Characterization of the Lipid Components in <i>Desmodesmus</i>and <i>Scenedesmus</i>Strains: Lipid Content, Lipid Classes and Fatty Acid Profile

The lipid composition in terms of the amount of neutral lipids, free fatty acids and polar lipid content is of great importance to make full use possible of this fraction and to define the suitability of its application, either as a raw material for fuel production, nutraceutical purposes or feed. In addition to the fatty components present in the lipid extract, other components may be included, such as: carotenoids, pigments and sterols. The microalgae studied in this work, Scenedesmus sp. and Desmodesmus sp., were subjected to the same growth conditions and evaluated for lipid content, quantification and diversity of lipid components as well as its fatty acid profile. For lipid determination two extraction methods were compared: the J: Schmid-Bondzynski-Ratzlaff and Bligh & Dyer method. For Desmodesmus sp. 5.43% ± 0.41% and 9.18% ± 0.33% of lipids were obtained on an ash-free dry weight basis and for Scenedesmus sp. 12.46% ± 0.38% and 8.16% ± 0.42% of lipids were obtained on an ash-free dry weight basis using for both methods J: Schmid-Bondzynski-Ratzlaff and Bligh & Dyer, respectively. For the identification of the main lipid components present in the extracts, the Thin layer chromatography (TLC) technique was used. This made it possible, using a simple and inexpensive method, to identify the compounds extracted by different extraction methods, that is, it was possible to verify the selectivity of the different extraction methods. In addition, it has been shown that using these methods, widely described in the literature as methods of extracting lipids in practice, extracts a wide diversity of compounds. The major lipid class for both microalgae was fatty acids with amounts between 23.62% - 38.02%. The triglycerides percentage in biomasses without chemical treatment did not exceed 18.26%. In the lipid extract obtained with Bligh & Dyer, the microalgae Desmodesmus sp. presented 55.26% of unsaponifiable material, higher than the amount present using the same extraction method for Scenedesmus sp. 49.06%. Among the main unsaponifiables identified are hydrocarbons (carotenes) and sterols esters. The acid treatment of biomass, method J: Schmid-Bondzynski-Ratzlaff, showed selectivity of 72.84% and 76.66% for obtaining fatty material from the microalgae Desmodesmus sp. and Scenedesmus sp., respectively. The results showed that depending on the method used for extraction, the lipid fraction will be different in relation to the percentage of fatty components.

Quantification of Lipid Content and Identification of the Main Lipid Classes Present in Microalgae Extracts Scenedesmus sp. for Obtaining Fatty Compounds for Biofuel Production

Microalgae biomass has been reported in the literature as one of the most promising sources for obtaining different products of industrial interest such as lipids, fatty acids, carotenoids, proteins and fibers. The lipid fraction of microalgae comprises neutral lipids, free fatty acids and polar lipids. It is of great importance to estimate the composition of the lipid fraction to define the potential for use, either as a raw material for the production of biofuels or for use for nutraceuticals and/or food purposes. The microalgae Scenedesmus sp. cultivated in a photobioreactor, the sky open raceway type, was evaluated for lipid content, identification and quantification of lipid components obtained from different extracts. In the quantification of the lipid content, extraction methods were proposed without chemical treatment (use of solvents only) such as chloroform:methanol (2:1 v/v)—Bligh & Dyer, Ethanol, Ethyl acetate:Hexane (1:1 v/v) and others with chemical treatment such as J-Schmid-Bondzynski-Ratzlaff (acid) and saponification (basic). For the identification of the main lipid components present in the extracts, the Thin layer chromatography (TLC) technique was used. This made it possible, using a simple and inexpensive method, to identify the compounds extracted by different extraction methods, that is, it was possible to verify the selectivity of the different extraction methods. In addition, it has been shown that using these methods, widely described in the literature as methods of extracting lipids in practice, extracts a wide diversity of compounds. The levels of lipids obtained via solvent extraction were up to 50% higher than those obtained with chemical treatment. In lipid extracts, obtained via solvent extraction, the presence of polar compounds, glycerides, carotenoids, pigments and sterols was identified, with up to 53% being composed of an unsaponifiable fraction, thus, presenting low selectivity for extracting fatty components. The acidic and basic treatments applied to the biomass of Scenedesmus sp. showed greater selectivity for obtaining fat components of 71.47% and 94.99%, respectively. The results showed that depending on the solvent/method used to quantify the lipids, the selectivity for obtaining the grease fraction, fundamental for conversion into biofuels, varies and the total lipid content may be overestimated.

Photobioreactor of Microalgas for CO_(2) Biofixation

Microalgae are unicellular organisms capable of photosynthesis, turning sunlight and carbon dioxide (CO2) into rich biomass. Precisely because of this definition, in recent years various sectors have been targeting their ability to reduce CO2 emissions and the capacity of simultaneously synthesize biomass which can be later used to produce bio-fuels. Besides being considered fast-growth microorganisms, microalgae have a diverse biochemical composition with similar characteristics to traditional biomass. In this context, the present work aimed to evaluate the biofixation of CO2 by the microalgae Monoraphidium sp., cultivated in a closed-window type photobioreactor, as well as characterization of microalgal biomass produced in relation to the total lipid content (TL), lipids converted into biodiesel (LCB), carbohydrates and proteins. The results achieved showed that the best result was obtained after 24 h of cultivation, where for each gram of biomass produced approximately 1.2 g of CO2 were consumed. In the growth phase the average biomass productivity in the Janela photobioreactor was 58 mg&middot;L-1&middot;day-1 concluding that microalgae culture systems could be coupled to the chimneys of large industries emitters CO2 using this gas, resulting from combustion processes, in the process of photosynthesis. The biomass Monoraphidium sp. produced had a content of lipids converted into biodiesel of approximately 8.36% ± 2.69%, carbohydrates 32% ± 3.37% and proteins 34.26% ± 0.41%.

Cultivation of Microalgae <i>Monoraphidium</i>sp., in the Plant Pilot the Grand Valle Bio Energy, for Biodiesel Production

At present, Brazil imports approximately 11 billion liters/year of diesel. With the interruption of the works in the new Petrobras refineries, the projection is that by 2025 this volume will increase to 24.2 billion liters of diesel/year. In this sense, the biodiesel factory Grand Valle Bio Energy Ltda., located in the state of Rio de Janeiro, in conjunction with the FAPERJ makes some investments in technology development for the cultivation and use of microalgae as an alternative raw material in the production of biodiesel. Based on arguments previously said, this work presents the results of the microalgae cultivation Monoraphidium sp. in photobioreactors the pilot plant of the company. The installation with an area of 120 m2 is included with 2 open photobioreactors of type falling film (20 m × 1 m), with a cascade of 18mm and capacity of 4000 L. The lineage cultivated is selected from previous ecophysiological studies that are identified as promising for biodiesel production by having a high potential for the production of lipids. This lineage is maintained at collection of the stock of cultures Laboratory of Green Technologies of the School of Chemistry/ UFRJ. The cultivation was performed in means ASM-1 (Gorham et al., 1964), initial pH 8.0, with aeration and circulation average of 8 hours a day during 19 days. The culture was started with an inoculum of 1 × 107 cel/ml. The lipid production was determined in two phases of growth: on day 4 (exponential phase) and 15 day (stationary phase). For the determination and quantification of lipid content, two different methods were assessed for a sample of biomass, submitted to the same processes the separation and drying. The results showed the methodology of Bligh & Dyer with modifications as the most efficient in extracting lipids. The total lipid content of the biomass Monoraphidium sp. was 30.58%. The growth rate varied between 0.74 ± 0.01 and 0.68 ± 0.02.

Biodiesel Production Based in Microalgae: A Biorefinery Approach

It is of great knowledge nowadays that the use of fossil fuels is responsible for the emission of gases that intensify the greenhouse effect, which threatens the survival of the humankind. The gravity of this fact could be mitigated through the indirect use of solar energy for fuels derived from vegetable that can be planted and cultivated by the world of renewable and non-polisher. Microalgae play an important role in this regard, as they have promising characteristics as potential raw material for the production of biofuels, able to absorb large amounts of CO2. Chlorophyll organisms convert these simple substances in the atmosphere, absorbing sunlight into chemical energy stored, that is, compounds with high energy, biomass can also be used to obtain biocompounds human nutritional supplement and food animal, however, have been found an important number of difficulties to economically viable production like high cost of production of dry biomass and oil extraction. Here, we review the main approaches of biorefinery concept appearing as an alternative to achieve economic viability of the production of bio-diesel based on microalgae. The major points are the following: 1) use of re-residual water, 2) marketing of Carbon Credits, and 3) development of co-products resulting from high value added.

Primary Separation of Antioxidants (Unsaponifiables) the Wet Biomass Microalgae <i>Chlamydomonas</i>sp. and Production of the Biodiesel

This work studies the saponification which directs the wet biomass of algae Chlamydomonas sp. like a previous stage to production of biodiesel. This stage allows the obtainment of fatty acids to produce biodiesel, instead of the gross lipid fraction. In addition of the fatty acids, utilizing the same process one can also obtain the fraction unsaponifiable, these are soluble in apolar solvents and contain mainly carotenoids that can take action as antioxidants and photoprotectors, as they reduce the oxidation of unsaturated fatty acids. The saponification direct and extraction of fatty acids from biomass is faster and reduces the time and cost of operation. The separation of unsaponifiable matter from the biomass humid of microalgae Chlamydomonas sp., was held according to the method AOCS (Ca 6a-40), using extraction Liquid-liquid with hexane as solvent. Subsequently, phase hydroalcoholic or from soap, containing fatty acids, was acidified by addition of H2SO4 and the fatty acids were recovered by the addition of hexane. After acidulation of the soap, necessary for obtaining of the fatty acids was performed the stage of esterification for obtaining of biodiesel. The operating conditions were: molar ratio fatty acid:methanol (1:10), as catalyst 8% H2SO4 calculated in relation to the mass of fatty acid, 200℃ and reaction time of 90 minutes. The content of methyl esters was 96.8% determined by gas chromatography according to standard EN14103. The quality of biodiesel produced from wet biomass of Chlamydomonas sp. is according to the specification established by standard EN 14214 and RANP No. 14. For the identification of the composition the unsaponifiable fraction was used the method of High Performance Liquid Chromatography (HPLC). The composition of the material unsaponifiable found was of: Carotenoids total (0.76%);Lutein (0.45%);Zeaxanthin (0.07%);α-carotene (0.05%);β-carotene (0.11%);13 cisβ-carotene (0.05%) and 9-cisβ-carotene (0.03%).