SOAR is a research school. In addition to the focus on PhD students, SOAR also includes graduates, postdocs and supervisors in the activities and networks. This is important because they also constitute the research environment, in which the PhD student is under education. SOAR wants to contribute to the professional discussions with a special focus on the organic food and farming systems.
The research interests of SOAR cover a wide range of subjects within organic agriculture and food systems:
The objective is to design an efficient and environmental friendly bio-refinery from rape plants, with focus on experimental fermentation of cellulosic rape fibres into ethanol. The bio-refinery will be designed partly based on extensive literature review. However, the main part of this study will focus on experimental work, regarding optimization of production of ethanol by cellulosic rape fibres.
This experimental study will cover all upstream production steps of ethanol from straw, including feedstock quality assessment and prospects, physical/chemical pre-treatment of straw, and enzymatic hydrolysis and fermentation (SSF) of fibres. The following tasks will be studied:
Maximize ethanol production by optimizing chemical pre-treatment of the straw fibres, via hydrothermal and Wet-oxidation (WO) techniques.
Maximize the reduced hexose and ethanol yield, and production rate of the pre-treated fibres, by optimizing enzymatic activity of extra-cellular and intra-cellular enzymes.
Increase of ethanol production, by characterizing, controlling and overcoming of degradation products formed during pre-treatment of straw, affecting performance of SSF.
Design of a bio-refinery concept using the rape plant for energy products, by means of a review paper. The review will present up-to-date technologies and solutions that will act as a guide for building a bio-refinery from rape plant, a technical blueprint for European industry.
Background
Fossil fuel depletion and climate change appraised concerns pose high demand to society to increase the use of renewable energy. Most important transportation biofuels nowadays are bioethanol, biodiesel, biohydrogen, bioelectricity, and biogas. Biofuels are by fact produced by renewable resources, such as plant biomass. Given that plant biomass production is energy demanding, by means of cost of land, water, energy, and chemicals, including logistics of transport and storage, it has been made clear that utilisation of the entire crop is essential to maximize efficiency of the process.
Rape is the most common feedstock in the biodiesel production industry. According to FAO, in Europe approximately 17 MT of rape plant and, of which 9.3 MT rape straw were produced (2006). Rape, however, is a nitrogen demanding crop. Furthermore, biodiesel industry utilizes on average 45 % wt. part of the plant, whereas the residues (stems and leaves, collectively called straw) are addressed to animal feed industry or spread back on the cropland.
In a bio-refinery concept, waste streams are, in principle, substrates for subsequent processes, realising a cascade concept where practically nothing is discarded. Finally more than one market goods are produced out of a single starting material. In this way, feedstock is completely valorised.
Regarding prospects of rape straw, different types of straw have been tested for second-generation bioethanol production and other biofuels, due to their abundance, low costs, and co-current environmental benefits. Furthermore, rape straw has a strong potential to produce biofuels, given that it is rich in fermentable carbohydrates, i.e. cellulose and hemicellulose. In a previous study, rape was successfully converted into ethanol by 70 % of the theoretical, after chemical pretreatment with wet oxidation, and subsequent SSF of the cellulose with cellulases and Saccharomyces cerevisiae.
Main focus of this study will be exploitation of cellulosic fraction of rape straw towards ethanol production, although to some extent literature study will cover all the bio-refinery design as a whole. Cellulose polymer will be uncovered by lignin and hemicellulose through physical/chemical pretreatment and cellulose-rich fibres will then be treated in a fed-batch mode with enzymes and ethanol fermenting microorganisms. Cellulases will hydrolyze cellulose into monomer sugars, and thermotollerant/thermophilic yeasts will ferment sugars into ethanol.
