Chlorella Protothecoides

The novelty of this work is the estimation of the fuel properties of biodiesel, a comparison study with conventional sources of biodiesel commonly used as feedstock, and an investigation for meeting the requirements of the standard specifications for this fuel produced by six strains of microalgae (three cyanobacteria, two green algae and one diatom), cultivated photosynthetically in a bubble column photobioreactor. Lipid productivity and biofuel quality were the criteria for species selection. RESULTS: Chlorella vulgaris was found to be the best strain for use as a feedstock for biodiesel production and for this specie, a carbon dioxide sequestration rate of 17.8 mg L -1 min -1 , a biomass productivity of 20.1 mg L -1 h -1 , a lipid content of 27.0% and a lipid productivity of 5.3 mg L -1 h -1 were obtained. Qualitative analysis of the fatty acid methyl esters demonstrates the predominance of saturated ( .5%) and monounsaturated (41.9%) fatty acids. The quality properties of the biodiesel were an ester content of 99.8%, a cetane number of 56.7; an iodine value of 65.0 g I 2 100 g -1 ; a degree of unsaturation of 74.1% and a cold filter plugging point of 4.5 • C. CONCLUSION: The results indicate that among the fuel properties tested, the microalgal biodiesel complies with the US Standard (ASTM 6751), European Standard (EN 14214), Brazilian National Petroleum Agency (ANP 255) and Australian Standard for biodiesel.

Identificando la situación actual del biodiésel
en el contexto nacional e internacional, se
pretende evaluar mediante un modelo de
negocio verde la viabilidad de crear una
empresa de producción y comercialización
de biodiésel a partir de la microalga Chlorella en Colombia.
Por medio de matrices de decisión de alternativas y validando algunos procesos a nivel experimental, se analizaron
y eligieron las características técnicas/operativas requeridas
para el proceso de producción. Se desarrollaron estudios de
mercado de intencionalidad exploratorio, organizacional y
financiero, proyectando a GreenFuels & Consultores Colombia
como una empresa que producirá y comercializará biodiésel a
partir de Chlorella, para atender las distribuidoras mayoristas,
que requieren mezclas diésel-biodiésel de calidad y cumplir
con sus metas de producción, aumentando paralelamente sus externalidades positivas al ambiente y la sociedad. Por lo tanto,
GreenFuels & Consultores Colombia como modelo de negocio
verde, es un proyecto viable en términos técnicos, validado en
el mercado, con una propuesta de valor clara e innovadora y
financieramente rentable.

To confront energy shortage, global warming and climate changes, biofuels derived from biomass have received increasing attention from the industry, academia and governments. Of the potential sources of biofuels a most promising one is the simple photosynthetic microalgae, which can be grown in open ponds, photobioreactors and fermenters. The advantages to produce biofuels from microalgae include easy adaption to environmental conditions, high photosynthesis efficiency, high lipid content and noncompetition for farmlands. Nonetheless, the real hallmark of microalgae is the fact that these microscopic organisms can provide the biomass feedstock for the flexible production of several different types of renewable and sustainable biofuels such as biodiesel, bioethanol, biogas, biohydrogen among others via thermochemical and biochemical conversion processes. Amazingly, from a sustainability perspective the integrated algal biofuels production, where biodiesel, bioethanol and biogas are continuously produced from one biomass source, can evidently lead to an increase in the energetic productivity of the microalgal biomass, thus improving the economics of this algal biorefinery approach. Developments in several areas, such as genetic and metabolic engineering, are expected to further improve the costeffectiveness of the biofuels from microalgae in an environmentally sustainable manner.

Bioflocculant from Cobetia marina was used for flotation of Chlorella vulgaris. The efficiency of bioflocculant with Ca 2+ for flotation of C. vulgaris was > 90%. Effects of temperature, pH and metal ions on flotation efficiency were investigated. The bioflocculant is stable at wide ranges of pH and temperature.

Harvesting and extracting lipids from the microalgal biomass are the most expensive processes in biodiesel production. This study focuses on reducing the lipid extraction cost using ozone-rich microbubbles technique. The lipid extraction of Dunaliella salina slurry with methanol (1:2 v/v) was performed in a 0.2 L bioreactor at room temperature with direct ozonation (8 mg L À 1). When the temperature was increased (60 ̊C) and smaller bubbles were introduced during extraction, the concentration of products increased significantly to around 156%, 88.9% and 150% for 6,10,14-trimethylpentadecan-2-one, palmitic acid and stearic acid, respectively. The energy usage for extracting D. salina lipid with ozone has been estimated to be around 2.16 MJ kg À 1 dry algae (36% energy) which is a small fraction of the energy that is used in the production of biodiesel, unlike centrifugation and solvent extraction methods, which consume more than 90% of the energy.

BACKGROUND: The novelty of this work is the estimation of the fuel properties of biodiesel, a comparison study with conventional sources of biodiesel commonly used as feedstock, and an investigation for meeting the requirements of the standard specifications for this fuel produced by six strains of microalgae (three cyanobacteria, two green algae and one diatom), cultivated photosynthetically in a bubble column photobioreactor. Lipid productivity and biofuel quality were the criteria for species selection. RESULTS: Chlorella vulgaris was found to be the best strain for use as a feedstock for biodiesel production and for this specie, a carbon dioxide sequestration rate of 17.8 mg L −1 min −1 , a biomass productivity of 20.1 mg L −1 h −1 , a lipid content of 27.0% and a lipid productivity of 5.3 mg L −1 h −1 were obtained. Qualitative analysis of the fatty acid methyl esters demonstrates the predominance of saturated (43.5%) and monounsaturated (41.9%) fatty acids. The quality properties of the biodiesel were an ester content of 99.8%, a cetane number of 56.7; an iodine value of 65.0 g I 2 100 g −1 ; a degree of unsaturation of 74.1% and a cold filter plugging point of 4.5 • C. CONCLUSION: The results indicate that among the fuel properties tested, the microalgal biodiesel complies with the US Standard (ASTM 6751), European Standard (EN 14214), Brazilian National Petroleum Agency (ANP 255) and Australian Standard for biodiesel.

The concept of a biorefinery improves the economic efficiency of a biofuel production process from microalgae by recovering high value added compounds. Lutein is a carotenoid currently extracted from petals of Tagetes erecta with an established market in poultry and in human nutritional supplements. For the very first time, an extended study on the lipid and lutein production over three Chlorella species as well as cell disruption methods was performed. Chlorella vulgaris, Chlorella zofingiensis and Chlorella protothecoides were grown in an indoor vertical alveolar panel photobioreactor with continuous illumination, and two cell disruption methods were assessed at a laboratory scale: glass bead vortexing and ball mill grinding. For C. vulgaris, C. zofingiensis and C. protothecoides the intracellular lutein content was measured as: 3.86, 4.38 and 3.59 mg g −1 respectively. Lipid contents vary slightly among microalgae with a value close to 9% w/w. Biomass and lutein productivities were found to be higher for C. vulgaris (0.131 gL −1 d −1 , 0.51 mg L −1 d −1) and for C. zofingiensis (0.122 gL −1 d −1 , 0.53 mg L −1 d −1) compared to C. protothecoides (0.103 gL −1 d −1 , 0.37 mg L −1 d −1). C. vulgaris 1803 and C. zofingiensis B 32 were found to be promising organisms for simultaneous production of lutein and lipids. Although all the microalgae under study belong to the same genus, a species-specific response was observed for each of the cell grinding methods tested.

Chlorella protothecoides, a lipid-producing microalga, was grown heterotrophically and autotrophically in separate reactors, the off-gases exiting the former being used to aerate the latter. Autotrophic biomass productivity with the two-reactor association, 0.0249 g L −1 h −1 , was 2.2-fold the value obtained in a control autotrophic culture, aerated with ambient air. Fatty acid productivity was 1.7-fold the control value. C. protothecoides heterotrophic biomass productivity was 0.229 g L −1 h −1. This biomass' fatty acid content was 34.5% (w/w) with a profile suitable for biodiesel production, according to European Standards. The carbon dioxide fixed by the autotrophic biomass was 45 mg CO 2 L −1 h −1 in the symbiotic arrangement, 2.1 times the control reactor value. The avoided CO 2 atmospheric emission represented 30% of the CO 2 produced in the heterotrophic stage, while the released O 2 represented 49% of the oxygen demand in that stage. Thus, an increased efficiency in the glucose carbon source use and a higher environmental sustainability were achieved in microalgal biodiesel production using the proposed assembly.

Harvesting and extracting lipids from the microalgal biomass are the most expensive processes in biodiesel production. This study focuses on reducing the lipid extraction cost using ozone-rich microbubbles technique. The lipid extraction of Dunaliella salina slurry with methanol (1:2 v/v) was performed in a 0.2 L bioreactor at room temperature with direct ozonation (8 mg L À 1). When the temperature was increased (60 ̊C) and smaller bubbles were introduced during extraction, the concentration of products increased significantly to around 156%, 88.9% and 150% for 6,10,14-trimethylpentadecan-2-one, palmitic acid and stearic acid, respectively. The energy usage for extracting D. salina lipid with ozone has been estimated to be around 2.16 MJ kg À 1 dry algae (36% energy) which is a small fraction of the energy that is used in the production of biodiesel, unlike centrifugation and solvent extraction methods, which consume more than 90% of the energy.

Microalgal biodiesel is a promising alternative fuel because of the following: 1) its high productivity in comparison with crops oil 2) it does not affect food production, and 3) its lower emissions and potential to reduce environmental pollution. The aims of this work are firstly to produce and extract lipid from a fresh water microalgae Chlorella vulgaris using iron as a stress treatment to achieve high lipid content. Secondly, the physical and chemical properties of Chlorella vulgaris and Chlorella protothecoides oil will be compared with diesel and biodiesel from other sources.

The present study introduced an integrated method for the production of biodiesel from microalgal oil. Heterotrophic growth of Chlorella protothecoides resulted in the accumulation of high lipid content (55%) in cells. Large amount of microalgal oil was efficiently extracted from these heterotrophic cells by using n-hexane. Biodiesel comparable to conventional diesel was obtained from heterotrophic microalgal oil by acidic transesterification. The best process combination was 100% catalyst quantity (based on oil weight) with 56:1 molar ratio of methanol to oil at temperature of 30 °C, which reduced product specific gravity from an initial value of 0.912 to a final value of 0.8637 in about 4 h of reaction time. The results suggested that the new process, which combined bioen-gineering and transesterification, was a feasible and effective method for the production of high quality biodiesel from microalgal oil.

The freshwater microalga Chlorella vulgaris was grown heterotrophically in fed-batch 50-600-L fermenters at 36°C, on aerated and mixed nutrient solution with urea as a nitrogen and glucose as a carbon and energy source. Cell density increased from the initial value 6.25 to 117.18 g DW L −1 in 32 h in the fermenter 50 L at a mean growth rate 3.52 g DW L −1 h −1 . The DW increase in the fermenter 200 L was from 7.25 to 94.82 g DW L −1 in 26.5 h at a mean growth rate 3.37 g DW L −1 h −1 . Mean specific growth rate μ was about 0.1 h −1 in the both fermenters, if nutrients and oxygen were adequately supplied. The DW increase in the fermenter 600 L was from 0.8 to 81.6 g DW L −1 in 66.5 h at a mean growth rate 1.22 g DW L −1 h −1 and μ=0.07 h −1 . A limitation of the cell growth rate in 600 L fermenter caused by a low dissolved oxygen concentration above cell densities higher than 10 g DW L −1 ) occurred. Specific growth rate decreased approximately linearly with increasing glucose concentration (25-80 g glucose L −1 ) at the beginning of cultivation and decreased with the time of cultivation. The cell yield was 0.55-0.69 g DW (g glucose) −1 . The content of proteins, β-carotene, and chlorophylls in the cells steadily increased and starch content decreased, by keeping aerated and mixed culture another 12 h in fermenter after the cell growth was stopped due to glucose deficiency.

Microalgal biodiesel is a promising alternative fuel because of the following: 1) its high productivity in comparison with crops oil 2) it does not affect food production, and 3) its lower emissions and potential to reduce environmental pollution. The aims of this work are firstly to produce and extract lipid from a fresh water microalgae Chlorella vulgaris using iron as a stress treatment to achieve high lipid content. Secondly, the physical and chemical properties of Chlorella vulgaris and Chlorella protothecoides oil will be compared with diesel and biodiesel from other sources.

The aim of the study was to obtain high quality biodiesel production from a microalga Chlorella protothecoids through the technology of transesterification. The technique of metabolic controlling through heterotrophic growth of C. protothecoides was applied, and the heterotrophic C. protothecoides contained the crude lipid content of 55.2%. To increase the biomass and reduce the cost of alga, corn powder hydrolysate instead of glucose was used as organic carbon source in heterotrophic culture medium in fermenters. The result showed that cell density significantly increased under the heterotrophic condition, and the highest cell concentration reached 15.5 g L −1 . Large amount of microalgal oil was efficiently extracted from the heterotrophic cells by using n-hexane, and then transmuted into biodiesel by acidic transesterification. The biodiesel was characterized by a high heating value of 41 MJ kg −1 , a density of 0.864 kg L −1 , and a viscosity of 5.2 × 10 −4 Pa s (at 40 • C). The method has great potential in the industrial production of liquid fuel from microalga.