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Wednesday, 21 June 2017

Isolation and structural characterization of cellulose nanocrystals extracted from garlic straw residues

Published Date
Received 29 January 2016, Revised 18 April 2016, Accepted 21 April 2016, Available online 30 April 2016.

 Author
Fatma Kallel. Author links open the author workspace.Opens the author workspaceOpens the author workspacea. Numbers and letters correspond to the affiliation list. Click to expose these in author workspaceFedia Bettaieb. Author links open the author workspace.b. Numbers and letters correspond to the affiliation list. Click to expose these in author workspacec. Numbers and letters correspond to the affiliation list. Click to expose these in author workspaced. Numbers and letters correspond to the affiliation list. Click to expose these in author workspaceRamzi Khiari. Author links open the author workspace.Opens the author workspaceOpens the author workspaceb. Numbers and letters correspond to the affiliation list. Click to expose these in author workspacec. Numbers and letters correspond to the affiliation list. Click to expose these in author workspaced. Numbers and letters correspond to the affiliation list. Click to expose these in author workspaceAraceli García. Author links open the author workspace.c. Numbers and letters correspond to the affiliation list. Click to expose these in author workspacee. Numbers and letters correspond to the affiliation list. Click to expose these in author workspaceJulien Bras. Author links open the author workspace.c. Numbers and letters correspond to the affiliation list. Click to expose these in author workspaced. Numbers and letters correspond to the affiliation list. Click to expose these in author workspaceSemia Ellouz Chaabouni. Author links open the author workspace.a. Numbers and letters correspond to the affiliation list. Click to expose these in author workspacef. Numbers and letters correspond to the affiliation list. Click to expose these in author workspace
a
Enzyme Bioconversion Unit (04/UR/09-04), National School of Engineering, Sfax University, P.O. Box 1173-3038, Tunisia
b
University of Monastir, Faculty of Sciences, UR13 ES 63—Research Unity of Applied Chemistry & Environment, 5000 Monastir, Tunisia
c
University of Grenoble Alpes, LGP2, F-38000 Grenoble, France
d
CNRS, LGP2, F-38000 Grenoble, France
e
University of the Basque Country UPV/EHU, Department of Chemical and Environmental Engineering, 20018 San Sebastián, Spain
f
Common Service Unit of Bioreactor Coupled with an Ultrafilter, National School of Engineering, Sfax University, P.O. Box 1173-3038, Tunisia
Highlights
•
High aspect ratio cellulose nanocrystals were extracted from garlic straw residues.
•
The crystallinity index of the extracted CNCs is found to be 68%.
•
Rod-like CNCs have diameters of 6 nm and length 480 nm as revealed by TEM and AFM.
Abstract
The aim of this study was to explore the utilization of garlic straw residues as source for the production of cellulose nanocrystals (CNC). Garlic straw (GS) was first purified using chemical alkali extraction (ATGS) and then bleached (BGS) before the production of cellulose nanocrystals (CNC-GS) by acid hydrolysis (H2SO4). The chemical composition of GS was determined according to TAPPI standards and showed that it is composed by 41% wt cellulose, 18% wt hemicelluloses and 6.3% wt lignin, among other components. Then, the obtained fibers were extracted and characterized by several techniques such as X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The Fourier transform infrared spectroscopy (FTIR) spectra showed changes in the peaks at 1731, 1556 and 1244 cm−1, indicating that the alkali treatment partially removed hemicelluloses and lignin from the fiber surface. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) techniques were used to investigate the morphology of the produced CNC. The crystallinity index of the GS was 37.4%, and it increased to more than 68% after the acid hydrolysis. The garlic straw had better thermal stability than those of the cellulose obtained after the bleaching treatment and of the nanocrystals isolated following acid hydrolysis. The CNC presented a needle-shaped nature, an average diameter and length of 6 nm and 480 nm, respectively, leading to an aspect ratio of approximately 80. These promising results proved revalue of this by-product for the production of CNC and its potential use as reinforcement in the preparation of nanocomposites.

Graphical abstract

Keywords

Garlic straw
Chemical composition
Morphology behavior
Cellulose nanocrystals
Acid hydrolysis
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Genetically modified crops in Africa: Economic and policy lessons from countries south of the Sahara

Author
Edited by Jose Benjamin Falck-Zepeda (j.falck-zepeda@cgiar.org), Gruère, Guillaume P. and Idah Sithole-Niang

Abstract: A variable climate, political instability, and other constraints have limited agricultural development in African countries south of the Sahara. Genetically modified (GM) crops are one tool for enhancing agricultural productivity and food security despite such constraints. Genetically Modified Crops in Africa: Economic and Policy Lessons from Countries South of the Sahara investigates how this tool might be effectively used by evaluating the benefits, costs, and risks for African countries of adopting GM crops. The authors gather together studies on GM crops’ economic effects and impact on trade, how consumers view such crops, and other issues. They find that GM crops have had, on average, a positive economic effect in the nations where they were used and identify future steps for enhancing GM crop adoption’s positive effects. Promising policy initiatives include making biosafety regulations that do not make GM crop development prohibitively expensive, fostering intraregional trade in GM crops, and providing more and better information about GM crops to consumers who might currently be skeptical of them. These and other findings in Genetically Modified Crops in Africa indicate ways biotechnology can contribute to economic development in Africa south of the Sahara.
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Genetically modified cotton in Uganda: An ex ante evaluation

Author
Daniela Horna, Patricia Zambrano (p.zambrano@cgiar.org), Jose Benjamin Falck-Zepeda, Theresa Sengooba and Miriam Kyotalimye
Authors registered in the RePEc Author Service: José Benjamin Falck Zepeda (j.falck-zepeda@cgiar.org)

Abstract: The Ugandan government has recognized the need to increase the per¬formance of cotton and the potential of crop biotechnologies, particu¬larly the role of genetically modified (GM) varieties to improve cotton production and thus the economy in general. In 2008, the National Biosafety Committee of Uganda approved the guidelines for implementing con¬fined trials, which enabled testing the environmental safety and performance of insect-resistant (Bt) and herbicide-tolerant (HT) cotton varieties. The implementation of the confined trials started in May 2009.
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Transgenics in Indian Agriculture: Experiences so far and implications of KIA proposals on Indian Farmers

Author
Ramanjaneyulu G V

Abstract: KIA proposes to bring a paradigm shift in Indian Agriculture in terms of human resource development, research, technology generation, technology dissemination and commercialization. In the short run, the KIA would concentrate on the four themes namely, (i) education, learning resources, curriculum development and training, (ii) food processing, use of byproducts, and biofuels, (iii) biotechnology and (iv) water management. [Proceedings of KIA Workshop].
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Property claims in genetically and non-genetically modified crops: intellectual property rights vs. brand property rights in postindustrial knowledge societies

Author
Bernhard Gill

Abstract: Conceptualising the ongoing conflict over genetically modified vs. non-genetically modified crops in the frame of property rights, one can see that economic valorisation dynamics and aspirations are working on both sides, within two differently evolving agri-food paradigms, with biotechnology companies propagating intellectual property rights on seeds and crops within a productivist strategy, and with retailer chains, non-governmental organisations and farmer associations claiming generic names and labels as public property rights on identity-preserved crops within a consumerist strategy. The analysis shows that the direction and strength of the dynamics is highly dependent on the physical intricacies and social relations implicated in these two types of intangible property. As the development of intangible property rights lies at the heart of postindustrial knowledge economies, the study of the genetically modified conflict is also instructive for understanding social change in the agri-food sector and in society more generally.
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The role of global R%D networks in generating social capital for born-global bio-tech firms: a multi-case approach

Author
Amon Simba
International Journal of Entrepreneurship and Small Business, 2013, vol. 20, issue 3, pages 342-362

Abstract: The traditionally auspicious 'Big Pharma' business model in the pharmaceutical industry is rapidly evolving. Large pharmaceutical companies are re-configuring their business models to achieve operational efficiency. The preferred option appears to be out-sourcing science-related R%D as opposed to conducting the research in-house. This has marked the 'birth' of born-global bio-tech firms which operate as contract research organisations. The firms are owner-managed by entrepreneurial scientists who generate social capital in the form of scientific knowledge and technical know-how by participating in multifarious global R%D networks. In that sense, this empirical study utilises multiple cases of born-global bio-tech firms sampled from the East Midlands in the UK to investigate how various mechanisms in their knowledge supply-chain (global networks), including complex business and social relationships, shape their social capital generating strategies. By doing so, the study contributes to the concept of dynamic capabilities and networking. The study is also invaluable to a number of stakeholders including: large and small firms, other researchers, and policy makers.
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Early stage technology investments of pre-seed venture capitalists

Author
Gunter Festel, Pablo Breitenmoser, Martin Würmseher and Jan Kratzer
International Journal of Entrepreneurial Venturing, 2015, vol. 7, issue 4, pages 370-395

Abstract: Although technology transfer offices at universities are widely installed, in many cases, inventions made in academia still struggle to be commercialised. This so-called technology transfer gap can be overcome by professionalised pre-founding activities. Whereas prevailing investment models, like business angels or traditional venture capitalists, usually tie up their business activity on already founded companies, pre-seed venture capitalists (PSVC) attempt to align inventions made at academia with entrepreneurship by founding start-ups. Against this background, this study aims at examining the perceptions of deficiencies of the prevailing investment models and the role of the PSVCs in the pre-founding phase. PSVC companies operating in the biotechnology and nanotechnology area and with a broader technology approach have been analysed within a multi case study research. The results show that based on the technological scope and the financial source of the investment activity, four different types of PSVC business models can be identified and described. Technology transfer offices at universities and research institutions supporting the founding process of start-ups can use the findings to develop and execute specific partnership strategies with these PSVC types.
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GM agricultural technologies for Africa: A state of affairs

Author
Judith A. Chambers, Patricia Zambrano (p.zambrano@cgiar.org), Falck-Zepeda, José Benjamin, Gruère, Guillaume P., Debdatta Sengupta and Karen Hokanson
Authors registered in the RePEc Author Service: José Benjamin Falck Zepeda (j.falck-zepeda@cgiar.org)

Abstract: The African Development Bank (AfDB), in commissioning this report to be prepared by the International Food Policy Research Institute (IFPRI), highlighted the need for a comprehensive, evidenced-based review of agricultural biotechnology in order to better understand its current status, issues, constraints, and opportunities for Africa. Agricultural biotechnology comprises several scientific techniques (genetic engineering, molecular marker-assisted breeding, the use of molecular diagnostics and vaccines, and tissue cul­ture) that are used to improve plants, animals, and microorganisms. However, in prepar­ing this desktop analysis, IFPRI has focused on genetic modification (GM) technologies in particular and on the agricultural context in which they are being applied, because GM technologies are at the center of the controversy about biotechnology’s role in Africa. In addition, because we have attempted to focus our review on peer-reviewed evidence and documented examples, the preponderance of data presented in the report is focused on genetically modified (also abbreviated GM) crops in use and under development, although we recognize the potential of the technology for livestock, fisheries, and forestry.
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Cognitive Biases in the Assimilation of Scientific Information on Global Warming and Genetically Modified Food

Author
Brandon R. McFadden and Jayson Lusk (jlusk@purdue.edu)

Abstract: The ability of scientific knowledge to contribute to public debate about societal risks depends on how the public assimilates information resulting from the scientific community. Bayesian decision theory assumes that people update a belief by allocating weights to a prior belief and new information to form a posterior belief. The purpose of this study was to determine the effects of prior beliefs on assimilation of scientific information and test several hypotheses about the manner in which people process scientific information on genetically modified food and global warming. Results indicated that assimilation of information is dependent on prior beliefs and that the failure to update beliefs in a Bayesian fashion is a result of several factors including: misinterpreting information, illusionary correlations, selectively scrutinizing information, information-processing problems, knowledge, political affiliation, and cognitive function.
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Agricultural Resources and Environmental Indicators, 2012 Edition

Author
Craig D. Osteen and Utpal Vasavada

Abstract: Agricultural Resources and Environmental Indicators, 2012, describes trends in economic, structural, resource, and environmental indicators in the agriculture sector, focusing on changes since the release of Agricultural Resources and Environmental Indicators, 2006. These indicators are useful to assess important changes in U.S. agriculture—the industry’s development; its environmental effects; and the implications for economic, social, and environmental sustainability. This report tracks key resources, including natural, produced, and management resources, that are used in and affected by agricultural production, as well as structural changes in farm production and the economic conditions and policies that influence agricultural resource use and its environmental impacts. Each chapter provides a concise overview of a specific topic with links to sources of additional information.
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http://purl.umn.edu/132048 (application/pdf)
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Advantages and Disadvantages of Fasting for Runners

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