31/08/2011

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PROGRAM OF SELECTION OF NEW SPECIES AND STRAINS OF MICROALGAES WITH HIGH POTENTIAL FOR LIPID PRODUCTION.

Supported by PSE Microalgas (Proyectos Singulares Estratégicos)PSE-440000-2009-016

Laura Carmona, Adelina de la Jara, Karen Freijanes, Patricia Assunção, Eduardo Portillo and Héctor Mendoza.aDepartamento de Biotecnología. División de Investigación y Desarrollo Tecnológico. Instituto Tecnológico de Canarias (ITC). Pozo Izquierdo, 35119 Sta. Lucía, Gran Canaria.

*Contacts: lcarmona@itccanarias.org, depbio@itccanarias.org

INTRODUCTION

RESULTS & DISCUSION

MATERIAL & METHODS

Of the 30.000 different species of microalgae, only 10% have been characterized andcultivated. The selection of new strains for biodiesel production or for other purposes isdetermined by the difficulty of characterization and selection (difficulty in sample processing,scalability, growth rate versus lipogenesis, etc.)

In this project we develop a simple program (based on microculture and flow cytometry) forthe selection of microalgae with high potential for lipids production. With this method weselected five strains, from 35 new field isolates and culture collections strains, that stood outfor its high lipid production.

SCALABILITY:Relations between photobioreactor results and those obtained on culture chamber for the productivity and

relative lipid content.

Very significant correlation P = 0.99

The Techniques used:Microcultures: It can reproduce with some degree of reliability the growing conditions of the major massive cultures, without theconstraints imposed by the need to handle large volumes.Multiparametric analysis by flow cytometry Flow cytometry is as a sensitive, specific and rapid technique that can be used toanalyse at the same time a large number of cellular parameters (size, complexity, vitality, relative content of lipids, etc.)Conventional analytic: Cell growth, Dry Weight, Total Carbon and Nitrogen.

Parameters for characterizing:Cell growth rate: Fundamental parameter not only of the potential productivity of the microalgae cultures, but also of the degreeof adaptation of species and strains to the systems and production conditions.Cytometric indicator of dry weight per cell: The cytometric SSC parameter in combination with the rate of cell growth allows arapid estimation of biomass production.Indicator of potential productivity: Estimated by flow cytometry and automated cell counting. (SSC+FSC*Maximum density)/daysRelative lipid content: Cells stained with Nile Red and analyzed by flow cytometry.Ratio Carbon/Nitrogen: Indicator of the composition and physiological state of microalgae.Lipid extracts: The ability of extracting lipids from microalgae is so important as microalgae ability for producing them; moreoveroptimizes resources and reduces costs.

•These results demonstrate the full feasibility of developing a program of "screening" by microcultures and flowcytometry, making it possible to set cytometric markers for the selection of strains with high potential for growthand/or production of biodiesel. This is a fast and cheap screening method for the study of a large number ofstrains.•The increased scale of production systems does not change the outcome of the selection of strains and there is asignificant correlation between the different growing methods: microcultures, photobioreactors and raceways.This result is of great interest since the microcultures management is easier and faster. Furthermore, themicrocultures method do not have the environmental variations of the great outdoor culture systems, allowing acomparison between strains without the constraint of limiting parameters as temperature or light intensity.•The ability to extract lipids, is a decisive factor for a better selection of strains.

Finally, the data allowed the selection of the five following strains among the 35 studied for the biodieselproduction on a large scale:

•ITC 17(00)-S-0209 (Picochlorum sp.): It has a high growth rate, high lipid content and relativepotential productivity.•ITC 04(00)-D.0209 (Chlorella sp.): It has also a high growth rate and productivity potential, as wellas their high fat content . it is easy to extract the lipids.•ITC-ISO-01 (Isochrysis Galbana): It has a high relative content in lipids, high potential productivityand it is easy to extract the lipids.•ITC05(00)-D.0209 / ITC10(00)-D.0209 (Micractinium sp.): It has a high growth rate, relative contentof lipids and potential productivity.• ITC03(00)-D.0209 (Scenedesmus sp.): It has a high growth rate, relative lipid and potentialproductivity.

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Potential productivity values estimated by cytometric and automatedcell counting. (SSC+FSC*Maximum density)/days)

Correlation between dry weight and cell size (flow cytometry.)

Correlation between cell growth rate and potential productivity

Relative lipid content given by flow cytometry and Nile Red

Extraction efficiency =fatty acids extracted (μg/ml) over the number of extractions performed

Relation between potential productivity and the efficiency of extraction

Cytometric Production

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