Recent Submissions

  • Production of polyhydroxyalkanoates from waste frying oil by Cupriavidus necator

    Verlinden, Rob A. J.; Hill, David J.; Kenward, Melvin A.; Williams, Craig D.; Piotrowska-Seget, Zofia; Radecka, Iza K. (Springer, 2011)
    Polyhydroxyalkanoates (PHAs) are biopolymers, which can replace petrochemical plastics in many applications. However, these bioplastics are currently far more expensive than petrochemical plastics. Many researchers are investigating the use of inexpensive substrates derived from waste streams. Waste frying oil is abundant and can be used in PHA production without filtration. Cupriavidus necator (formerly known as Ralstonia eutropha) is a versatile organism for the production of PHAs. Small-scale batch fermentation studies have been set up, using different concentrations of pure vegetable oil, heated vegetable oil and waste frying oil. These oils are all rapeseed oils. It has been shown that Cupriavidus necator produced the homopolymer polyhydroxybutyrate (PHB) from the rapeseed oils. The achieved PHB concentration from waste frying oil was 1.2 g/l, which is similar to a concentration that can be obtained from glucose. The PHB harvest from pure oil and heated oil was 0.62 g/l and 0.9 g/l respectively. A feed of waste frying oil could thus achieve more biopolymer than pure vegetable oil. While the use of a waste product is beneficial from a life-cycle perspective, PHB is not the only product that can be made from waste oil. The collection of waste frying oil is becoming more widespread, making waste oil a good alternative to purified oil or glucose for PHB production.
  • Seasonal variation and municiple solid waste composition—issues for development of new waste management strategies in Abuja, Nigeria

    Roberts, Clive L.; Watkin, Glynne; Ezeah, Chukwunonye; Phillips, Paul S.; Odunfa, Amos (Widener University School of Engineering and the National Center for Resource Management and Technology at the University of Pennsylvania, 2010)
    The state of solid waste management in cities of developing countries like Nigeria is a major social/environmental challenge. While research to understand the nature of the barriers to sustainable management methods have been carried out, the impact of seasonal changes in waste composition and practice is still in its infancy in developing countries. This paper investigates seasonal variation in municipal solid waste composition in Abuja, Nigeria, a classic tropical urban environment. Weekly waste collections from eighty randomly selected dwellings in Garki District of Abuja Municipality were sampled and analyzed at two peaks of the main tropical seasons: January-February (dry season) and August-September (wet season) in 2008. Results of compositional analysis and physical characterization were statistically analyzed and indicate that waste stream has approximately 11% and 60% recyclable and biodegradable components respectively. This investigation finds no significant difference in the proportion of biodegradable components of the waste stream from both seasons. Findings from this investigation helped develop strategies designed to improve current management practices.
  • The development of sustainable cropping systems in the highlands of South-East Asia: general lessons for development projects

    Fullen, Michael A. (Brazil: Universidade Federal de Uberlândia (UFU), 2005)
    Soil conservation in the highlands of South-East Asia is essential for sustainable agro-environmental development. The effectiveness of soil conservation treatments developed in runoff plots was investigated in farmer-managed plots on a natural catchment. This was achieved by the development and scientific evaluation of modified and novel cropping practices in a representative highland catchment in Yunnan Province, China. Wang Jia Catchment covers 40.1 hectares near Kedu, in Xundian County, north-east Yunnan (25o28'N, 102o53'E). The initial project consisted of an evaluation of the effects of modified cropping practices on maize productivity and soil properties. This programme was extended to investigate ways of increasing the productivity of maize, wheat and soybean on fragile slopes in a sustainable and environmentally-friendly way. The approach incorporates modified and novel agronomic and soil conservation measures, with the evaluation of their agricultural, environmental and socio-economic impacts using multidisciplinary approaches. This European Union funded project involved an international research team from Belgium, China, Ireland, Thailand and the U.K. Five co-ordinated work packages were implemented. Involving: (1) Background agricultural and environmental assessment of Wang Jia Catchment. (2) Implementation and evaluation of modified and novel cropping systems for wheat, maize and soybean in the catchment. (3) Cost-benefit analyses of the socio-economic impacts of the changed cropping practices. (4) Comparative scientific evaluation of the cropping techniques in the highlands of northern Thailand. (5) Dissemination of project outcomes and establishment of training programmes for best practice in highland rural development. The lessons of the Project for promoting sustainable agro-environmental development in tropical and subtropical highlands include: (1) Recognizing the importance of both ‘north-south’ and ‘south-south’ co-operation in development projects, (2) Integrating local people as full partners in the research programme, (3) Matching the different ‘time horizons’ of the different stakeholders and (4) Developing multidisciplinary teams, including biophysical scientists and socio-economists.
  • An awareness-adoption matrix for strategic decision making in agricultural development projects: a case study in Yunnan Province, China

    Subedi, Madhu; Hocking, Trevor J.; Fullen, Michael A.; McCrea, Alison R.; Milne, E.; Wu, Bozhi; Mitchell, David J. (Amsterdam: Elsevier, 2009)
    Significant achievements have been made in generating sustainable agricultural technologies in developing countries. Usually, these new technologies have been more effective in increasing production and productivity than existing technologies. However, many new technologies considered ‘effective’ have not been successful in alleviating the associated sustainability problems, due to poor adoption by targeted users. Success of any novel technical intervention should be judged on the basis of how widespread adoption is in the target area by targeted users. In this context, a case study identified the factors affecting farmers’ adoption of improved technologies extended by an agricultural development project in a rural Village in Yunnan Province, China. Initial adoption/adaptation of project technologies was influenced by farmers’ awareness of the technology. Farmers were more aware of polythene mulch, contour cultivation, intercropping and tree planting technologies than others. This led to a comparatively high initial uptake of polythene mulch, contour cultivation, sweet chestnut, and intercropping technologies. Farmers had inadequate knowledge about some Project technologies, the adoption of which was particularly low. This reveals the need for increasing farmers’ awareness about the rationale for Project technologies to achieve greater adoption/adaptation of project technologies by farmers over wider areas. Farmers’ testing of the technology leads to better adoption/adaptation compared to mere awareness. However, considerable time and resources are required for testing/trying technologies. This justifies the usefulness of comparatively quick and less resource demanding options for awareness creation. Development of effective cropping technologies is important for sustainable agricultural development. The success of any agricultural development project, especially in terms of improving sustainability, depends on how widely those improved technologies are adopted/adapted by farmers in the targeted region. Therefore, farmers’ adoption of technologies should be a key criterion for judging the success of any project. The awareness-adoption matrix is a useful tool to guide research and development projects to achieve expected adoption/adaptation of technologies. Use of the matrix helps identification of weak and strong aspects of research and development projects and thus assists strategic decision-making.
  • Use of farmers' indicators to evaluate the sustainability of cropping systems on sloping land in Yunnan Province, China.

    Subedi, Madhu; Hocking, Trevor J.; Fullen, Michael A.; McCrea, Alison R.; Milne, E.; Wu, Bozhi; Mitchell, David J. (Elsevier, 2009)
    Diversity in the biophysical and socio-economic attributes of agricultural systems makes them uniquely niche based. Farmers are expert in local biophysical and socio-economic situations and can contribute in developing pragmatic indicators of agro-environmental development. During evaluation of an agricultural research project in Yunnan, China, local farmers were capable of evaluating the effects of modified technologies on existing cropping systems and discussed their attitudes to the interventions using their own indicators. Farmers' response can be grouped into seven major aspects: i) effects on income, ii) effects on production resources, iii) effects on crop management, iv) existing local knowledge about the technology, v) availability of inputs, vi) access to information, and vii) socio-economic conditions of farming households. Farmers concluded that environmental conditions in the experimental catchment in comparison to an adjacent untreated catchment were better in terms of soil and water losses, vegetation cover and natural resources, infrastructures and catchment management, use of environmentally-friendly technologies, and crop productivity. Success in soil and water conservation programmes depends on the efforts of the farmers and other local users and their greater involvement helps to identify more pragmatic indicators. Furthermore, it increases ownership of the programme, enhances interactions with the project scientists, increases farmers' awareness of agro-environmental problems and their possible consequences. These development will enable scientists to develop better targeted interventions and increase the likelihood of adoption of tested technologies by local communities. The use of paired adjacent catchments improved evaluation activities and is proposed as good practice for future catchment improvement programmes.
  • An evaluation of the introduction of modified cropping practices in Yunnan Province, China, using surveys of farmers' households

    Subedi, Madhu; Hocking, Trevor J.; Fullen, Michael A.; McCrea, Alison R.; Milne, E.; Mitchell, David J.; Wu, Bozhi (Chinese Academy of Agricultural Sciences. Published by Elsevier B.V., 2009)
    Problems associated with land degradation are serious in China. Sloping land in South China has experienced a decline in crop productivity by 30-60% due to soil erosion and it has been predicted that most topsoil will be lost within the next 100 years if current erosion rates continue. Considering these situations, an agro-environmental research and development project (Sustainable Highland Agriculture in South-East Asia – SHASEA) was conducted in a catchment in Yunnan Province, China, to address the objectives of increasing crop productivity in sustainable and environmentally-friendly ways. A range of cropping practices was developed and implemented in a rural upland catchment (Wang Jia). At the end of the project, farmers were surveyed to evaluate project effectiveness. All farmers from Wang Jia Catchment, who were involved in project implementation, were surveyed. A sample of farmers working in an adjacent catchment (not associated with the project) was surveyed for comparative purposes. Farmers had different perceptions of the cropping practices employed. Contour cultivation was preferred and likely to be adopted. Others practices such as straw mulching and intercropping were seen as less appropriate and unlikely to be adopted. Polythene mulch was recognized as effective, but likely to be adopted only if financial returns were favourable. The availability of relevant information had an important impact on the extent of technology testing by farmers and their willingness to adopt the practices in the future.
  • Bacterial synthesis of biodegradable polyhydroxyalkanoates.

    Verlinden, Rob A. J.; Hill, David J.; Kenward, M.A.; Williams, Craig D.; Radecka, Izabela (Wiley InterScience, 2007)
    Various bacterial species accumulate intracellular polyhydroxyalkanoates (PHAs) granules as energy and carbon reserves inside their cells. PHAs are biodegradable, environmentally friendly and biocompatible thermoplastics. Varying in toughness and flexibility, depending on their formulation, they can be used in various ways similar to many nonbiodegradable petrochemical plastics currently in use. They can be used either in pure form or as additives to oil-derived plastics such as polyethylene. However, these bioplastics are currently far more expensive than petrochemically based plastics and are therefore used mostly in applications that conventional plastics cannot perform, such as medical applications. PHAs are immunologically inert and are only slowly degraded in human tissue, which means they can be used as devices inside the body. Recent research has focused on the use of alternative substrates, novel extraction methods, genetically enhanced species and mixed cultures with a view to make PHAs more commercially attractive.
  • Developmental regulation of mannan, arabinogalactan-protein and pectic epitopes in pistils of Vicia faba (faba bean)

    Chen, Wen; Stoddard, Fred L.; Baldwin, Timothy C. (University of Chicago Press, 2006)
    Cell walls of the stigma and style are important zones for cell‐cell recognition, nutrition, guidance, and protection of the pollen tube along the transmitting tract. The objective of this study was to investigate the modulation of selected cell wall epitopes during pistil development in the crop species Vicia faba L. (faba bean). An immunocytochemical investigation of pistil development was performed using a panel of four anti–cell wall/plasma membrane antibodies at both light and electron microscope levels during the 4 days leading up to anthesis. The selected antibodies recognized mannan‐containing polysaccharides (antimannan antisera), β‐1,4‐galactan (LM5), α‐1,5‐l‐arabinan (LM6), and arabinogalactan/arabinogalactan‐protein (AG/AGP) epitopes, with GlcpUA‐β‐1,→3‐d‐GalpUA‐α‐1,→2‐l‐Rha trisaccharide motifs (JIM13). Mannan accumulation was shown to be associated with the formation and maturation of sclerenchyma cells and xylem elements. The β‐1,4‐galactan and α‐1,5‐l‐arabinan epitopes were highly expressed in the walls of parenchyma and epidermis in a developmentally regulated manner. AG/AGP epitopes were particularly abundant in the stigma and cells lining the stylar canal, together with the α‐1,5‐l‐arabinan epitope recognized by LM6. These data suggest an association of AGs/AGPs with pollen tube growth, of mannan with strengthening and stiffening the pistil, and of β‐1,4‐galactan and α‐1,5‐l‐arabinan components with tissue flexibility within the pistil.
  • Identification and characterization of GONST1, a golgi-localized GDP-mannose transporter in Arabidopsis.

    Baldwin, Timothy C.; Handford, Michael G.; Yuseff, Maria-Isabel; Orellana, Ariel; Dupree, Paul (American Society of Plant Biologists, 2001)
    Transport of nucleotide sugars across the Golgi apparatus membrane is required for the luminal synthesis of a variety of plant cell surface components. We identified an Arabidopsis gene encoding a nucleotide sugar transporter (designated GONST1) that we have shown by transient gene expression to be localized to the Golgi. GONST1 complemented a GDP-mannose transport-defective yeast mutant (vrg4-2), and Golgi-rich vesicles from the complemented strain displayed increased GDP-mannose transport activity. GONST1 promoter::beta-glucuronidase studies suggested that this gene is expressed ubiquitously. The identification of a Golgi-localized nucleotide sugar transporter from plants will allow the study of the importance of this class of proteins in the synthesis of plant cell surface components such as cell wall polysaccharides.
  • DcAGP1, a secreted arabinogalactan protein, is related to a family of basic proline-rich proteins.

    Baldwin, Timothy C.; Domingo, Concha; Schindler, Thomas; Seetharaman, Gouri; Stacey, Nicola; Roberts, Keith (Springer Verlag, 2001)
    A cDNA corresponding to the core protein of an immunoaffinity-purified arabinogalactan protein (AGP) secreted aucus carota (carrot) cells in liquid culture was isolated. This cDNA, DcAGP1, encodes a new class of non-classical' AGP with strong similarity to a family of basic proline-rich proteins. The protein is rich in proline (17%), alanine (10%) and lysine (11%) and contains four distinct domains: a signal peptide, a proline-rich domain, a histidine-rich basic domain and a cysteine-containing 'PAC' domain that is found in a range of other cell wall proteins. The protein contains several sequence motifs found in otherwise unrelated cell wall proteins, but also displays some unique features. Northern blot analyses show that while the DcAGP1 transcript is abundant in the suspension-culture cells from which the AGP was obtained; in carrot seedlings the gene is only expressed at low levels in the roots and it is neither wound- nor stress-inducible. Furthermore, northern and western blot analyses demonstrate that the core polypeptide of DcAGP1 is differentially glycosylated in two different carrot suspension cultures. The unusual features of the protein sequence suggest that the DcAGP1 protein is a member of a family of basic proline-rich proteins defined by the C-terminal PAC domain, and the possible function(s) of the DcAGP1 protein is considered in the light of current views on AGP structure and function.
  • Localisation and characterisation of cell wall mannan polysaccharides in Arabidopsis thaliana

    Handford, Michael G.; Baldwin, Timothy C.; Goubet, Florence; Prime, Tracy A.; Miles, Joanne; Yu, Xiaolan; Dupree, Paul (Springer-Verlag, 2003)
    Polysaccharides containing b-1,4-mannosyl residues (mannans) are abundant in the lignified secondary cell walls of gymnosperms, and are also found as major seed storage polysaccharides in some plants, such as legume species. Although they have been found in a variety of angiosperm tissues, little is known about their presence and tissue localisation in the model angiosperm, Arabidopsis thaliana (L.) Heynh. In this study, antibodies that specifically recognised mannans in competitive ELISA experiments were raised in rabbits. Using these antibodies, we showed that Golgi-rich vesicles derived from Arabidopsis callus were able to synthesise mannan polysaccharides in vitro. Immunofluorescence light microscopy and immunogold electron microscopy of Arabidopsis inflorescence stem sections revealed that the mannan polysaccharide epitopes were localised in the thickened secondary cell walls of xylem elements, xylem parenchyma and interfascicular fibres. Similarly, mannan epitopes were present in the xylem of the leaf vascular bundles. Surprisingly, the thickened epidermal cell walls of both leaves and stems also contained abundant mannan epitopes. Low levels were observed in most other cell types examined. Thus, mannans are widespread in Arabidopsis tissues, may be of particular significance in both lignified and non-lignified thickened cell walls. Polysaccharide analysis using carbohydrate gel electrophoresis (PACE) of cell wall preparations digested with a specific mannanase showed that there is glucomannan in inflorescence stems. The findings show that Arabidopsis can be used as a model plant in studies of the synthesis and functions of mannans.