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Protein separation and characterization from Neochloris Oleoabundans

The production of proteins from microalgae was investigated to find sub products with an exploitable market value.
Water soluble proteins from three different strains (Neochloris Oleabundans, Chlorella vulgaris and Desmodesmus) were examined. pH range of highest precipitation (80%, 76%, 89%) was
found around 3.5. Anionic Exchange Chromatography was used as the separation system for
microalgae’s proteins. A mixture of amines solutions was used as eluent between pH 3 and 10.5.
Unlikely the titration curves several proteins eluted at very high pH (> 10.0). For Neochloris Oleabundans most part of proteins, according to chromatograms, eluted in the first 150 minutes (10.5Based on the experimental results and on literature data, two processes have been designed for the production and separation of RuBisCO from microalgal biomass.

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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)

Tesi di Laurea Magistrale

Facoltà: Ingegneria

Autore: Michele Zilocchi Contatta »

Composta da 105 pagine.


Questa tesi ha raggiunto 34 click dal 11/06/2013.

Disponibile in PDF, la consultazione è esclusivamente in formato digitale.