Protein separation and characterization from Neochloris Oleoabundans

17 
 
1.INTRODUCTION 
Since the last decades, many efforts have been spent in the direction of green fuels and 
reduction of CO
2
 emissions. A strong investment in researches in this field has been needed due 
to the limited amount of available petroleum in the oil fields and to the increasing temperature 
of the Earth. Anyway, research efforts may be not enough if the human and politic sensibility do 
not help the spread of results and methodology to improve production systems.  
Since a couple of decades the term “biofuels” has started its wide-spread among the world. The 
aim of the companies that produce these “biofuels” is to make economically affordable fuels 
from renewable resources.  The US Council in 2000 defined the term biomass as “organic matter 
that is available on a renewable or recurring basis (excluding old growth timber), including 
dedicated energy crops and trees, agricultural food and feed crop residues, aquatic plants, wood 
and wood residues, animal wastes, and other waste materials”. A significant improvement has 
taken place in biofuels field and that is why a clarification about their stages of progress is 
needed.  The first difference is about the utilization: primary biofuels consist on biomass (wood, 
pellets, vegetable wastes) that is burnt to produce heat. Instead of a direct utilization, secondary 
biofuels are obtained from chemical processes and they have a further classification in three 
different classes (Naik, Goud, Rout, & Dalai, 2010). The first generation of bio-fuels has been 
intended to produce fuels from corn starch for producing bio-ethanol but the economic value of 
the product is just slightly higher than all the production costs (Bounds, 2007). The first way to 
produce oil was by a thermochemical process called pyrolysis. In this process the biomass is 
heated at 500-800°C in absence of oxygen: in this way many products could be observed like 
acidic oils, that need further treatments, charcoal and sub-products such as CO
2
 and H
2
O. 
Pyrolysis has not been used for long time because the efficiency was around 50% and it was not 
profitable. Gasification is another thermochemical process, but it is not meant to produce oil 
from biomass. It has been largely used in syngas (mixture of CO and H
2
 and traces of CO
2
) 
production. The process consists in a high temperature treatment of biomass with air and water 
steam. The products are mainly CO and H
2
 that could be used directly in turbines or for the 
synthesis of chemicals such as methanol, dimethyl ether and Fischer Tropsch Diesel. Another 
example is the transesterification of vegetable oil to produce bio-diesel that consists on the 
mixture of esters produced by this chemical process. The best known process is FAME (Fatty 
Acid Methanol Esterification, Fig. 1.1). For this purpose rapeseeds and soy were used and 
chemically transterified to produce biodiesel. Many efforts were also spent to produce biodiesel 
by transesterification of cooking oil and waste of animal fats.  
 
Fig.1.1. The figure represents the FAME process (Chisti, 2007)