Turbidostat operation of outdoor pilot-scale photobioreactors
J.H. de Vree, Rouke Bosma, Rick Wieggers, Snezana Gegic, Marcel Janssen, Maria Barbosa, René Wijffels
Algal research, volume 18, September 2016, 198-208
The effect of biomass concentration on areal productivity and photosynthetic efficiency of Nannochloropsis sp. CCAP211/78 was studied in three outdoor pilot-scale photobioreactors: an open raceway pond (OPR), a horizontal tubular (HT) photobioreactor and a vertically stacked horizontal tubular (VT) photobioreactor. The reactors were operated continuously as turbidostat at different biomass concentrations. For all systems highest areal productivities were obtained on days with a high light intensity, while the highest photosynthetic efficiencies were obtained on days with a low light intensity. Ground areal biomass concentration exceeding 51 g m− 2 had a negative effect on the areal productivity and photosynthetic efficiency. No significant effect of biomass concentration on the productivity was found for the HT at ground areal biomass concentration lower than 51 g m− 2. Also for the VT, no significant effect of biomass concentration was found with the exception of the highest biomass concentration of 2.0 g L− 1 (68 g m− 2) resulting in decreased productivity. For the open raceway pond the highest biomass concentration (0.5 g L− 1 or 94 g m− 2) resulted in significantly lower areal productivity, compared to the lower biomass concentration (0.25 g L 47 g m− 2). Highest areal productivities were obtained for OPR and VT, most likely due to more efficient light interception. In this study we observed that night biomass loss was coupled to net growth. At lower biomass concentrations and concomitant higher growth rates the specific biomass loss rate was higher. Microalgal specific light absorption coefficient was correlated to biomass concentration; higher biomass concentrations resulted in higher specific absorption coefficients, resulting in a steeper light gradient in the microalgal cultures.
Towards industrial products from microalgae
Jesús Ruiz, Giuseppe Olivieri, Jeroen de Vree, Rouke Bosma, Philippe Willems, J. Hans Reith, Michel H.M. Eppink, Dorinde M.M. Kleinegris, René H. Wijffels, Maria J. Barbosa
Energy and Environmental science
Microalgae show an enormous potential as sustainable feedstock for numerous bioproducts. The current work analyzes the feasibility of business cases for different markets of products from microalgae. We perform a techno-economic evaluation of the whole process chain including cultivation, biorefinery and market exploitation for a 100 hectares facility in six locations. Our projections show a current cost per unit of dry biomass of 3.4 €·kg -1 for microalgae cultivation in Spain (excluding biorefining products), with an expected reduction to 0.5 €·kg-1 in ten years. A sensitivity analysis reveals the roadmap to achieve this. Production of high-value products (e.g. pigments) would be currently profitable, with a net present value of 657 M€ in 15 years. Markets aimed at food and chemical commodities require further cost reductions for cost competitiveness, reachable in the next decade.
Comparison of four outdoor pilot-scale photobioreactors
Jeroen H. de Vree, Rouke Bosma, Marcel G.H. Janssen, Maria J. Barbosa, René H. Wijffels
Biotechnology for Biofuels, Volume 20158:215, 2015
Microalgae are a potential source of sustainable commodities of fuels, chemicals and food and feed additives. The current high production costs, as a result of the low areal productivities, limit the application of microalgae in industry. A first step is determining how the different production system designs relate to each other under identical climate conditions. The productivity and photosynthetic efficiency of Nannochloropsis sp. CCAP 211/78 cultivated in four different outdoor continuously operated pilot-scale photobioreactors under the same climatological conditions were compared. The optimal dilution rate was determined for each photobioreactor by operation of the different photobioreactors at different dilution rates.
In vertical photobioreactors, higher areal productivities and photosynthetic efficiencies, 19-24 g m(-2) day(-1) and 2.4-4.2 %, respectively, were found in comparison to the horizontal systems; 12-15 g m(-2) day(-1) and 1.5-1.8 %. The higher ground areal productivity in the vertical systems could be explained by light dilution in combination with a higher light capture. In the raceway pond low productivities were obtained, due to the long optical path in this system. Areal productivities in all systems increased with increasing photon flux densities up to a photon flux density of 30 mol m(-2) day(-1). Photosynthetic efficiencies remained constant in all systems with increasing photon flux densities. The highest photosynthetic efficiencies obtained were; 4.2 % for the vertical tubular photobioreactor, 3.8 % for the flat panel reactor, 1.8 % for the horizontal tubular reactor, and 1.5 % for the open raceway pond.
Vertical photobioreactors resulted in higher areal productivities than horizontal photobioreactors because of the lower incident photon flux densities on the reactor surface. The flat panel photobioreactor resulted, among the vertical photobioreactors studied, in the highest average photosynthetic efficiency, areal and volumetric productivities due to the short optical path. Photobioreactor light interception should be further optimized to maximize ground areal productivity and photosynthetic efficiency.
Design and construction of the microalgal pilot facility AlgaePARC
Rouke Bosma, Jeroen H. de Vree, Petronella M. Slegers, Marcel G.J. Janssen, René H. Wijffels, Maria J. Barbosa
Algal Research, Volume 6, 2015, Pages 160 – 169.
Microalgae gained much interest from industry as promising sustainable feedstock for the production of food, feed, bulk chemicals, and biofuels. Pilot scale research on microalgae is needed to bridge the gap between laboratory scale research and commercial applications. The AlgaePARC (Algae Production And Research Center) pilot facility was constructed to bridge this gap. The objective of this pilot center is to compare and improve photobioreactors and operational strategies under outdoor conditions. The pilot plant facility consists of four production systems (raceway pond, horizontal tubular reactor, vertically stacked tubular reactor and flat panels) and allows comparison of performance of these systems under identical climatological conditions. This paper describes the development of this pilot facility, decisions made during the building process and discusses the production systems including technical specifications, measurements and supporting facilities.
Analysis of Fatty Acid Content and Composition in Microalgae
Guido Breuer, Wendy A.C. Evers, Jeroen H. de Vree, Dorinde M.M. Kleinegris, Dirk E. Martens, René H. Wijffels, and Packo P. Lamers
Journal of Visualized Experiments, Volume 80, 2013, 50628
One of the main challenges for the successful production and use of microalgae for biodiesel production is to obtain a satisfactory level of fatty acid methyl esters (FAME). The aims of this study are to identify the best method of lipid extraction and provide high FAME levels and to evaluate their fatty acid profiles. Six lipid extraction methodologies in three microalgae species were tested in comparison with the direct transesterification (DT) of microalgal biomass method. The choice of extraction method affected both the oily extract yield and the FAME composition of the microalgae and consequently may affect the properties of biodiesel. The efficiency of different lipid extraction methods is affected by the solvent polarity, which extracts different target compounds from lipid matrix. Dichloromethane/methanol extraction and Folch extraction produced the largest oil extract yields, but extraction with hexane/ethanol resulted in the best ester profile and levels. Performing DT reduces the volume of extractor solvent, the time and cost of FA composition analysis, as well as, presents less steps for fatty acid quantification. DT provided biomass FAME levels of 50.2, 636.4, and 258.2 mg.g−1 in Nannochlorophisis oculata, Chaetoceros muelleri, and Chlorella sp., respectively. On the basis of an analysis of the fatty acids profiles of different species, C. muelleri is a promising microalga for biodiesel production. Depending on the extraction method, Chlorella sp. and N. oculata can be considered as an alternative in obtaining arachidonic (Aa) and eicosapentaenoic (EPA) acids.