Biofuels from algae : methods and protocols

Algae are simple plants mostly living in aquatic environments. The algal biomass is built during photosynthesis, which transforms CO2 to organic material using light energy. The fact that algae grow in areas not competing with traditional agriculture has led to consider- able interests during the past decades in developing algal biomass into a feedstock for biofuel production. Algae can be divided into microalgae and macroalgae, i.e., seaweed. Macroalgae have been used for centuries as animal feed and fertilizer and grow typically along the coast on hard substrates. Seaweed can also be cultivated, for example, on lines that have been seeded with the desired species and moored at sea. This is already a relatively big industry for agar, alginate and carrageenan production and for direct human consumption e.g. nori produc- tion. Macroalgae are relatively high in carbohydrates and low in lipids and in terms of biofuel best suited for ethanol production. Microalgae are unicellular, microscopic organisms that reproduce by cell division. They are characterized by high metabolic rates compared to higher plants, due to their efficient surface/volume ratios and lack of supporting structures. They may consequently have a very high maximum growth rate (>1/day), and some species have beneficial cellular composition for biofuel production. In particular the high lipid content in some species has gained attention as potential feedstock for biodiesel production. This book provides an overview of different ways to grow algae and the methods for how to start algal cultivation, monitor algal growth, environmental impact of its cultivation, and a range of methods for characterizing the biomass. The first chapters are intended for those not familiar with algal cultivation and provide step-by-step instructions for how to isolate and get the algae to grow. This is followed by chapters describing how to use fluorescence techniques for estimating algal biomass and lipid content. Using fluorescence as a proxy for biomass or lipids has the advantage that it can be done rapidly at a fraction of the price of more traditional analytical methods, and therefore suitab le for small-scale algal cultivation. The last part of the book contains protocols for determination of, e.g., carbo- hydrates and lipids in algal biomass, which require an advanced laboratory to carry out.