Browsing by Subject "Biodiesel"

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    Feasibility of microbial biodiesel and carotenoid production considering the potential of food processing wastewaters as low cost carbon sources using the example of red yeast Rhodotorula glutinis
    (2013) Braunwald, Teresa; Claupein, Wilhelm
    Due to the increasing demand for sustainable biofuels, microbial oils as feedstock for the transesterification into biodiesel have gained scientific and commercial interest. Also microbial carotenoids have a considerable market potential as natural colorants. Against this background this thesis assessed the feasibility of biodiesel produced by heterotrophic microorganisms, particularly yeasts, using the example of oleaginous red yeast Rhodotorula glutinis. To improve the economic efficiency of this process, several studies have been conducted in order to test (i) whether wastewaters from the agricultural processing industry can be utilized as low-cost carbon and nutrient source for growth and lipid production by R. glutinis and (ii) if they also facilitate the simultaneous production of beta-carotene and other carotenoids as high-value by-products. It has been shown at a small scale, that agricultural processing wastewaters can be used as feedstock for the microbial production of lipids and carotenoids. The general discussion continues to assess the approach of microbial biodiesel production in a broader context in terms of its economic, environmental and energetic performance. The calculated break-even price of microbial oil, excluding the cost of the carbon source for fermentation, is around double the price of conventional plant oils as competing products. To reduce the costs, cultivation in open raceway ponds was proposed, which led to a cost reduction of around 20 %. In order to assess the potential environmental benefits different life cycle assessments from algae biodiesel production, which share common features with the proposed process, have been analyzed. It was concluded, that microbial biodiesel cannot outperform common 1st generation biodiesel in terms of GHG emissions, whereas factors of eutrophication potential and land competition could be significantly improved. The high climate relevant emissions were mainly driven by the high energy requirements connected to the extraction of microbial oil, which also puts a heavy burden on the energetic efficiency of the process. Considering the potential of continued research and technical development along with the political commitment to promote 2nd and 3rd generation biofuels, it was concluded, that in the long term microbial biodiesel could become a commercial reality above laboratory and pilot scale. Due to the different restrictions this will probably not happen within the next 20-30 years. Contrary to biodiesel, carotenoids are high-value products, with beta-carotene yielding around US$ 600 per kg. Sustained by this high price and allowing for certain improvements regarding beta-carotene yields and extraction techniques, it can be possible to economically and sustainable produce beta-carotene from R. glutinis in the near future.
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    Sustainable bioenergy cropping concepts : optimizing biomass provision for different conversion routes
    (2014) Mast, Benjamin; Claupein, Wilhelm
    Today energy from biomass already contributes to a considerable share to the global energy consumption. In particular, certain modern bioenergy streams like biogas, biofuels for transportation etc., are of increasing relevance. However, several of the beneficial aspects, which were initially attributed to the utilization of today’s bioenergy, had to be relativized and the controversies regarding environmental and socio-economic drawbacks have, in the meanwhile, been on the rise. Alongside a shift to advanced conversion technologies, the improvement of bioenergy cropping systems towards a sustainable biomass provision is a key element of future bioenergy production. Against this background, the present thesis assessed various aspects in terms of biomass production, biomass provision and biomass conversion mainly addressing the two bioenergy streams – 2nd generation biofuels and biogas. For biogas, the thesis addresses aspects regarding the development of alternative cropping systems, the evaluation of novel crops for biogas purpose, and the assessment of regional biogas potentials using a crop growth model. The second focus of the thesis was set on biofuels while special attention was given to the production of microbial biodiesel, and the characterization and evaluation of potential feedstocks for this purpose.
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    Die Verbreitung neuer Technologien am Beispiel von Biokraftstoffen in Deutschland
    (2010) Benignus, Isabell; Ahlheim, Michael
    By now, Biofuels became an inherent part of the German strategy to fulfil the climate targets of the Kyoto protocol as well as the reduction of the high dependency of power supply from foreign countries. However, Biofuels will only be able to deploy a material effect if their market share increases significantly over the next few years. In Germany, the market share of biofuels is still below ten percent. From a global view the market share is even smaller. The diffusion of biofuels is a problem of the diffusion of new technologies, which covers both the demand side and the production technologies of the supply side. The intention of the work is the analysis of the diffusion of biofuels from a political-economical point of view. The substantial theoretical results of the economic diffusion research are clarified using a neoclassical model and illustrated using the example of the German biofuels market. The work shall contribute to the ongoing discussion on the promotion of biofuels. Accordingly, the focus of the work is application-oriented. The three focal points of the work are: 1. Identification of relevant diffusion constraints of biofuels and analysis of their effects by means of a neoclassical diffusion model. 2. Analysis of the eligibility for support of biofuels. A special focus lies on the question of suitability of different promotion instruments. 3. Empirical examination of the diffusion effect of selected national promotion instruments on the German biodiesel market. A special focus lies on the most important instrument for the promotion of biodiesel: (partial) the energy tax exemption for biodiesel in Germany.