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1.
Cellulose extraction of Alstonia scholaris: A comparative study on efficiency of different bleaching reagents for its isolation and characterization.
Rizwan, M, Gilani, SR, Durrani, AI, Naseem, S
International journal of biological macromolecules. 2021;:964-972
Abstract
The incredible benefits of Alstonia scholaris are piquing researchers' attention in extracting its cellulose and utilizing it in further therapeutic applications. This study is based on cellulose extraction from its stalks and processed through chemical pre-treatments to manifest its cellulose content by using different bleaching reagents. A comparison was made on efficiencies of three reagents and it is found that the hydrogen peroxide exposed maximum cellulose than sodium hypochlorite and sodium chlorite. The experimental results revealed that A. scholaris possess 68-70% cellulose content. FTIR spectrum shows that OH- and CH- vibrations of cellulose appeared at 3320 cm-1 & 2892 cm-1 respectively whereas SEM images show fibrillation, rough surface, and lumens in bleached fiber that attributes to the removal of lignin and hemicelluloses and confirms cellulose extraction. The XRD pattern certifies the crystalline nature and compactness of cellulose whereas tensile properties and TGA help in understanding its flexibility, mechanical strength, and thermal stability at 370 °C respectively.
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2.
Preparation of alpha cellulose from sugarcane bagasse and its cationization: Synthesis, characterization, validation and application as wet-end additive.
Rana, V, Malik, S, Joshi, G, Rajput, NK, Gupta, PK
International journal of biological macromolecules. 2021;:793-809
Abstract
Paper industry uses cationic polymers for imparting strong bonds with pulp furnish to enhance strength properties. Due to environmental reasons, emphasis is on utilization of biobased polymers in place of synthetic. Sugarcane bagasse, an agro-industrial waste, was processed for extraction of alpha cellulose and preparation of cationic derivative. Reaction conditions were optimized to achieve highly substituted cationic derivative with insertion of 2-hydroxy-3-(trimethylammonium) propyl group. Artificial neural network (ANN) was applied to analyze the experimental data for cationization modeling. Maximum degree of substitution 0.66, was achieved at 5.0 M NaOH/anhydro glucose unit (AGU), 20 °C alkalization temperature, 8 min alkalization time, 3.5 M/AGU etherification agent concentration, 45 min time and 60 °C etherification reaction temperature. The experimental results showed that mean square error values for input parameters were significantly low. The ANN based regression values of the output, and computed values of target were close to unity. ANN based fitting indicates better performance level to predict the degree of substitution. The synthesized cationic cellulose was characterized through FTIR, XRD, NMR, FESEM and TGA. The activity of cationized cellulose as wet-end additive was tested for bagasse, wheat straw and recycled pulps due to their shorten fiber and feeble pulp characters than wood pulp.
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3.
Electrospinning of Electroconductive Water-Resistant Nanofibers of PEDOT-PSS, Cellulose Nanofibrils and PEO: Fabrication, Characterization, and Cytocompatibility.
Latonen, RM, Cabrera, JAW, Lund, S, Kosourov, S, Vajravel, S, Boeva, Z, Wang, X, Xu, C, Allahverdiyeva, Y
ACS applied bio materials. 2021;(1):483-493
Abstract
Electrically conductive composite nanofibers were fabricated using poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT-PSS) and cellulose nanofibrils (CNFs) via the electrospinning technique. Poly(ethylene oxide) (PEO) was used to assist the electrospinning process, and poly(ethylene glycol) diglycidyl ether was used to induce chemical cross-linking, enabling stability of the formed fibrous mats in water. The experimental parameters regarding the electrospinning polymer dispersion and electrospinning process were carefully studied to achieve a reproducible method to obtain bead-free nanofibrous mats with high stability after water contact, with an electrical conductivity of 13 ± 5 S m-1, thus making them suitable for bioelectrochemical applications. The morphology of the electrospun nanofibers was characterized by scanning electron microscopy, and the C/S ratio was determined with energy dispersive X-ray analysis. Cyclic voltammetric studies showed that the PEDOT-PSS/CNF/PEO composite fibers exhibited high electroactivity and high stability in water for at least two months. By infrared spectroscopy, the slightly modified fiber morphology after water contact was demonstrated to be due to dissolution of some part of the PEO in the fiber structure. The biocompatibility of the PEDOT-PSS/CNF/PEO composite fibers when used as an electroconductive substrate to immobilize microalgae and cyanobacteria in a photosynthetic bioelectrochemical cell was also demonstrated.
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4.
Bile acid sequestrants: a review of mechanism and design.
Feng, Y, Li, Q, Ou, G, Yang, M, Du, L
The Journal of pharmacy and pharmacology. 2021;(7):855-861
Abstract
OBJECTIVE Bile acid sequestrants (BAS) are used extensively in the treatment of hypercholesterolaemia. This brief review aimed to describe the design and evaluation of three types of BAS: amphiphilic copolymers, cyclodextrin/poly-cyclodextrin and molecular imprinted polymers. The mechanisms underlying the action of BAS are also discussed. KEY FINDINGS BAS could lower plasma cholesterol, improve glycemic control in patients with type 2 diabetes and regulate balance energy metabolism via receptors or receptor-independent mediated mechanisms. Different types of BAS have different levels of ability to bind to bile acids, different stability and different in-vivo activity. CONCLUSIONS A growing amount of evidence suggests that bile acids play important roles not only in lipid metabolism but also in glucose metabolism. The higher selectivity, specificity, stability and in-vivo activity of BAS show considerable potential for lipid-lowering therapy.
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5.
Nano-cellulose reinforced starch bio composite films- A review on green composites.
Bangar, SP, Whiteside, WS
International journal of biological macromolecules. 2021;:849-860
Abstract
Plastic-based food packaging is generating a serious environmental problem by accumulating large amounts of plastic in the surroundings. Ecological and health concerns are driving research efforts for developing biodegradable films. There are few alternatives that could reduce the environmental impact; one of them is to substitute petroleum-based plastic with starch-based film. Starch has remarkable properties, including biodegradability, sustainability, abundancy, and capable of being modified or blended with other polymers. However, low mechanical strength and low water resistance restrict its application in food packaging. Nanocellulose isolated from lignocellulosic fibers has attracted tremendous interest in the field of science due to high crystallinity and mechanical strength, unique morphology along with abundancy, renewability, and biodegradability. Therefore, nano cellulose as a reinforcer proved to be a good option for fabricating biocomposites for food packaging. The current review will give a critical snapshot of the potential application of nanocellulose in food packaging and discuss new challenges and opportunities for starch biocomposites enriched with nano cellulose.
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6.
Cellulose nanocrystal/low methoxyl pectin gels produced by internal ionotropic gelation.
Abitbol, T, Mijlkovic, A, Malafronte, L, Stevanic, JS, Larsson, PT, Lopez-Sanchez, P
Carbohydrate polymers. 2021;:117345
Abstract
The biotechnological applications of cellulose nanocrystals (CNCs) continue to grow due to their sustainable nature, impressive mechanical, rheological, and emulsifying properties, upscaled production capacity, and compatibility with other materials, such as protein and polysaccharides. In this study, hydrogels from CNCs and pectin, a plant cell wall polysaccharide broadly used in food and pharma, were produced by calcium ion-mediated internal ionotropic gelation (IG). In the absence of pectin, a minimum of 4 wt% CNC was needed to produce self-supporting gels by internal IG, whereas the addition of pectin at 0.5 wt% enabled hydrogel formation at CNC contents as low as 0.5 wt%. Experimental data indicate that CNCs and pectin interact to give robust and self-supporting hydrogels at solid contents below 2.5 %. Potential applications of these gels could be as carriers for controlled release, scaffolds for cell growth, or wherever else distinct and porous network morphologies are required.
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7.
Cello-oligosaccharides production from lignocellulosic biomass and their emerging prebiotic applications.
Ávila, PF, Silva, MF, Martins, M, Goldbeck, R
World journal of microbiology & biotechnology. 2021;(5):73
Abstract
Cello-oligosaccharides (COS) are linear oligosaccharides composed of β-1,4-linked glucopyranose units. They comprise a group of important new oligosaccharides of significant interest and potential applications in the pharmaceutical, food, chemical, and feed industries, currently emerging as potential prebiotic compounds. COS from lignocellulosic biomass, specifically the agro-industrial residues and by-products of the forestry industry, constitute a new attractive process that imposes the sustainable use of biomass resources. Two main strategies have been used for the production of COS: acid-based and enzyme-based cellulose hydrolysis. The latter has been considered more attractive due to the use of milder reaction conditions and less production of monomers. This review summarizes that although COS is emerging as a potential prebiotic with also other potential applications, there is a lack of information regarding the large-scale production, which could be associated with the recalcitrant nature of cellulose compared to other polysaccharides, which hinders the hydrolysis of its dense network.
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8.
Synthesis and characterization of cellulose/TiO2 nanocomposite: Evaluation of in vitro antibacterial and in silico molecular docking studies.
M V, A, Harb, M, Sundaram, R
Carbohydrate polymers. 2020;:116868
Abstract
Cellulose/TiO2 nanocomposite was synthesized using coagulation in sodium hydroxide-thiourea-urea aqueous solution medium by precipitation method. This method was accomplished green and cost-effective for the fabrication of composite nanomaterials. Structure, morphology and optical properties of the nanocomposite were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and ultraviolet diffuse reflectance spectra respectively. XRD results showed the anatase structure of TiO2 while FESEM micrograph showed evidence of particle size ranging from 20 to 40 nm for cellulose/TiO2 nanocomposite. The Fourier transfer infrared spectroscopy investigation reveals that the TiO2 is bound to hydroxyl groups to the cellulose by hydrogen bonding. The optical energy bandgap is found to be 2.71 eV for nanocomposite from the UV-DRS. The mechanical strength of the composites gently escalated with the addition of TiO2 nanoparticles into cellulose polymer matrix. Cellulose/TiO2 nanocomposite was screened for their in vitro antibacterial activity against Staphylococcus aureus and Escherichia coli bacteria have been investigated. Additionally, the results obtained from in silico molecular docking studies confirm the interaction of nanocomposite with proteins, were in good agreement with the experimental data. This finding provides a novel and simple method for the synthesis of cellulose/TiO2 nanocomposite as functional biomaterials.
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9.
The Effects of Irvingia gabonensis Seed Extract Supplementation on Anthropometric and Cardiovascular Outcomes: A Systematic Review and Meta-Analysis.
Lee, J, Chung, M, Fu, Z, Choi, J, Lee, HJ
Journal of the American College of Nutrition. 2020;(5):388-396
Abstract
Background: It has been hypothesized that Irvingia gabonensis can promote weight loss by increasing fatty acid breakdown and inhibiting fatty acid synthesis.Objective: We conducted a systematic review and meta-analysis to evaluate the efficacy and safety of Irvingia gabonensis seed extract supplementation on weight-related health outcomes.Methods: Literature searches were conducted in 4 databases from January 2018 to identify randomized controlled trials (RCTs) investigating the effects of Irvingia gabonensis seed extract supplementation on anthropometric measures and cardiovascular biomarkers. Two investigators independently performed abstract screenings, full-text screenings, data extraction, and risk of bias (ROB) assessments. Random effects meta-analyses were performed when 3 or more RCTs reported the same outcome.Results: Five RCTs met the eligibility criteria for this systematic review. Four of the 5 RCTs were rated as having a high ROB, and only one RCT was rated as having a low ROB. Random-effects meta-analysis of the 5 RCTs showed that a significant decrease in body weight, body fat, and waist circumference was observed in relation to Irvingia gabonensis seed extract supplementation. However, the only one low-ROB trial did not have significantly different outcomes. Meta-analysis also showed beneficial effects of Irvingia gabonensis seed extract supplementation on total cholesterol, LDL-cholesterol, HDL-cholesterol, and triglycerides. Only the low-ROB trial showed a trend of increasing HDL-cholesterol levels (net percent change = 11.61%; 95% confidence interval (CI: -6.12%, 29.34%) and decreasing triglyceride levels (net percent change = -29%; 95% CI: -76%, 19%). The reported adverse events were minor in these 5 RCTs.Conclusions: Overall efficacy of Irvingia gabonensis seed extract supplementation on weight loss seems positive but is limited due to poor methodological quality and the insufficient reporting of the clinical trials. Further high quality RCTs are needed to determine the effectiveness of Irvingia gabonensis seed extract supplement on the weight-related health outcomes.
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10.
Combined pretreatment of sugarcane bagasse using alkali and ionic liquid to increase hemicellulose content and xylanase production.
Rashid, R, Ejaz, U, Ali, FI, Hashmi, IA, Bari, A, Liu, J, Wang, L, Fu, P, Sohail, M
BMC biotechnology. 2020;(1):64
Abstract
BACKGROUND Lignin in sugarcane bagasse (SB) hinders its utilization by microorganism, therefore, pretreatment methods are employed to make fermentable components accessible to the microbes. Multivariate analysis of different chemical pretreatment methods can aid to select the most appropriate strategy to valorize a particular biomass. RESULTS Amongst methods tested, the pretreatment by using sodium hydroxide in combination with methyltrioctylammonium chloride, an ionic liquid, (NaOH+IL) was the most significant for xylanase production by Bacillus aestuarii UE25. Investigation of optimal levels of five significant variables by adopting Box-Behnken design (BBD) predicted 20 IU mL- 1 of xylanase and experimentally, a titer of 17.77 IU mL- 1 was obtained which indicated the validity of the model. The production kinetics showed that volumetric productivity of xylanase was much higher after 24 h (833.33 IU L- 1 h- 1) than after 48 h (567.08 IU L- 1 h- 1). The extracted xylan from SB induced more xylanase in the fermentation medium than pretreated SB or commercially purified xylan. Nuclear Magnetic Resonance, Fourier transform infrared spectroscopy and scanning electron microscopy of SB indicated removal of lignin and changes in the structure of SB after NaOH+IL pretreatment and fermentation. CONCLUSION Combined pretreatment of SB with alkali and methyltrioctylammonium chloride appeared better than other chemical methods for bacterial xylanase production and for the extraction of xylan form SB.