Bioethanol production from biomass of marine microalgae with yeast

Conference poster, 2011

The world-wide demand for renewable energy sources has put focus on the use of biomass as raw material for biofuel production. To date, plant material has been used to produce bioethanol and biodiesel from carbohydrates and lipids, respectively. Since microorganisms often have a high growth rate and can be grown on non-food producing lands, microalgal biomass has the potential to provide these compounds for production of fuels. In addition, using marine species one can avoid using limited fresh water supplies. In this research project, we aim to use biomass of marine microalgae as a carbohydrate-rich feed stock for bioethanol production by yeast. Algal species with a carbohydrate storage compound suitable for further ethanol fermentation will be identified. Since storage compounds are accumulated at nutrient limiting conditions, optimal culture conditions can be selected to obtain an algal biomass with high carbohydrate content. To achieve this, the effect of nutrient limitation and intensity of illumination on content of carbohydrates, lipids and proteins in biomass will be studied for selected marine species. In our preliminary experiments it has been found that some “carbohydrate” algal species could accumulate carbohydrates to a 2-4 times higher level at nitrogen limiting conditions compared to balanced medium. After obtaining an algal biomass with optimal composition the down-stream processing will be developed to allow efficient hydrolysis releasing fermentable sugars and subsequent fermentation by yeast.