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Koller M.,University of Graz | Muhr A.,University of Graz | Muhr A.,Polymer Competence Center Leoben | Braunegg G.,ARENA Arbeitsgemeinschaft fur Ressourcenschonende und Nachhaltige Technologien
Algal Research

As major part of the phytoplankton, microalgae are pivotal for the global food chain. Their exceptional capacity for CO2-fixation illustrates their indispensable significance to sustain earth's ecosystems. Further, they play a still underestimated role in eliminating contaminants from various environments. In addition to ecological benefit, many microalgal species exhibit high nutritional value and, at the same time, generate valued bio-products: Pigments, lipids, bioactive compounds, certain polysaccharides, bio-hydrogen and even biopolyesters with plastic-like properties have the potential for successful market penetration.Three substantial pigment groups, namely chlorophylls, carotenoids, and phycobilins, are essential for light harvesting and CO2 fixation. Those pigments will most likely undergo quick commercial success in "functional food", cosmetics, aquaculture, pharmaceuticals, or food technology.Due to often high contents of polyunsaturated fatty acids essential for human metabolism, microalgal oils can be commercialized as health food and in the pharmaceutical and therapeutic field, creating much higher value than by converting them to biofuel.Finally, algal biomass remaining as residue after product recovery can be used as forage, biogas feedstock or biofertilizer. This utilization is needed for balancing the material- and energy cycles of the entire process. Thus, technology platforms following the principles of bio-refineries shall be established to enable the design of sustainable and economically feasible production of marketable microalgal products. © 2014 Elsevier B.V. Source

Koller M.,University of Graz | Salerno A.,University of Graz | Tuffner P.,Joanneum Research | Koinigg M.,Joanneum Research | And 6 more authors.
Journal of Cleaner Production

The review highlights the correlation between removal of various eco-toxins by micro algae and the production of high-value products thereof. It appraises established and novel strategies for micro algal cultivation, downstream processing methods for product recovery, and recent progress in algal generation of the green energy carriers biogas and biohydrogen micro algae. The suitability of selected micro algal species for various final products, and the potential of different strains for abating environmental problems are discussed. Due to the fact that low cell densities and moderate growth rates are known as the major obstacles towards a broad market penetration of micro algal products, the article shows how high cell densities and reasonable volumetric productivities can be obtained. Here, the article deals with the improvements of process design and nutrient supply regimes that are needed to achieve these goals. As demonstrated by an integrated case study, mixotrophic cultivation results in increased biomass concentration in a first cultivation step for some micro algal strains like Nannochloropsis oculata. In a second step, the fresh active algal biomass accumulates desired products via CO 2 fixation, e.g. from industrial effluent gases, as the sole carbon source. This can be realized by a novel, two-stage, continuously operated closed photo-bioreactor system. After cell harvest and optimized product recovery, the value-added conversion of residual algal biomass for generation of green energy carriers, e.g. in biogas plants, constitutes another focal point of the ongoing research. © 2012 Elsevier Ltd. All rights reserved. Source

Koller M.,University of Graz | Sandholzer D.,University of Graz | Salerno A.,University of Graz | Braunegg G.,ARENA Arbeitsgemeinschaft fur Ressourcenschonende und Nachhaltige Technologien | And 2 more authors.
Resources, Conservation and Recycling

Life cycle assessment (LCA) has turned into a powerful tool to critically and straightforward assess the holistic impact of bio-based plastics and other bio-based products. In order to assure at the same time ecological soundness and to support the economical success of a bioproduct, an early assessment already in the stage of product development is needed. This strategy helps to identify and subsequently to avoid ecological "hot spots". Assessment by using the sustainable process index (SPI), a member of the ecological footprint family, is considered as an especially viable strategy to realize this goal. The software SPIonExcel was developed to make the assessment methodology easily applicable and operator-friendly. During the process of development for archaebacterial production of poly(hydroxyalkanoate) (PHA) biopolyesters from the industrial surplus material whey, a SPI assessment was accomplished to optimize the process in terms of ecological sustainability. As the major outcome, the resulting ecological footprint was comparable with that of competing fossil plastics. Additionally, optimization potentials to further increase the ecological competitiveness were highlighted and quantified. In addition, the developed PHA production process was compared with production of whey powder as the competing, conventional application of surplus whey. Also in this case, the novel PHA production process was superior according to the SPI calculations. © 2013 Elsevier B.V. Source

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