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Grøn Dyst 2016

216 73 3G-bioethanol from abundant seaweeds Marie Blatt Bendtsen Department of Chemical and Biochemical Engineering, Technical University of Denmark I NTRODUCTION The world's storage of fossil fuels is coming short. The demand for alternative energy sources that meet the world’s energy requirement in a sustainable and environmentally friendly manner is great. After decades of first generation bio-fuels, ethanol production from biomass has proven to be a suitable alternative to fossil fuels. The different challenges associated with 1G- and 2G-bioethanol call for a 3rd generation of substrates for bioethanol. Seaweeds are abundant in the oceans worldwide, and might just be what we are looking for. Figure 1: Seaweed on the northern coast of Zealand Figure 2: Seaweed in Mahahual, Mexico THEORY Seaweeds contain a great amount of potentially fermentable sugars. The advantages of using seaweeds compared to terrestrial biomasses are numerous. The cultivation of seaweeds requires no fertilizer, the growth-rate is high and neither freshwater resources nor farming land are exploited. The sustainability is pronounced, but as of now the ethanol yield from fermentations of seaweeds do not reach the 2G-bioethanol benchmark of 40 g ethanol pr. liter. This study looks into why this is, and how to design a pretreatment, enzymatic hydrolysis and fermentation process that allows a sufficient yield of ethanol. METHODS The currently used methods to process seaweeds are designed to process terrestrial biomass and have proven insufficient for seaweeds. The great challenge lies within designing an effective and low-cost process. Pretreatment such as hydrothermal treatment, wet-oxidation, dilute acid hydrolysis are possible choices in combination with enzymatic hydrolysis. The enzymatic hydrolysis can be conducted with various enzyme combinations. For optimal hydrolysis new and more suitable enzymes could be derived from for instance seaweed degrading fungi. Various microorganisms such as S. cerevisiea or ethanogenic E. coli can carry out the fermentation. This literature study will give a qualified suggestion for a new process design of the future 3G-bioethanol. PRODUCTS AND SUSTAINABILITY POSTER IDEA BACHELOR LEVEL COURSE / PROJECT


Grøn Dyst 2016
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