carbon dioxide. With higher levels of carbon dioxide in the atmosphere, plant metabolism is modified and the natural flow of carbon is altered.
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