Protein separation and characterization from Neochloris Oleoabundans

18 
 
In the second generation of biofuels, researches were focused on the conversion of the cellulose 
into glucose by enzymes and the further fermentation of the obtained sugars to ethanol. Many 
raw materials that were used for the production were lignocellulosic materials such as straw, 
wood and grass. Another route was gasification of agricultural residues to obtain syngas (mainly 
CO and H
2
) then used for Fischer Tropsch applications or methanol production, and pyrolysis of 
agricultural residues. In the third generation efforts have been focused on microalgae and 
especially on how to produce bioethanol, biodiesel and hydrogen from microalgae (Dragone & 
Fernandes, 2010). The third generation is represented by biofuels produced by microalgae. 
Microalgae are cell factories that convert CO
2
 to primitive compounds that can be processed to 
produce biofuels, foods, feed and other high value bioactives. Microalgae produce several 
biofuels such as methane obtained by anaerobic digestion of biomass and biodiesel from 
microalgal oil. Biodiesel is commercially produced from plant and animal oils, but the option of 
manufacturing it from microalgae is now taken into account more seriously due to the 
enhancing petroleum price (Chisti, 2007). 
1.1 Microalgae 
Microalgae are small plant-like organisms having a size of 1-50 micrometres in diameter. They 
make part of the aquatic biomass together with macroalgae and large aquatic plants. There are 
hundreds of thousands of existing microalgal species but just a few tens of thousands have been 
described in literature. They live both in freshwater and seawater and a single cell cannot be 
seen with naked eye, but usually when the concentration increases they turn the water colour to 
green, brown blue or orange (Fig. 1.2). Most species contain chlorophyll, so they can use sunlight 
to convert carbon dioxide into oxygen and biomass. Many products make part of the biomass, 
such as fatty acid, proteins, colorants, anti-oxidants and starch that can all be used in many 
everyday utilities (Pulz & Gross, 2004). 
 
 
 
Fig.1.2 On the left an example of microalgae cultivation. On the right some fed-batch reactors of different varieties of 
microalgae. 
Microalgae need a specific living setting to perform the highest productive condition. They 
should be exposed to light and the medium should provide the right compounds in the right