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Nanobiocatalytic Conversion of Agri-Food Waste into Biochemical Products
No full textPh.D. thesisAgri-food waste reduction is a huge priority for many nations including India to develop a resilient food ecosystem. The unavoidable agri-food waste is becoming a major threat to our efforts to alleviate global hunger along with safeguarding socio-economic and environmental interests. On contrary, such waste exhibits immense potential to be repurposed for industrial bioprocessing that could contribute to circular bioeconomy. It is critical to understand ways how we can utilize non-edible waste in generating value-added products via advanced transformation strategies that lead to a more sustainable and prosperous future. The present work thus demonstrates a viable ‘waste-to-feed’ strategy for valorizing agri-food waste using ‘nanobiocatalyst’ with potential benefits. Sugarcane bagasse and potato-peel waste were considered the model representatives of waste from agriculture and food–processing sectors, respectively. The work is broadly classified into three major sections; (i) developing a facile pre-treatment approach for agri-food waste, (ii) fabrication of individual nanobiocatalytic systems involving cellulase and α-amylase enzymes onto halloysite nanotubes (HNTs) as immobilizing template, and (iii) nanobiocatalyst-assisted valorization of agri-food waste to value-added products such as glucose, fructose syrup, and other hydrolysates. These products were employed as medium-alternative for industrial bioprocessing, fermentation and bio-cementation applications.
Developing an eco-friendly and facile pre-treatment process is essential for effective bioprocessing of lignocellulosic biomass. A two-step pretreatment approach was developed in this study, employing a solid acid catalyst, i.e., sulfonic acid functionalized magnetic halloysite nanotubes. Acid-functionalized magnetic halloysite nanotubes (MHNTs) were fabricated via mercaptosilane grafting and subsequent oxidation. The solid acid catalyst treatment followed by dilute alkaline treatment of sugarcane bagasse resulted in a more effective removal of hemicellulose (75.27%) and lignin (60.02%) contents from the biomass. The catalyst was easily recoverable using a magnet and could be reused over five consecutive cycles. The presence of high xylose (18.76 g/L) and low concentrations of inhibitory products in wash liquids indicated the effectiveness of the pretreatment approach employed. Sugarcane bagasse after solid-acid catalyst pre-treatments was more amenable towards enzymatic hydrolysis resulting in 60.32% cellulose saccharification. A 2.63-fold higher ethanol production was achieved using pre-treated sugarcane bagasse than its raw form, validating the effectiveness of the pre-treatment approach.
A quest for efficient biotransformation of cellulosic material into sustainable biochemical products for recent biotechnological interventions is currently under way. Herein, the fabrication of nanobiocatalyst (NBC) employing halloysite nanotubes (HNTs) as a template for immobilizing cellulase enzyme was attempted, which catalyzed the hydrolysis of cellulose into glucose. Magnetic character was imported to HNTs by in situ anchoring of iron oxide nanoparticles, onto which cellulase was immobilized using aminosilane surface functional chemistry. Characterization studies revealed nanobiocatalyst to be extremely stable during heterogeneous catalysis without compromising their catalytic activity. The optimization of process parameters yielded ∼93.5% activity of cellulase with high enzyme loading (111.6 mg/g support) after immobilization. Immobilized cellulase displayed superior stability at elevated temperatures (≥60°C) and storage capability compared with their free forms. The NBC even retained ∼68.2% of its original activity after seven consecutive uses with a minimum yield of 25.4 mg glucose/g cellulose and was 100% recoverable using a magnet. Displaying a high ionic-liquid tolerance ability is concurrent with superior catalytic potential against CMC and extracted cellulose (pretreated sugarcane bagasse), and achieving ∼50.2% saccharification and 0.56 g glucose/g cellulose within 48 h of continuous operation establishes the commercial viability of using cellulase-immobilized HNTs for efficient cellulose hydrolysis. The glucose stream produced using pretreated sugarcane bagasse was further converted into fructose syrup employing a packed bed reactor with immobilized glucose isomerase. The parameters involved in isomerization reaction were optimized and a high glucose conversion (48.9%) into fructose was achieved. Overall, the nanobiocatalyst-assisted valorization of pretreated sugarcane bagasse for producing a clean glucose stream and fructose syrup was established.
The concept of ‘nanobiocatalysis’ creates exciting opportunities for improving enzyme performance via immobilization onto nanomaterials. A nanobiocatalyst consisting of magnetic halloysite nanotube (MHNT)/α-amylase was evaluated to transform food processing waste into an active fermentation medium formulation for low-cost bioprocessing. A high loading of α-amylase (185.5 mg (g of support)−1) was achieved on the surface of MHNTs through polydopamine functionalization. We validated the establishment of an enzyme-support system retaining >89% catalytic activity (27332 IU (g of support)−1) with improved enzyme handling (>99.1% recovery) and reusability (>56% activity, 10 cycles). MHNTs remarkably improved the enzyme kinetics and thermodynamic characteristics along with operational and storage stabilities and mitigated the likely inhibitory effects of cellulose/metal ions as contaminants. In addition to facilitating a continuous production of reducing sugars from the extracted starch over 72 h, the nanobiocatalyst was equally effective in preparing a nutritive food waste hydrolysate as a fermentable medium substitute for batch culturing of E. coli and a single-cell protein (A. niger). The commercial relevance of waste hydrolysate was also investigated to promote calcite precipitation via Bacillus sp. induced biocementation. We evidenced that nanobiocatalyst-assisted “starch depolymerization” released more nutritional components into the hydrolysate suspension, easily accessible to growing microbial cultures.
Summarizing all, the natural abundance and low cost of support material (halloysite nanotubes), simple functionalization procedures, and excellent immobilization capability of our system warrants huge potential to be adopted for immobilizing other bio macromolecules beyond enzymes. The successful implementation of the current strategy at an industrial scale will also open new dimensions for transforming other agri-food wastes into biochemical products of commercial relevance
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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