Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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De toekomst van hout in de biobased economy
Annevelink, E. ; Harmsen, P.F.H. ; Spijker, J.H. - \ 2018
Vakblad Natuur Bos Landschap 15 (2018)141. - ISSN 1572-7610 - p. 7 - 11.
biobased economy - hout - biobrandstoffen - biomassa - hernieuwbare energie - materialen uit biologische grondstoffen - cellulose - lignine - vezels - wood - biofuels - biomass - renewable energy - biobased materials - lignin - fibres
De laatste jaren is de biobased economy sterk gegroeid door allerlei activiteiten, variërend van fundamenteel onderzoek naar nieuwe biobased toepassingen, tot het op commerciële schaal vervaardigen van biobased producten. Welke kansen biedt dit voor hout en houtige biomassa en wat zijn de verwachte effecten op de houtmarkt?
Overheidsmaatregelen biokerosine : mogelijkheden om de vraag naar biokerosine te stimuleren en de effecten op de luchtvaart en de economie
Faber, Jasper ; Smeets, E.M.W. - \ 2017
Delft : CE Delft - 112
biobrandstoffen - biobased economy - kerosine - overheidsbeleid - stimulatie - subsidies - emissiereductie - luchttransport - biofuels - kerosene - government policy - stimulation - emission reduction - air transport
De maatregel met het grootste potentieel om CO2-emissies van de luchtvaart te verminderen is het gebruik van brandstoffen met lage emissies over de levenscyclus, zoals bijvoorbeeld geavanceerde biobrandstoffen gemaakt van residuen uit de bos- en landbouw. Om de luchtvaart te laten bijdragen aan de afname van de wereldwijde emissies is het dus wenselijk een groter aandeel alternatieve duurzame brandstoffen in de luchtvaart in te zetten. Vanwege het prijsverschil tussen fossiele kerosine en biokerosine is hier overheidsbeleid voor nodig. Het doel van deze studie is het beantwoorden van de volgende twee centrale onderzoeksvragen: 1. Met welke beleidsmaatregelen kan de Nederlandse Rijksoverheid de vraag naar en productie van biokerosine laten toenemen? 2. Wat zijn de directe en indirecte effecten van de beleidsmaatregelen?
Socio-economic assessment of Algae-based PUFA production
Voort, Marcel van der; Spruijt, Joanneke ; Potters, Jorieke ; Wolf, Pieter de; Elissen, Hellen - \ 2017
Göttingen : PUFAChain - 84
bioenergy - biobased economy - biofuels - biomass - algae - fatty acids - bio-energie - biobrandstoffen - biomassa - algen - vetzuren
Biobased materialen, circulaire economie en natuurlijk kapitaal
Overbeek, M.M.M. ; Smeets, E.M.W. ; Verhoog, A.D. - \ 2017
Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (WOt-technical report 109) - 37
biomassa - biobased economy - materialen uit biologische grondstoffen - bioplastics - hernieuwbare energie - duurzaamheid (sustainability) - biobrandstoffen - recycling - chemie op basis van biologische grondstoffen - biomass - biobased materials - renewable energy - sustainability - biofuels - biobased chemistry
This preliminary study investigates the amount of biomass that would be needed in the Netherlands to replace the fossil raw materials used in the manufacture of plastics and how this transition to biobased plastics can be achieved. It is based on desk research and calculations of the area of agricultural land that would be needed to produce sufficient biobased material to meet Dutch demand for biobased plastics. In addition, interviews were held with experts on the institutional obstacles to such a transition. Far too little agricultural land is available in the Netherlands to produce the required amount of biomass needed to replace fossil plastics. Research with the aim of increasing the contribution made by biobased materials to the circular economy should focus on assessing the options for producing sustainable raw materials and on a comprehensive assessment of the sustainable use of biomass in various applications.
Circular food chains and cascading of biomass in metropolitan regions : Vision on metropolitan biorefinery concepts in relation to resource-efficient cities
Annevelink, E. ; Gogh, J.B. ; Groot, J.J. - \ 2017
Wageningen : Wageningen Food & Biobased Research (Wageningen Food & Biobased Research report 1790) - ISBN 9789463437424 - 18
biomass - bioenergy - residual streams - refining - biofuels - biobased economy - biogas - biomassa - bio-energie - reststromen - raffineren - biobrandstoffen
Expectations are that 80 percent of the global population will reside in urban areas by the year 2050. As urbanisation levels increase so do ecological footprint sizes in these areas, as it is in the cities that income levels are higher, and where higher levels of disposable incomes exist. Whereas the circular economy is gaining ground as a concept for increasing sustainability by the efficient use of available materials and resources, urban areas are often recognised as attractive starting points for making the transition towards a circular economy. The paper “Circular food chains and cascading of biomass in metropolitan regions” contains the description of a vision on how biorefinery concepts in current and future metropoles may contribute to the increased efficiency in the use of resources for biomass production. As such this vision forms the interpretation of the principles of the circular economy within the context of biomass value chains and within the geographic boundaries of a metropolitan region. This is also referred to as the circular metropolitan system. With this paper researchers from Wageningen Food & Biobased Research intend to contribute to a scientific basis for increasing resource use efficiency in metropolitan regions through developing appropriate and sustainable biorefinery concepts.
Innovatieve technologie in beheer en oogst van houtige biomassa : eindrapportage
Raa, Rik te; Pfau, S. ; Clerkx, A.P.P.M. ; Massop, Hans ; Hissink, H.J. - \ 2017
BTG Biomass Technology Group - 57 p.
bio-energie - biobased economy - biobrandstoffen - hout - biomassa productie - bosbeheer - bioenergy - biofuels - wood - biomass production - forest administration
Opiniestuk sustainable development goals : transities realiseren met duurzaam bodem - en landgebruik
Mol, G. ; Cleen, M. de; Molenaar, Co ; Keesstra, S. ; Visser, S. ; Okx, J. - \ 2017
Wageningen : Wageningen University and Research - 7
duurzame energie - biobased economy - biobrandstoffen - biogas - overheidsbeleid - klimaat - bio-energie - reststromen - hernieuwbare energie - energiebeleid - sustainable energy - biofuels - government policy - climate - bioenergy - residual streams - renewable energy - energy policy
In 2015 hebben de Verenigde Naties de Duurzame Ontwikkelingsdoelen – beter bekend als de Sustainable Development Goals of kortweg SDGs – aangenomen als de weg waarlangs ze de meest urgente problemen op het gebied van armoede, honger, maar ook onderwijs, economie, en milieu en klimaat wil aanpakken. De ambities, geformuleerd in de 17 SDGs, zijn verstrekkend en hoog. In verschillende Nederlandse beleidsdocumenten1234567 wordt daarom aangegeven dat hiervoor serieuze maatschappelijke transities nodig zijn zoals op het gebied van energie en klimaat, voedselvoorziening en circulaire economie, mobiliteit en leefbare steden. Voor veel van deze transities is duurzaam gebruik en beheer van bodem, water en land een essentieel onderdeel. Dit opiniestuk heeft als doel de rol van duurzaam bodem- en landgebruik te benadrukken en de urgentie ervan agenderen voor de maatschappelijke transities waar Nederland voor staat. En laten zien dat de maatschappelijke opgaven te complex zijn voor een sectorale aanpak. Integrale benadering en goede samenwerking tussen alle stakeholders zijn nodig om te komen tot duurzame oplossingen. Het is raadzaam hier voortvarend werk van te maken; de bodem is een traag systeem, dus 2030 – het jaar waarin de SDGs moeten zijn gerealiseerd – is al morgen.
Biodigestion at the Neighbourhood Level : from community participation to waste separation
Hiemstra, J. ; Lie, R. ; Rietveld, M. - \ 2017
Urban Agriculture Magazine (2017)32. - ISSN 1571-6244 - p. 49 - 51.
bio-energie - biobrandstoffen - biobased economy - reststromen - projecten - co-vergisting - digestaat - hernieuwbare energie - energiebronnen - organisch afval - recycling - bioenergy - biofuels - residual streams - projects - co-fermentation - digestate - renewable energy - energy sources - organic wastes
Urban Agriculture magazine • number 32 • September 2017 49 www.ruaf.org High energy bills and litter on the streets caused a group of residents of the Wildeman neighbourhood in the district of Osdorp in Amsterdam to act. Expecting no solution from the municipality, they decided to take care of it themselves and tackled these two problems with one solution: using the technology of biodigestion to produce energy from municipal food waste - a perfect example of the urban food-waste-energy nexus.
Groene Cirkels : Resultaatrapportage
Steingröver, E.G. ; Vos, C.C. - \ 2017
Wageningen : Groene Cirkels - 15 p.
bio-energie - biobrandstoffen - biobased economy - duurzame energie - indicatoren - biomassa - bioenergy - biofuels - sustainable energy - indicators - biomass
Met de resultaatmeting wil Groene Cirkels inzichtelijk maken wat er bereikt is ten aanzien van het bereiken van onze doelen en ambities. Met deze informatie wil Groene Cirkels effectief sturen op het behalen van de ambities en inzicht geven in de bijdragen en resultaten van de diverse thema-activiteiten en Groene Cirkels
The SEEA EEA carbon account for the Netherlands
Lof, Marjolein ; Schenau, Sjoerd ; Jong, Rixt de; Remme, Roy ; Graveland, Cor ; Hein, Lars - \ 2017
The Hague : Statistics Netherlands - 64
carbon dioxide - netherlands - carbon - economics - environment - biofuels - bioenergy - biogas - emission - kooldioxide - nederland - koolstof - economie - milieu - biobrandstoffen - bio-energie - emissie
The carbon account provides a comprehensive overview of all relevant carbon stocks and flows. The carbon account for the Netherlands was developed within the scope of the ‘System of Environmental Economic Accounts – Experimen tal Ecosystem Accounting’ (SEEA EEA) project for the Netherlands (Natuurlijk Kapitaalrekeningen Nederland: NKR_NL), which is currently c arried out jointly by Statistics Netherlands and Wageningen University. Funding and support was provided by the Ministries of Economic Affairs and Infrastructure and the Environment. Within the NKR_NL project, a number of accounts are currently under devel opment. The carbon account is described in detail in this report.
Sustainable woodfuel for food security : A smart choice: green, renewable and affordable
Sooyeon, Laura Jln ; Schure, J.M. ; Ingram, V.J. ; Yoo, Byoung Il ; Reeb, Dominique ; Xia, Zuzhang ; Perlis, Andrea ; Nordberg, Mats ; Campbell, Jeffrey ; Muller, Eva - \ 2017
FAO - ISBN 9789251099629 - 35 p.
biobased economy - biofuels - bioenergy - wood - biomass - heat - biobrandstoffen - bio-energie - hout - biomassa - warmte
With food insecurity, climate change and deforestation and forest degradation remaining key global issues, this paper highlights the role of sustainable woodfuel in improving food security. Food insecurity and a high dependence on woodfuel as a primary cooking fuel are characteristics common to vulnerable groups of people in developing regions of the world.With adequate policy and legal frameworks in place, woodfuel production and harvesting can be sustainable and a main source of green energy. Moreover, the widespread availability of woodfuel, and the enormous market for it, presents opportunities for employment and for sustainable value chains, providing further rationale for promoting this source of energy. This paper explains how sustainable woodfuel is closely linked to food security and provides insights in how the linkages could be strengthened at all stages of woodfuel production, trade and use.
Measurements of transcripts, proteome and metabolite profiles
Peters, Sander - \ 2017
Fuel4Me - 7
biobased economy - biobrandstoffen - algen - algenteelt - oliën - biofuels - algae - algae culture - oils
The work described for this deliverable was carried out by DLO-PRI, in collaboration with WU, and aim ed to understanding lipid production in Phaeodactylum tricornutum . By means of transcriptome, proteome and metabolome analyses we aimed to provide insight into the one step lipid production performed by partner WU. Cultivation conditions were chosen to steer lipid profile towards most suitable composition for biofuel production.
Photosynthetic efficiency in microalgal lipid production
Remmers, Ilse M. - \ 2017
University. Promotor(en): Rene Wijffels, co-promotor(en): Packo Lamers. - Wageningen : Wageningen University - ISBN 9789463434607 - 200
algae - biofuels - light - triacylglycerols - lipids - metabolism - algae culture - cultural methods - algen - biobrandstoffen - licht - triacylglycerolen - lipiden - metabolisme - algenteelt - cultuurmethoden

Microalgae can contain large amounts of lipids which make them a promising feedstock for sustainable production of food, feed, fuels and chemicals. Various studies, including pilot-scale, have been performed and the knowledge on microalgal processes has advanced quickly. Unfortunately, current production costs for cultivation are still too high for bulk lipid production from microalgae.

One of the major causes for the high costs of bulk lipid production is the reduced solar-to-lipid conversion efficiency. Current research, however, does not provide sufficient insight to identify optimization targets. Therefore, in this thesis we have studied the lipid production in microalgae in depth.

Different TAG-accumulation strategies were investigated from a process engineering and metabolic point of view. The combination of all findings were used in the general discussion to thoroughly evaluate the microalgal lipid accumulation strategies. Current phototrophic microalgal lipid yields are still 10 times lower than the theoretical maximum. There is, however, still an enormous potential for further improvements. Future research should focus on (genetically) improved strains and advanced cultivation strategies, including adaptation to fluctuating outdoor weather conditions.

This thesis was performed within the EU FP7 FUEL4ME project under grand agreement No 308938. Objective of this program is to develop a sustainable and scalable process for biofuels from microalgae and to valorize the by-products.

Exploring opportunities for rural livelihoods and food security in Central Mozambique
Leonardo, Wilson José - \ 2017
University. Promotor(en): Ken Giller, co-promotor(en): Gerrie van de Ven; Henk Udo. - Wageningen : Wageningen University - ISBN 9789463431651 - 183
agricultural production systems - food security - crop production - livelihoods - small farms - biofuels - farming systems - models - intensification - mozambique - agrarische productiesystemen - voedselzekerheid - gewasproductie - middelen van bestaan - kleine landbouwbedrijven - biobrandstoffen - bedrijfssystemen - modellen - intensivering

Growing awareness of widespread hunger and poverty in many countries in the SSA is spurring a focus on productivity increase in smallholder farming systems. The rationale is that with current production systems many SSA countries are not keeping pace with population growth and changing of peoples’ lifestyles. To respond to this challenge the Government of Mozambique developed its Strategic Plan for Agricultural Development (PEDSA) aiming to improve agricultural productivity of the majority of smallholder farmers who depend on agriculture for their livelihoods. Smallholder farmers are diverse in terms of resources and aspirations. The main objectives of this study are first to understand the diversity among maize-based smallholder farms and their current constraints in improving agricultural productivity in the Manica Plateau, Central Mozambique, and second, building on that understanding to explore options for biomass production either for food, cash or biofuel at farm level and contributions to maize availability in the region. The study was conducted in the Dombe and Zembe Administrative Posts. Farmers in the two posts cultivate both food and cash crops using the same resources, however, distances to the urban market differ, with Zembe close and Dombe far away from the markets. In addition, the agroecological conditions for crop production are more favourable in Dombe compared with Zembe. Using farm surveys, direct observations and on-farm measurements, followed by Principal Components Analysis (PCA) I identified land and labour as the variables that can best explain the variability found among smallholder farms (Chapter 2). Based on these variables I categorised farms into four Farm Types (FT): FT1. Large farms (4.4 ha in Dombe and 2.2 ha in Zembe), hiring in labour; FT2. Intermediate sized farms (1.9-1.2 ha), hiring in and out labour; FT3a. Small farms (1.1-0.9 ha), sharing labour; and FT3b. Small farms (1.0-0.7 ha), hiring out labour. The maize yield and maize labour productivities were higher on large farms (2.3 t ha-1 in Dombe and 2.0 t ha-1 in Zembe; 2.5×10-3 t h-1 in Dombe and 2.6 ×10-3 t h-1 in Zembe) compared with small farms (1.5 t ha-1 in Dombe and 1.1 t ha-1 in Zembe; 1.4×10-3 t h-1 in Dombe and 0.9×10-3 t h-1 in Zembe). The hiring in labour from small farms allowed large farms to timely weed their fields. Small farms were resource constrained and hired out labour (mutrakita) for cash or food to the detriment of weeding their own fields, resulting in poor crop yields. Excessive alcohol consumption by small farms also raised concerns on labour quality. Chapter 3 explored options aiming at addressing farmers’ objectives of being maize self-sufficient and increased gross margin and the contribution to national objective of producing food. A bio-economic farm model was used to investigate two pathways to increase agricultural production: (i) extensification, expanding the current cultivated area; and (ii) intensification, increasing input use and output per unit of land.

In the extensification pathway I considered the use of animal traction, herbicides and cultivators to save labour, whereas in the intensification pathway I explored the use improved varieties of maize, sesame, sunflower, pigeonpea and fertilizers. I focused on the large farms and the small farms hiring out labour as they represent both sides of the spectrum. The simulated results showed that combining labour and labour saving technologies substantially increased both gross margin and maize yields of large and small farms in both posts. Minor trade-offs is observed on large farms between the two goals whereas for small farms we see synergies between the goals. We concluded that prospects for increasing gross margin and food production are much better for large farms in Dombe compared with other farms. In Dombe, the maximum gross margin of large farms was 7530 $ y-1 per farm and maximum maize sales of 30.4 t y-1 per farm. In Zembe, the maximum gross margin of large farms (2410 $ y-1 per farm) and maximum maize sales (9.5 t y-1 per farm) were comparable to small farms in Dombe. I further assessed the impact of two biofuel investments (jatropha plantation and sunflower outgrower schemes) on farm level food security (food availability, access to food, stability of food, utilization of food). The results showed positive impact on small farms from employment on a jatropha plantation by increasing access to food and no impacts on intermediate and large farms. Impacts on food security from the sunflower outgrower scheme were minor which may be explained by the poor yields.

The need to link smallholder farmers to markets has been increasingly recognized as important strategy to promote rural development and poverty reduction. I developed an analytical framework, the Windmill Approach that looked at decision making at farm level to grow certain crops and at transaction strategies (Chapter 5). Through this framework I showed that a farmer decision to participate in a particular (new) value chain is determined by (a) the suitability of the new crop in the farm system (including the adaptability of the current farm system), and (b) the farmer’s experience with selling in various value chains. This has major policy implications as it highlights that to support smallholder farmers access to markets a holistic approach is needed that combines farming systems analysis and transaction cost theory.

In order to explore the opportunities for smallholder development there is need to understand the diversity of farms and farmers’ social and economic context. For large farms, in Central Mozambique farms with on average 2-4 ha of land, opportunities to improve their livelihoods through crop production can follow two pathways: intensification and extensification. Smallholders continue to produce staple food crops even when working on a plantation or participating in outgrower schemes. For small farms, off-farm opportunities such as those in a biofuel plantation are the best options to improve their livelihoods.

Assessing the case for sequential cropping to produce low ILUC risk biomethane : final report
Peters, Daan ; Zabeti, Masoud ; Kühner, Ann-Kathri ; Spöttle, Matthias ; Werf, Wopke van der; Stomph, Jan - \ 2016
Utrecht : ECOFYS Netherlands - 39
methane - biofuels - sequential cropping - farmers' associations - biogas - ancillary enterprises - farm management - agricultural energy production - transport - biobased economy - fuel crops - biomass production - methaan - biobrandstoffen - estafetteteelt - boerenorganisaties - nevenactiviteiten - agrarische bedrijfsvoering - energieproductie in de landbouw - brandstofgewassen - biomassa productie
In recent years and especially since the COP - 21 climate agreement reached in Paris last year, efforts to mitigate climate change accelerate. All sectors need to contribute in order to achieve the well below 2 degree climate target. The agricultural sector is relevant for climate change in various ways. Like the agricultural sector, the transport sector is also responsible for significant greenhouse gas emissions. Advanced biofuels and biogas produced from wastes and residues can play an increasingly important role in the transport mix. In Italy, 600 Italian farmers are organised in the Italian Biogas Council (Consorzio Italiano Biogas e Gassificazione, CIB). Some years ago, CIB members developed a concept that they coined Biogasdoneright. In collaboration with various research institutes they seeked for a way to combine biogas feedstock production with crop production for food and feed as a way to generate additional income in a sustainable manner. The core of the Biogasdoneright concept is that farmers apply sequential cropping by growing a winter cover crop on land that was previously fallow during winter time, while maintaining the main crop production during summer time as previously. Multiple claims can be made about Biogasdoneright, for example related to the large potential role for biogas in our future energy system. This project focussed on the most relevant claims related to the use of biomethane in transport, with a focus on sustainability aspects.
Methodologies identification and certification of Low ILUC risk biofuels : final report
Peters, Daan ; Spöttle, ; Hähl, Thomas ; Kühner, Ann-Kathrin ; Cuijpers, Maarten ; Stomph, Tjeerd Jan ; Werf, Wopke van der; Grass, Martin - \ 2016
Utrecht : ECOFYS Netherlands - 58
biofuels - greenhouse gases - land use - biomass - biomass production - biobased economy - indirect land use change - biobrandstoffen - broeikasgassen - landgebruik - biomassa - biomassa productie - indirecte veranderingen van landgebruik
Biofuels can be an important instrument to decarbonise the transport sector. However, the greenhouse gas performance of biofuels can be negatively impacted by Indirect land use change (ILUC) effects. In this report, Ecofys proposes two methodologies to identify and demonstrate low ILUC risk biofuel feedstock production through the application of yield increase (see Chapter 3) or unused land (see ILUC mitigation methodology for unused land).
Microbial electrosynthesis of biochemicals : innovations on biocatalysts, electrodes and ion-exchange for CO2 supply, chemicals production and separation
Bajracharya, S. - \ 2016
University. Promotor(en): Cees Buisman; David Strik; Deepak Pant. - Wageningen : Wageningen University - ISBN 9789462578531 - 181 p.
carbon dioxide - biofuels - chemicals - biocatalysis - ion exchange - electrodes - kooldioxide - biobrandstoffen - chemicaliën - biokatalyse - ionenuitwisseling - elektrodes

Microbial electrosynthesis (MES) is an electricity-driven production of chemicals from low-value waste using microorganisms as biocatalysts. MES from CO2 comprises conversion of CO2 to multi-carbon compounds employing microbes at the cathode which use electricity as an energy source. This thesis presents innovations on MES from CO2 using anaerobic mixed-cultures, circumventing the methane generation. Acetate was the primary product but other products including ethanol, butyrate were also produced. Establishment of active biocathode at the graphite felt cathode was achieved under long-term operation which led to the acetate accumulation up to 7-10 g L-1 at -1 V/Ag/AgCl cathode potential. CO2 reduction in MES requires continuous availability of CO2 and low cathode potential to ensure the supply of reducing equivalents/hydrogen. Use of gas diffusion biocathode doubled the CO2 mass-transfer rate which enhanced the production rates, reaching. Furthermore, a sustainable technology for manufacturing biochemicals/biofuels was demonstrated in this thesis by integrating the product separation in MES. The electricity-driven production of chemicals/biofuels from CO2/waste products and subsequent product recovery studies prospect an integration of microbial electrosynthesis with biorefineries for the up-scaling of both technologies.

Targets and tools for optimizing lignocellulosic biomass quality of miscanthus
Weijde, R.T. van der - \ 2016
University. Promotor(en): Richard Visser, co-promotor(en): Luisa Trindade; Oene Dolstra. - Wageningen : Wageningen University - ISBN 9789462578388 - 231 p.
miscanthus - bioethanol - biomass - biofuels - lignocellulose - fuel crops - plant breeding - cell walls - cell wall components - genetic diversity - genetic variation - biomass conversion - biobased economy - biomassa - biobrandstoffen - brandstofgewassen - plantenveredeling - celwanden - celwandstoffen - genetische diversiteit - genetische variatie - biomassaconversie

Miscanthus is a perennial energy grass characterized by a high productivity and resource-use efficiency, making it an ideal biomass feedstock for the production of cellulosic biofuels and a wide range of other biobased value-chains. However, the large-scale commercialization of converting biomass into cellulosic biofuel is hindered by our inability to efficiently deconstruct the plant cell wall. The plant cell wall is a complex and dynamic structure and its components are extensively cross-linked into an unyielding matrix. The production of biofuel depends on the extraction, hydrolysis and fermentation of cell wall polysaccharides, which currently requires energetically and chemically intensive processing operations that negatively affect the economic viability and sustainability of the industry. To address this challenge it is envisioned that the bioenergy feedstocks can be compositionally tailored to increase the accessibility and extractability of cell wall polysaccharides, which would allow a more efficient conversion of biomass into biofuel under milder processing conditions.

Extensive phenotypic and genetic diversity in cell wall composition and conversion efficiency was observed in different miscanthus species, including M. sinensis, M. sacchariflorus and interspecific hybrids between these two species. In multiple experiments a twofold increase in the release of fermentable sugars was observed in ‘high quality’ accessions compared to ‘low quality’ accessions. The exhaustive characterization of eight highly diverse M. sinensis genotypes revealed novel and distinct breeding targets for different bioenergy conversion routes. The key traits that contributed favourably to the conversion efficiency of biomass into biofuel were a high content of hemicellulosic polysaccharides, extensive cross-linking of hemicellulosic polysaccharides (revealed by a high content of trans-ferulic acids and a high ratio of arabinose-to-xylose), a low lignin content and extensive incorporation of para-coumaric acid into the lignin polymer.

Lignin is widely recognized as one of the key factors conveying recalcitrance against enzymatic deconstruction of the cell wall. The incorporation of para-coumaric acid into the lignin polymer is hypothesized to make lignin more easily degradable during alkaline pretreatment, one of the most widely applied processing methods that is used to pretreat biomass prior to enzymatic hydrolysis. Previous studies have shown that reducing lignin content is often implicated in reduced resistance of plants to lodging. We hypothesize that extensively cross-linked hemicellulosic polysaccharides may fulfil a similar function in supporting cell wall structural rigidity and increasing the content of hemicellulosic polysaccharides may be a way to reduce lignin content without adversely affecting cell wall rigidity. This strategy can be used to improve biomass quality for biobased applications, as hemicellulosic polysaccharides are more easily degradable during industrial processing than lignin. Furthermore, hemicellulosic polysaccharides adhere to cellulose, which negatively affects the level of cellulose crystallinity. Crystalline cellulose is harder to degrade than its more amorphous form. Therefore the reduction of cellulose crystallinity is another mechanism through which increasing the content of hemicellulosic polysaccharides positively contributes to cell wall degradability. These results provided new insights into the traits that may be targeted to improve the quality of lignocellulose feedstocks.

However, evaluation of complex biochemical traits for selection purposes is hindered by the fact that their accurate quantification is a costly, lengthy and laborious procedure. To overcome these limitations an accurate and high-throughput method was developed based on near-infrared spectroscopy. Through extensive calibration we developed accurate prediction models for a wide range of biomass quality characteristics, which may be readily implemented as a phenotyping tool for selection purposes.

Additionally, progress through breeding may substantially be improved by marker-assisted selection, which will reduce the need for the evaluation of genotype performance in multi-year field trials. To this end, a biparental M. sinensis mapping population of 186 individuals was developed and genotyped using a genotyping-by-sequencing approach. A total of 564 short-sequence markers were used to construct a new M. sinensis genetic map. Cell wall composition and conversion efficiency were observed to be highly heritable and quantitatively inherited properties. This is the first genetic study in miscanthus to map quantitative trait loci (QTLs) for biomass quality properties and is a first step towards the application of marker-assisted selection for biomass quality properties.

Through the evaluation of a diverse set of miscanthus genotypes in multiple locations we demonstrated that in addition to genotypic variation, growing conditions may have a substantial influence on cell wall composition and conversion efficiency. While further research is needed to identify which specific environmental parameters are responsible for the observed effects, these results clearly indicate that the environmental influence on biomass quality needs to be taken into account in order to match genotype, location and end-use of miscanthus as a lignocellulose feedstock. Moreover, significant genotype-by-environment interaction effects were observed for cell wall composition and conversion efficiency, indicating variation in environmental sensitivity across genotypes. Although the magnitude of the genotypic differences was small in comparison to genotype and environmental main effects, this affected the ranking of accession across environments. Stability analysis indicated some stable accessions performed relatively across diverse locations.

In addition to trialing miscanthus in diverse locations, we also evaluated miscanthus biomass quality under drought conditions for a number of reasons: 1) drought stress is linked to a differential expression of cell wall biosynthesis genes, 2) incidence of drought events is increasing due to climate change, 3) irrigation is likely to be uneconomical during the cultivation of miscanthus and 4) miscanthus has many characteristics that make it a crop with a good potential for cultivation on marginal soils, where abiotic stresses such as drought may prevail. Drought stress was shown to result in a large reduction in cell wall and cellulose content and a substantial increase in hemicellulosic polysaccharides and cellulose conversion rates. We hypothesized that the reduction in cellulose content was due to an increase in the production of osmolytes, which are well-known for their role in plant protection against drought. The results indicated that drought stress had a positive effect on the cell wall degradability of miscanthus biomass.

Overall the compendium of knowledge generated within the framework of this thesis provided insights into the variation in biomass quality properties in miscanthus, increased our understanding of the molecular, genetic and environmental factors influencing its conversion efficiency into biofuel and provided tools to exploit these factors to expand the use of miscanthus as a lignocellulose feedstock.

Biofuel production in Vietnam : Greenhouse gas emissions and socioeconomic impacts
Thanh, L. le - \ 2016
University. Promotor(en): Ekko van Ierland; Xueqin Zhu. - Wageningen : Wageningen University - ISBN 9789462576186 - 197 p.
biofuels - greenhouse gases - environmental economics - emission - socioeconomics - fuels - natural resources - vietnam - biobrandstoffen - broeikasgassen - milieueconomie - emissie - sociale economie - brandstoffen - natuurlijke hulpbronnen
The overall objective of this thesis is to study the energy efficiency, GHG emission savings, and the economic viability of biofuels as energy for transportation and to examine the impacts of biofuel policies on food production, welfare, and emission in Vietnam.
An economic model for offshore cultivation of macroalgae
Dijk, Wim van; Schoot, Jan Rinze van der; Edwards, Maeve ; Queguineur, Benoit ; Champenois, Jennifer ; Mooney, Karen ; Barrento, Sara - \ 2015
Swansea : Swansea University - 21
biobased economy - biomass - biofuels - algae - algae culture - oils - seaweeds - seaweed culture - biomassa - biobrandstoffen - algen - algenteelt - oliën - zeewieren - zeewierenteelt
Algae biomass is considered as a potential non-fossil source of raw materials to produce fuel, feed, chemicals and materials. For this purpose microalgae as well as macroalgae can be used, and in this report we focus on the latter. More than 99% of the world production of aquatic plants is produced in Asia (FAO 2012, Table 1). From the remaining 1% about 4% is cultivated in Europe. Important European countries with commercial seaweed cultivation are Denmark, Ireland and France. Depending on their pigmentation seaweed species are commonly grouped in brown, red and green seaweeds.
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