The potential of optimized process design to advance LCA performance of algae production systems
Boxtel, A.J.B. van; Perez-Lopez, P. ; Breitmayer, E. ; Slegers, P.M. - \ 2015
Applied Energy 154 (2015). - ISSN 0306-2619 - p. 1122 - 1127.
life-cycle assessment - biodiesel production - microalgae
Environmental impact is an essential aspect for the introduction of algae production systems. As information of large scale algae production is hardly available, process simulation is the only way to evaluate environmental sustainability in an early phase of process design. Simulation results allow the evaluation of production and design scenarios, and reveal the potential to improve the Life Cycle Performance of algae production systems. In this work, we discuss how choices in the process design of algae production systems (cultivation, biorefinery and the supply chain) advance LCA-results
Cell disruption for microalgae biorefineries
Günerken, E. ; Hondt, E. d'; Eppink, M.H.M. ; Garcia-Gonzalez, L. ; Elst, K. ; Wijffels, R.H. - \ 2015
Biotechnology Advances 33 (2015)2. - ISSN 0734-9750 - p. 243 - 260.
microwave-assisted extraction - fluidized-bed adsorption - electric-field treatment - synechocystis pcc 6803 - life-cycle assessment - chlorella-vulgaris - lipid extraction - microbial-cells - saccharomyces-cerevisiae - biodiesel production
Microalgae are a potential source for various valuable chemicals for commercial applications ranging from nutraceuticals to fuels. Objective in a biorefinery is to utilize biomass ingredients efficiently similarly to petroleum refineries in which oil is fractionated in fuels and a variety of products with higher value. Downstream processes in microalgae biorefineries consist of different steps whereof cell disruption is the most crucial part. To maintain the functionality of algae biochemicals during cell disruption while obtaining high disruption yields is an important challenge. Despite this need, studies on mild disruption of microalgae cells are limited. This review article focuses on the evaluation of conventional and emerging cell disruption technologies, and a comparison thereof with respect to their potential for the future microalgae biorefineries. The discussed techniques are bead milling, high pressure homogenization, high speed homogenization, ultrasonication, microwave treatment, pulsed electric field treatment, non-mechanical cell disruption and some emerging technologies.
Selecting microalgae with high lipid productivity and photosynthetic activity under nitrogen starvation
Benvenuti, G. ; Bosma, R. ; Cuaresma Franco, M. ; Janssen, M.G.J. ; Barbosa, M.J. ; Wijffels, R.H. - \ 2015
Journal of Applied Phycology 27 (2015)4. - ISSN 0921-8971 - p. 1425 - 1431.
neochloris-oleoabundans - parietochloris-incisa - marine-phytoplankton - biodiesel production - nutrient stress - fatty-acids - light - accumulation - efficiency - biofuels
An economically feasible microalgal lipid industry heavily relies on the selection of suitable strains. Because microalgae lipid content increases under a range of adverse conditions (e.g. nutrient deprivation, high light intensity), photosynthetic activity is usually strongly reduced. As a consequence, lipid productivity rapidly declines overtime, after reaching a maximum within the first days of cultivation. The microalgae Chlorella vulgaris, Chlorococcum littorale, Nannochloropsis oculata, Nannochloropsis sp., Neochloris oleoabundans, Stichococcus bacillaris and Tetraselmis suecica were compared on fatty acid content and productivity, and also on photosynthetic activity under nitrogen (N) starvation. Cultures in N-replete conditions were used as reference. Photosystem II (PSII) maximumefficiency was followed during the experiment, as proxy for the change in photosynthetic activity of the cells. Strains with a high capacity for both lipid accumulation as well as high photosynthetic activity under N starvation exhibited a high lipid productivity over time. Among the tested strains, Nannochloropsis sp. showed highest fatty acid content (45%w/w) and productivity (238 mg L-1 day-1) aswell as PSII maximum efficiency, demonstrating to be the most suitable strain, of those tested, for lipid production. This study highlights that for microalgae, maintaining a high photosynthetic efficiency during stress is the key to maintain high fatty acid productivities overtime and should be considered when selecting strains for microalgal lipid production.
Biorefinery methods for separation of protein and oil fractions from rubber seed kernel
Widyarani, R. ; Ratnaningsih, E. ; Sanders, J.P.M. ; Bruins, M.E. - \ 2014
Industrial Crops and Products 62 (2014). - ISSN 0926-6690 - p. 323 - 332.
aqueous enzymatic extraction - supercritical carbon-dioxide - hevea-brasiliensis seeds - biodiesel production - functional-properties - alpha-lactalbumin - nutritive-value - amino-acids - products - recovery
Biorefinery of rubber seeds can generate additional income for farmers, who already grow rubber trees for latex production. The aim of this study was to find the best method for protein and oil production from rubber seed kernel, with focus on protein recovery. Different pre-treatments and oil separation methods were tested, and alkaline conditions were used to extract protein. Next to processes with subsequent oil and protein recovery, a one-step combined oil and protein extraction was tested. Our study showed that oil separation is not necessary to obtain high protein recovery, however most of the extracted oil is present as an emulsion. The origin of the seeds and their treatment on the plantation before processing were most important for high oil and protein recoveries, and in all cases tested had more influence on recoveries than its subsequent method of processing. Pressing the rubber seed kernel to separate the oil fraction followed by protein extraction from the press cake gives the highest protein recovery with satisfactory recovery for oil.
A model-based combinatorial optimisation approach for energy-efficient processing of microalgae
Slegers, P.M. ; Koetzier, B.J. ; Fasaei, F. ; Wijffels, R.H. ; Straten, G. van; Boxtel, A.J.B. van - \ 2014
Algal Research 5 (2014). - ISSN 2211-9264 - p. 140 - 157.
response-surface methodology - life-cycle assessment - biodiesel production - algal biomass - process integration - transesterification - oil - flocculation - biorefinery - extraction
The analyses of algae biorefinery performance are commonly based on fixed performance data for each processing step. In this work, we demonstrate a model-based combinatorial approach to derive the design-specific upstream energy consumption and biodiesel yield in the production of biodiesel from microalgae. Process models based on mass and energy balances and conversion relationships are presented for several possible process units in the algae processing train. They allow incorporating the effects of throughput capacity and process conditions, which is not possible in the data-based approach. Therefore, the effect of choices in the design on the overall performance can be quantified. The process models are organised in a superstructure to evaluate all combinations of routings. First, this is done for selected fixed design conditions, which is followed by optimisation of the process conditions for each route by maximising the net energy ratio (NER), based on upstream energy consumption and biodiesel yield. A scenario based on current energy production and state-of-the art techniques for algae processing is considered. The optimised process conditions yield NER values which are up to about 30% higher than those for fixed process conditions. In addition, the approach allows a quantitative bottleneck analysis for each process route. The model-based approach proves to be a versatile tool to guide the design of efficient microalgae processing systems.
Scenario evaluation of open pond microalgae production
Slegers, P.M. ; Lösing, M.B. ; Wijffels, R.H. ; Straten, G. van; Boxtel, A.J.B. van - \ 2013
Algal Research 2 (2013)4. - ISSN 2211-9264 - p. 358 - 368.
life-cycle assessment - phaeodactylum-tricornutum - growth-rate - tubular photobioreactors - thalassiosira-pseudonana - biodiesel production - mass-culture - temperature - model - light
To evaluate microalgae production in large scale open ponds under different climatologic conditions, a model-based framework is used to study the effect of light conditions, water temperature and reactor design on trends in algae productivity. Scenario analyses have been done for two algae species using measured weather data of the Netherlands and Algeria. The effects of temperature control, photo-inhibition and using monthly or yearly fixed biomass concentrations are estimated by a sensitivity analysis. The calculation-based results show that climate conditions such as solar irradiation and temperature dynamics play an important role in open raceway ponds. In moderate climate zones low and high temperatures over a season suppress growth. At high latitudes this effect is important as light levels vary much during the day and between seasons. Optimal biomass concentrations in ponds depend on location, pond depth and algae species. Pond design, location and algae species interact and productivity cannot be based solely on general or assumed efficiencies. It is essential to select algae species that have a suitable growth rate, light absorption coefficient and the ability to grow over a broad temperature range. The presented approach gives a framework to validate specific cultivation systems
Carbon and nitrogen mass balance during flue gas treatment with Dunaliella salina
Harter, T. ; Bossier, P. ; Verreth, J.A.J. ; Bodé, S. ; Ha, D. van der; Debeer, A.E. ; Boon, N. ; Boeckx, P. ; Vyverman, W. ; Nevejan, N. - \ 2013
Journal of Applied Phycology 25 (2013)2. - ISSN 0921-8971 - p. 359 - 368.
life-cycle assessment - nitric-oxide - tubular photobioreactor - denitrifying bacteria - biodiesel production - organic-carbon - biological co2 - green-algae - microalgae - dioxide
The biotreatment of flue gases with algae cultures is a promising option to sequestrate CO2, yet the emission of other greenhouse gases (GHG) from the cultures can hamper their environmental benefit. Quantitative data on the sequestration potential for CO2 and NO x in relation to the direct production of CH4 and N2O are urgently required. The present study assessed the flows of carbon (C) and nitrogen (N) through cultures of the green alga Dunaliella salina, supplied with biodiesel flue gas, by means of mass balancing. D. salina was grown in artificially lighted, field- (42-L bubble column reactor) and laboratory-scale cultures (23 °C, pH 7.5). In the bubble column reactor, algae grew with an average specific growth rate of 0.237 day-1 under flue gas supplementation (6.3 % (v/v) CO2, 1.2 ppmv NO x ), and CO2 was retained to 39 % in the system. The specific sequestration rate for CO2 was low, with 0.13 g CO2 L-1 day-1. Cultures emitted up to 13.03 µg CH4 L-1 day-1 and 4261 µg N2O L-1 day-1. The moderate retention of NO x -N was outweighed by emissions of N2O-N, and total N in the system decreased by 15.48 % during the 9-day trial. Results suggest that GHG production was mainly the outcome of anaerobic microbial processes and their emission was lower in pre-sterilized cultures. Under the tested conditions, up to six times more CO2 equivalents were emitted during flue gas treatment. Therefore, the direct GHG emissions of algae culture systems, intended for flue gas treatment (i.e. open ponds) need to be reviewed critically.
Growth and lipid production of Umbelopsis isabellina on a solid substrate - Mechanistic modeling and validation
Meeuwse, P. ; Klok, A.J. ; Haemers, S. ; Tramper, J. ; Rinzema, A. - \ 2012
Process Biochemistry 47 (2012)8. - ISSN 1359-5113 - p. 1228 - 1242.
state fermentation system - gamma-linolenic acid - oleaginous fungi - diffusion-coefficients - biodiesel production - aspergillus-oryzae - chemostat model - oxygen - glucose - accumulation
Microbial lipids are an interesting feedstock for biodiesel. Their production from agricultural waste streams by fungi cultivated in solid-state fermentation may be attractive, but the yield of this process is still quite low. In this article, a mechanistic model is presented that describes growth, lipid production and lipid turnover in a culture of Umbelopsis isabellina on ¿-carrageenan plates containing the monomers glucose and alanine as C-source and N-source, respectively, and improves the understanding of the complex solid-state system. The model includes reaction kinetics and diffusion of glucose, alanine and oxygen. It is validated empirically and describes the different phases of the culture very well: exponential growth, linear growth because of oxygen limitation, accumulation of lipids and carbohydrates after local N-depletion and turnover of lipids after local C-depletion. Extending the model with an unidentified extracellular product improved the fit of the model to the data. The model shows that oxygen limitation is extremely important in solid-state cultures using monomers, and explains the difference in production rate with submerged cultures. However, the results also show that the specific lipid production rate in solid-state cultures is much lower than in submerged cultures, which results in a low lipid yield
Modeling growth, lipid accumulation and lipid turnover in submerged batch cultures of Umbelopsis isabellina
Meeuwse, P. ; Akbari, P. ; Tramper, J. ; Rinzema, A. - \ 2012
Bioprocess and Biosystems Engineering 35 (2012)4. - ISSN 1615-7591 - p. 591 - 603.
solid-state fermentation - oleaginous microorganisms - mortierella-isabellina - microbial lipids - cunninghamella-echinulata - mucor-circinelloides - biodiesel production - mathematical-model - chemostat model - fungi
The production of lipids by oleaginous yeast and fungi becomes more important because these lipids can be used for biodiesel production. To understand the process of lipid production better, we developed a model for growth, lipid production and lipid turnover in submerged batch fermentation. This model describes three subsequent phases: exponential growth when both a C-source and an N-source are available, carbohydrate and lipid production when the N-source is exhausted and turnover of accumulated lipids when the C-source is exhausted. The model was validated with submerged batch cultures of the fungus Umbelopsis isabellina (formerly known as Mortierella isabellina) with two different initial C/N-ratios. Comparison with chemostat cultures with the same strain showed a significant difference in lipid production: in batch cultures, the initial specific lipid production rate was almost four times higher than in chemostat cultures but it decreased exponentially in time, while the maximum specific lipid production rate in chemostat cultures was independent of residence time. This indicates that different mechanisms for lipid production are active in batch and chemostat cultures. The model could also describe data for submerged batch cultures from literature well.
Two-phase systems: Potential for in situ extraction of microalgal products
Kleinegris, D.M.M. ; Janssen, M.G.J. ; Brandenburg, W.A. ; Wijffels, R.H. - \ 2011
Biotechnology Advances 29 (2011)5. - ISSN 0734-9750 - p. 502 - 507.
intracellularly stored products - beta-carotene production - botryococcus-braunii - chlamydomonas-reinhardtii - dunaliella biotechnology - saccharomyces-cerevisiae - hydrocarbon recovery - biodiesel production - organic-solvents - l-phenylalanine
Algae are currently used for production of niche products and are becoming increasingly interesting for the production of bulk commodities, such as biodiesel. For the production of these goods to become economically feasible, production costs will have to be lowered by one order of magnitude. The application of two-phase systems could be used to lower production costs. These systems circumvent the costly step of cell harvesting, whilst the product is extracted and prepared for downstream processing. The mechanism of extraction is a fundamental aspect of the practical question whether two-phase systems can be applied for in situ extraction, viz, simultaneous growth, product formation and extraction, or as a separate downstream processing step. Three possible mechanisms are discussed; 1) product excretion 2) cell permeabilization, and 3) cell death. It was shown that in the case of product excretion, the application of two-phase systems for in situ extraction can be very valuable. With permeabilization and cell death, in situ extraction is not ideal, but the application of two-phase systems as downstream extraction steps can be part of a well-designed biorefinery process. In this way, processing costs can be decreased while the product is mildly and selectively extracted. Thus far none of the algal strains used in two-phase systems have been shown to excrete their product; the output has always been the result of cell death. Two-phase systems can be a good approach as a downstream processing step for these species. For future applications of two-phase in situ extraction in algal production processes, either new species that show product excretion should be discovered, or existing species should be modified to induce product excretion.
Modeling lipid accumulation in oleaginous fungi in chemostat cultures: I. Development and validation of a chemostat model for Umbelopsis isabellina
Meeuwse, P. ; Tramper, J. ; Rinzema, A. - \ 2011
Bioprocess and Biosystems Engineering 34 (2011)8. - ISSN 1615-7591 - p. 939 - 949.
solid-state fermentation - fatty-acid-composition - gamma-linolenic acid - mortierella-isabellina - mucor-circinelloides - biodiesel production - malic enzyme - carbon - growth - oils
Lipid-accumulating fungi may be able to produce biodiesel precursors from agricultural wastes. As a first step in understanding and evaluating their potential, a mathematical model was developed to describe growth, lipid accumulation and substrate consumption of the oleaginous fungus Umbelopsis isabellina (also known as Mortierella isabellina) in submerged chemostat cultures. Key points of the model are: (1) if the C-source supply rate is limited, maintenance has a higher priority than growth, which has a higher priority than lipid production; (2) the maximum specific lipid production rate of the fungus is independent of the actual specific growth rate. Model parameters were obtained from chemostat cultures of U. isabellina grown on mineral media with glucose and NH4+. The model describes the results of chemostat cultures well for D > 0.04 h-1, but it has not been validated for lower dilution rates because of practical problems with the filamentous fungus. Further validation using literature data for oleaginous yeasts is described in part II of this paper. Our model shows that not only the C/N-ratio of the feed, but also the dilution rate highly influences the lipid yield in chemostat cultures.
Design scenarios for flat panel photobioreactors
Slegers, P.M. ; Wijffels, R.H. ; Straten, G. van; Boxtel, A.J.B. van - \ 2011
Applied Energy 88 (2011)10. - ISSN 0306-2619 - p. 3342 - 3353.
life-cycle assessment - phaeodactylum-tricornutum - marine-phytoplankton - biodiesel production - microalgae - biofuels - light - model
Evaluation of the potential of algae production for biofuel and other products at various locations throughout the world requires assessment of algae productivity under varying light conditions and different reactor layouts. A model was developed to predict algae biomass production in flat panel photobioreactors using the interaction between light and algae growth for the algae species Phaeodactylum tricornutum and Thalassiosira pseudonana. The effect of location, variable sunlight and reactor layout on biomass production in single standing and parallel positioned flat panels was considered. Three latitudes were studied representing the Netherlands, France and Algeria. In single standing reactors the highest yearly biomass production is achieved in Algeria. During the year biomass production fluctuates the most in the Netherlands, while it is almost constant in Algeria. Several combinations of path lengths and biomass concentrations can result in the same optimal biomass production. The productivity in parallel place flat panels is strongly influenced by shading and diffuse light penetration between the panels. Panel orientation has a large effect on productivity and at higher latitudes the difference between north–south and east–west orientation may go up to 50%.
Microalgae bulk growth model with application to industrial scale systems
Quinn, J. ; Winter, L. de; Bradley, T. - \ 2011
Bioresource Technology 102 (2011)8. - ISSN 0960-8524 - p. 5083 - 5092.
nannochloropsis sp - phytoplankton growth - biodiesel production - carbon-sources - algae growth - temperature - light - optimization - productivity - acclimation
The scalability of microalgae growth systems is a primary research topic in anticipation of the commercialization of microalgae-based biofuels. To date, there is little published data on the productivity of microalgae in growth systems that are scalable to commercially viable footprints. To inform the development of more detailed assessments of industrial-scale microalgae biofuel processes, this paper presents the construction and validation of a model of microalgae biomass and lipid accumulation in an outdoor, industrial-scale photobioreactor. The model incorporates a time-resolved simulation of microalgae growth and lipid accumulation based on solar irradiation, species specific characteristics, and photobioreactor geometry. The model is validated with 9 weeks of growth data from an industrially-scaled outdoor photobioreactor. Discussion focuses on the sensitivity of the model input parameters, a comparison of predicted microalgae productivity to the literature, and an analysis of the implications of this more detailed growth model on microalgae biofuels lifecycle assessment studies
Selective preparation of terminal alkenes from aliphatic carboxylic acids by a palladium-catalysed decarbonylation-eliminiation reaction
Notre, J.E.L. le; Scott, E.L. ; Franssen, M.C.R. ; Sanders, J.P.M. - \ 2010
Tetrahedron Letters 51 (2010)29. - ISSN 0040-4039 - p. 3712 - 3715.
biodiesel production - stearic-acid - fatty-acids - deoxygenation - oil - decarboxylation - telomerization - conversion - butadiene - chemicals
Trialkylamines were used as additives in the decarbonylation–elimination reaction catalysed by the combination of palladium(II) chloride and DPE-Phos. Aliphatic carboxylic acids were transformed at relatively low temperature into terminal alkenes in high yield and high selectivity, without the need for distillation, thereby avoiding isomerisation
Resource use efficiency and environmental performance of nine major biofuel crops, processed by first-generation conversion techniques
Vries, S.C. de; Ven, G.W.J. van de; Ittersum, M.K. van; Giller, K.E. - \ 2010
Biomass and Bioenergy 34 (2010)5. - ISSN 0961-9534 - p. 588 - 601.
chain energy analysis - biodiesel production - sweet sorghum - fuel ethanol - soil - thailand - cassava - systems - impact - sugar
We compared the production–ecological sustainability of biofuel production from several major crops that are also commonly used for production of food or feed, based on current production practices in major production areas. The set of nine sustainability indicators focused on resource use efficiency, soil quality, net energy production and greenhouse gas emissions, disregarding socio-economic or biodiversity aspects and land use change. Based on these nine production–ecological indicators and attributing equal importance to each indicator, biofuel produced from oil palm (South East Asia), sugarcane (Brazil) and sweet sorghum (China) appeared most sustainable: these crops make the most efficient use of land, water, nitrogen and energy resources, while pesticide applications are relatively low in relation to the net energy produced. Provided there is no land use change, greenhouse gas emissions of these three biofuels are substantially reduced compared with fossil fuels. Oil palm was most sustainable with respect to the maintenance of soil quality. Maize (USA) and wheat (Northwest Europe) as feedstock for ethanol perform poorly for nearly all indicators. Sugar beet (Northwest Europe), cassava (Thailand), rapeseed (Northwest Europe) and soybean (USA) take an intermediate position.
Aquatic worms grown on biosolids: Biomass composition and potential applications
Elissen, H.J.H. ; Mulder, W.J. ; Hendrickx, T.L.G. ; Elbersen, H.W. ; Beelen, M.J.C. ; Temmink, B.G. ; Buisman, C.J.N. - \ 2010
Bioresource Technology 101 (2010)2. - ISSN 0960-8524 - p. 804 - 811.
lumbriculus-variegatus oligochaeta - biodiesel production - sewage-sludge - earthworms - bioaccumulation - toxicity - sediment - cadmium - lipids - diet
The increasing production of biological waste sludge from wastewater treatment plants is a problem, because stricter legislation inhibits the use of traditional disposal methods. The use of the aquatic worm Lumbriculus variegatus can minimise sludge production. Because the worms can feed and grow on this waste sludge, valuable compounds that are present in the sludge can be recovered by the worms. This paper describes a systematic approach for finding possible applications of the produced biomass. The worm biomass mainly consists of protein and smaller fractions of fat, sugar and ash. It also contains low concentrations of heavy metals. The potential produced amount is relatively small, compared to other waste streams, and is produced decentrally. Therefore, the most promising applications are specific components of the biomass, for example specific amino acids or fatty acids. However, until the process is optimized and there is a stable supply of worms, the focus should be on simple applications, later on followed by specific applications, depending on the market demand. Worm biomass grown on clean sludges has a broader application potential, for example as consumption fish feed.