Optimization of production of biofuels from macro algae

OPTIMIZATION OF PRODUCTION OF BIOFUELS FROM MACRO-ALGAE Production of bioethanol using different macroalgae

What we are looking for:  To define the optimal technological combinations for the pre-treatment of macroalgae, such as diluted acidnanowires.  To optimize the polysaccharide conversion step to fermentable sugars using recombinant enzymes.  To promote the exchange of ideas, science and technology between Chile and Finland.

SECOND YEAR MAIN RESULTS 1. In the research objectives Pretreatment with Ionic Liquids: The pretreatment using different ionic liquids (DBU-MEA-SO2s, [TMGH+][EtCO2-] and [HDBU+][5OF-]), confirmed to be potential for treating algae, especially Ulva rigida, not only for dissolving carbohydrates (up to 91 wt.% of carbohydrates was dissolved at the optimal temperature) in order to obtain sugars to be fermented into ethanol, but also to obtain byproducts under a biorefinery concept. One of the most important variables of the process is the temperature: the next challenges are to obtain the dissolution reaction kinetic, in order to optimize the process and improve the carbohydrate dissolution yield.

Photocatalytic pretreatment of algal biomass: Photocatalytic Pretreatment with different types of nanoparticles and nanowires as catalysts (Pure anatase nanoparticles, nanowires and those decorated with platinum and palladium nanoparticles) have been tested. The results of determinations of types and amounts of released carbohydrates in solid and liquid phases (Galactose, Xylose, Glucose, Glucuronic acid, Mannitol, Mannose, Galacturonic acid and Rhamnose (Ulva Rigida), and Fucose and Alginate (M.pyrifera)) indicate that the photocatalytic process itself has little effect on the degradation of Algae; however, control experiments are yet to be run to make conclusive statements.

Identification of new bacterial alginate lyase enzymes for M. pyrifera degradation: More than ten gens of endolytic alginate lyases and eight oligoalginate lyases have been identified. Nine of the alginate lyases were cloned into E.coli and in three of them activity was detected. Enzymes showing best activities will be used in the stages of M. pyrifera enzymatic saccharification using alginate lyases, Enzymatic saccharification of M. pyrifera using alginate lyases: Considering that the first polysaccharide component in M. pyrifera is

alginate, the optimal operating conditions for the enzymatic saccharification of M. pyrifera using alginate lyases from Sigma and oligoalginate lyases from BAL company were determined. The level of released uronic acid from M. pyrifera was 193.7 ± 10.6 mg uronic acid/g algae.

Enzymatic saccharification of M. pyrifera using cellulases and βglucosidase: Considering that the second polysaccharide component in M. pyrifera is cellulose, the optimal operating conditions for the enzymatic saccharification of M. pyrifera using commercial cellulases and βglucosidase were determined. The level of released glucose from M. pyrifera was 55.74 ± 0.05 mg glucose/g algae.

Separate Hydrolysis and Fermentation (SHF) of alginate with E. coli and Simultaneous Saccharification and Fermentation (SSF) of alginate with E.coli. Considering that the first polysaccharide component in the M. pyrifera is alginate, the SHF and SSF processes were compared to obtain bioethanol using a modified E.coli strain consuming uronic acid. The results show that the production of ethanol with the SSF process gave better results when compared to the SHF process.

Microorganisms that saccharify and ferment uronic acid with better yields continue to be searched.

Simultaneous Saccharification and Fermentation (SSF) of cellulose with S. cerevisia. Considering that the second polysaccharide component in the M. pyrifera is cellulose, a SSF process was carried out to obtain bioethanol using a S. cerevisiae strain. Conversion levels are 28.9 and 19.2 wt-% of theoretical yield of ethanol production when diluted sulphuric acid/autoclaved and DI water/autoclaved are used as pretreatment, respectively.

Extracting polyphenols from M. pyrifera . Different protocols have been tested for polyphenol extraction from M. pyrifera. Marine oxygen enzymes which may help in this extraction process are currently being searched, and three of these showing activities of interest have been found.

2. Conjoint activities a) Characterization of polysaccharides and polyphenols of Ulva rigida and Macrocystis pyrifera b) Pretreatment of alga biomass with different kinds of Ionic Liquids (ILs) c) Simultaneous Saccharification and Fermentation (SSF) of cellulose with S. cerevisiae

3. In training of young researchers a) Promotion of exchange of ideas and technology between Chile and Finland through the visit of Chilean researcher to Finland last April b) Exchange of one Postdoctoral researcher to Finland for two months c) Exchange of one doctoral student to Chile for workshop

4. Education a) Three undergraduate students b) One Doctoral student c) Two Postdoctoral positions

5. Dissemination a) Two manuscripts have been submitted to Algal Research, and there are other three in preparation b) Eight presentations at international congresses and workshop; and two Chilean congress c) Organization of two workshops with international guests. One in Santiago, Chile and another in Oulu, Finland d) Participation in four outreach activities

RESEARCHERS INVOLVED 1. María Elena Lienqueo, Universidad de Chile, Departamento de Ingeniería Química y Biotecnología, Chile 2. Jyri-Pekka Mikkola, Åbo Akademi University, Faculty of Technology, Department of Chemical Engineering, Process Chemistry, Centre, Finland 3. Juan Asenjo, Universidad de Chile, Departamento de Ingeniería Química y Biotecnología, Chile 4. Oriana Salazar, Universidad de Chile, Departamento de Ingeniería Química y Biotecnología, Chile 5. Päivi Mäki-Arvela, Åbo Akademi University, Faculty of Technology, Department of Chemical Engineering, Process Chemistry, Centre, Finland 6. Krisztian Kordas, University of Oulu, Microelectronics and Materials Physics Laboratories, Finland 7. Allison Leyton, Universidad de Chile, Departamento de Ingeniería Química y Biotecnología, Chile 8. Cristina Ravanal, Universidad de Chile, Departamento de Ingeniería Química y Biotecnología, Chile 9. Javier Gimpel, Universidad de Chile, Departamento de Ingeniería Química y Biotecnología, Chile 10. Sari Hyvärinen, Åbo Akademi University, Faculty of Technology, Department of Chemical Engineering, Process Chemistry, Centre, Finland 11. Ricardo Pezoa, Åbo Akademi University, Faculty of Technology, Department of Chemical Engineering, Process Chemistry, Centre, Finland 12. Aron Domboravi, University of Oulu, Microelectronics and Materials Physics Laboratories, Finland 13. Melinda Mohl, University of Oulu, Microelectronics and Materials Physics Laboratories, Finland

CONCLUSION It is considered that the proposed objectives for the second year of the project have been satisfactorily completed.

The Chilean group has been focused on the fermentation of the polysaccharides from algal biomass and extraction of Macrocystis pyrifera polyphenols. However both processes could be improved.

On the other hand, for the Finnish researchers, the focus of the research at Turku, Finland, has been on the characterization of algal biomass, Ionic Liquid pretreatment and sugar characterization after different pretreatments (using ionic liquid, photocatalytic material and acid agents).

In the case of ionic liquid pretreatments the temperature of the process should be improved.

In Oulu, at the University of Oulu, a new technique had been implemented for the pretreatment of algal biomass using photocatalytic materials; however, further control experiments are to be run to make conclusive statements.

Finally, it has been confirmed that the tested methodology has potential for treatment of algae, not only for dissolving carbohydrates in order to obtain sugars to be fermented into ethanol, but also to obtain byproducts, such as polyphenols, under a biorefinery concept.

Contacto: MarĂ­a Elena Lienqueo (mlienque@ing.uchile.cl)