Displaying publications 1 - 20 of 461 in total

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  1. Kamaraj M, Suresh Babu P, Shyamalagowri S, Pavithra MKS, Aravind J, Kim W, et al.
    J Environ Manage, 2024 Feb;351:119830.
    PMID: 38141340 DOI: 10.1016/j.jenvman.2023.119830
    Cyclodextrin (CD) and its derivatives are receiving attention as a new-generation adsorbent for water pollution treatment due to their external hydrophilic and internal hydrophobic properties. Among types of CD, β-Cyclodextrin (βCD) has been a material of choice with a proven track record for a range of utilities in distinct domains, owing to its unique cage-like structural conformations and inclusion complex-forming ability, especially to mitigate emerging contaminants (ECs). This article outlines βCD composites in developing approaches of their melds and composites for purposes such as membranes for removal of the ECs in aqueous setups have been explored with emphasis on recent trends. Electrospinning has bestowed an entirely different viewpoint on polymeric materials, comprising βCD, in the framework of diverse functions across a multitude of niches. Besides, this article especially discusses βCD polymer composite membrane-based removal of contaminants such as pharmaceutical substances, endocrine disruptors chemicals, and dyes. Finally, in this article, the challenges and future directions of βCD-based adsorbents are discussed, which may shed light on pragmatic commercial applications of βCD polymer composite membranes.
    Matched MeSH terms: Cellulose*
  2. Anne JM, Boon YH, Saad B, Miskam M, Yusoff MM, Shahriman MS, et al.
    R Soc Open Sci, 2018 Aug;5(8):180942.
    PMID: 30225083 DOI: 10.1098/rsos.180942
    In this work, we reported the synthesis, characterization and adsorption study of two β-cyclodextrin (βCD) cross-linked polymers using aromatic linker 2,4-toluene diisocyanate (2,4-TDI) and aliphatic linker 1,6-hexamethylene diisocyanate (1,6-HDI) to form insoluble βCD-TDI and βCD-HDI. The adsorption of 2,4-dinitrophenol (DNP) on both polymers as an adsorbent was studied in batch adsorption experiments. Both polymers were well characterized using various tools that include Fourier transform infrared spectroscopy, thermogravimetric analysis, Brunauer-Emmett-Teller analysis and scanning electron microscopy, and the results obtained were compared with the native βCD. The adsorption isotherm of 2,4-DNP onto polymers was studied. It showed that the Freundlich isotherm is a better fit for βCD-TDI, while the Langmuir isotherm is a better fit for βCD-HMDI. The pseudo-second-order kinetic model represented the adsorption process for both of the polymers. The thermodynamic study showed that βCD-TDI polymer was more favourable towards 2,4-DNP when compared with βCD-HDI polymer. Under optimized conditions, both βCD polymers were successfully applied on various environmental water samples for the removal of 2,4-DNP. βCD-TDI polymer showed enhanced sorption capacity and higher removal efficiency (greater than 80%) than βCD-HDI (greater than 70%) towards 2,4-DNP. The mechanism involved was discussed, and the effects of cross-linkers on βCD open up new perspectives for the removal of toxic contaminants from a body of water.
    Matched MeSH terms: Cellulose
  3. Shah SA, Sohail M, Minhas MU, Nisar-Ur-Rehman, Khan S, Hussain Z, et al.
    Drug Deliv Transl Res, 2019 04;9(2):555-577.
    PMID: 29450805 DOI: 10.1007/s13346-018-0486-8
    Cellulose acetate phthalate-based pH-responsive hydrogel was synthesized for fabrication of polymeric matrix tablets for gastro-protective delivery of loxoprofen sodium. Cellulose acetate phthalate (CAP) was cross-linked with methacrylic acid (MAA) using free radical polymerization technique. Fourier transform infrared (FTIR) spectra confirmed the formation of cross-linked structure of CAP-co-poly(methacrylic acid). Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) confirmed the thermal stability of polymeric networks, and scanning electron microscopy (SEM) and energy-dispersive X-ray spectrum (EDS) images unveiled that the prepared formulations were porous in nature and thus the developed formulations had shown better diffusibility. Swelling and in vitro drug release was performed at various pHs and maximum swelling and release was obtained at pH 7.4, while swelling and release rate was very low at pH 1.2 which confirmed the pH-responsive behavior of CAP-co-poly(MAA). CAP-co-poly(MAA) copolymer prevents the release of loxoprofen sodium into the stomach due to reduced swelling at gastric pH while showing significant swelling and drug release in the colon. Cytotoxicity studies revealed higher biocompatibility of fabricated hydrogel. Acute oral toxicity studies were performed for the evaluation and preliminary screening of safety profile of the developed hydrogels. Matrix tablets were evaluated for release behavior at simulated body pH. The investigations performed for analysis of hydrogels and fabricated matrix tablets indicated the controlled drug release and gastro-protective drug delivery of CAP-co-poly(MAA) hydrogels and pH-sensitive matrix tablets for targeted delivery of gastro-sensitive/irritative agents. Graphical abstract.
    Matched MeSH terms: Cellulose/administration & dosage; Cellulose/analogs & derivatives*; Cellulose/chemistry
  4. Lim SL, Ishak Ahmad, Azwan Mat Lazim
    Sains Malaysiana, 2015;44:779-785.
    The purpose of this study was to produce a novel pH sensitive hydrogel with superior thermal stability, composed of
    poly(acrylic acid) (PAA) and cellulose nanocrystal (CNC). CNC was extracted from kenaf fiber through a series of alkali
    and bleaching treatments followed by acid hydrolysis. PAA was then subjected to chemical cross-linking using the crosslinking
    agent (N,N-methylenebisacrylamide) in CNC suspension. The mixture was casted onto petri dish to obtain disc
    shape hydrogel. PAA/cellulose hydrogel with the same composition ratio were also prepared as control. The effect of
    reaction conditions such as the ratio of PAA and CNC on the swelling behavior of the hydrogel obtained towards pH
    was studied. The obtained hydrogel was further subjected to different tests such as thermogravimetric analysis (TGA) to
    study the thermal behavior, Fourier transform infrared for functional group identification and swelling test for swelling
    behavior at different pH. The cross-linking of PAA was verified with FTIR with the absence of C=C double bond. In TGA
    test, PAA/CNC hydrogel showed significantly higher thermal stability compared with pure PAA hydrogel. The hydrogel
    obtained showed excellent pH sensitivity and experienced maximum swelling at pH7. The PAA/CNC hydrogel can be
    developed further as drug carrier
    Matched MeSH terms: Cellulose
  5. Yasim-Anuar TAT, Ariffin H, Norrrahim MNF, Hassan MA, Andou Y, Tsukegi T, et al.
    Polymers (Basel), 2020 Apr 17;12(4).
    PMID: 32316664 DOI: 10.3390/polym12040927
    Two different liquid assisted processing methods: internal melt-blending (IMB) and twin-screw extrusion (TWS) were performed to fabricate polyethylene (PE)/cellulose nanofiber (CNF) nanocomposites. The nanocomposites consisted maleic anhydride-grafted PE (PEgMA) as a compatibilizer, with PE/PEgMA/CNF ratio of 97/3/0.5-5 (wt./wt./wt.), respectively. Morphological analysis exhibited that CNF was well-dispersed in nanocomposites prepared by liquid-assisted TWS. Meanwhile, a randomly oriented and agglomerated CNF was observed in the nanocomposites prepared by liquid-assisted IMB. The nanocomposites obtained from liquid-assisted TWS exhibited the best mechanical properties at 3 wt.% CNF addition with an increment in flexural strength by almost 139%, higher than that of liquid-assisted IMB. Results from this study indicated that liquid feeding of CNF assisted the homogenous dispersion of CNF in PE matrix, and the mechanical properties of the nanocomposites were affected by compounding method due to the CNF dispersion and alignment.
    Matched MeSH terms: Cellulose
  6. Abdalla A. Ab. Rashdi, Mohd Sapuan Salit, Khalina Abdan, Megat Mohamad Hamdan Megat
    MyJurnal
    Fibre reinforced composites have gained use in a variety of applications. The performances of these composites may suffer when the material is exposed to adverse environments for a long period of time. Kenaf fibre reinforced unsaturated polyester composites were subjected to water immersion tests in order to study the effects of water absorption on the mechanical properties. Composites specimens containing (10%, 20%, and 30%) weight percentages of fibre were prepared. Water absorption tests were conducted by immersing these specimens in a distilled water bath at 25oC for four months. The tensile properties of the specimens immersed in water were evaluated and compared with the dry composite specimens. A decrease in the tensile properties of the composites was demonstrated, indicating a great loss in the mechanical properties of the water-saturated samples compared to the dry samples. The percentage of moisture uptake was also increased as the percentage of the fibre weight increased due to the high cellulose content. The water absorption pattern of these composites was found to follow the Fickian behaviour.
    Matched MeSH terms: Cellulose
  7. Rahman ML, Wong ZJ, Sarjadi MS, Joseph CG, Arshad SE, Musta B, et al.
    Polymers (Basel), 2021 May 06;13(9).
    PMID: 34066308 DOI: 10.3390/polym13091486
    Toxic metals in the industrial wastewaters have been liable for drastic pollution hence a powerful and economical treatment technology is needed for water purification. For this reason, some pure cellulosic materials were derived from waste fiber to obtain an economical adsorbent for wastewater treatment. Conversion of cellulose into grafting materials such as poly(methyl acrylate)-grafted cellulose was performed by free radical grafting process. Consequently, poly(hydroxamic acid) ligand was produced from the grafted cellulose. The intermediate products and poly(hydroxamic acid) ligand were analyzed by FT-IR, FE-SEM, TEM, EDX, and XPS spectroscopy. The adsorption capacity (qe) of some toxic metals ions by the polymer ligand was found to be excellent, e.g., copper capacity (qe) was 346.7 mg·g-1 at pH 6. On the other hand, several metal ions such as cobalt chromium and nickel also demonstrated noteworthy sorption capacity at pH 6. The adsorption mechanism obeyed the pseudo second-order rate kinetic model due to the satisfactory correlated experimental sorption values (qe). Langmuir model isotherm study showed the significant correlation coefficient with all metal ions (R2 > 0.99), indicating that the single or monolayer adsorption was the dominant mode on the surface of the adsorbent. This polymer ligand showed good properties on reusability. The result shows that the adsorbent may be recycled for 6 cycles without any dropping of starting sorption capabilities. This polymeric ligand showed outstanding toxic metals removal magnitude, up to 90-99% of toxic metal ions can be removed from industrial wastewater.
    Matched MeSH terms: Cellulose
  8. Wsoo MA, Razak SIA, Bohari SPM, Shahir S, Salihu R, Kadir MRA, et al.
    Int J Biol Macromol, 2021 Jun 30;181:82-98.
    PMID: 33771547 DOI: 10.1016/j.ijbiomac.2021.03.108
    Vitamin D deficiency is now a global health problem; despite several drug delivery systems for carrying vitamin D due to low bioavailability and loss bioactivity. Developing a new drug delivery system to deliver vitamin D3 is a strong incentive in the current study. Hence, an implantable drug delivery system (IDDS) was developed from the electrospun cellulose acetate (CA) and ε-polycaprolactone (PCL) nanofibrous membrane, in which the core of implants consists of vitamin D3-loaded CA nanofiber (CAVD) and enclosed in a thin layer of the PCL membrane (CAVD/PCL). CA nanofibrous mat loaded with vitamin D3 at the concentrations of 6, 12, and 20% (w/w) of vitamin D3 were produced using electrospinning. The smooth and bead-free fibers with diameters ranged from 324 to 428 nm were obtained. The fiber diameters increased with an increase in vitamin D3 content. The controlled drug release profile was observed over 30-days, which fit with the zero-order model (R2 > 0.96) in the first stage. The mechanical properties of IDDS were improved. Young's modulus and tensile strength of CAVD/PCL (dry) were161 ± 14 and 13.07 ± 2.5 MPa, respectively. CA and PCL nanofibers are non-cytotoxic based on the results of the in-vitro cytotoxicity studies. This study can further broaden in-vivo study and provide a reference for developing a new IDDS to carry vitamin D3 in the future.
    Matched MeSH terms: Cellulose/analogs & derivatives*; Cellulose/chemistry
  9. Ling CX, Chang YP
    J Food Sci Technol, 2017 Jun;54(7):2041-2049.
    PMID: 28720961 DOI: 10.1007/s13197-017-2641-5
    Guava seeds are produced as a waste product by the guava processing industry. Their high carbohydrate contents may suit the carbohydrate needs of the feed sector but their high dietary fiber content limits their feed value. The feed values of fruit seeds can be improved through germination, which involves the mobilization of nutrients through seed enzymes and alters the seed carbohydrate composition. The changes of selected carbohydrates in guava (Psidium guajava L.) seeds brought by germination to those in red bean (Vigna angularis) and winter wheat (Triticum aestivum L.) were compared. The contents of soluble carbohydrates, digestible starch, resistant starch and cellulose in the seeds were determined. The radial diffusion method was used to detect carbohydrate-degrading enzymes in the seed extracts. Guava seeds were rich in cellulose (402.2 mg/g), which decreased progressively during germination, probably through the action of cellulase. Winter wheat contained the highest starch content (412.2 mg/g) and also distinct quantities of α-amylase and cellulase. The starch contents of all the seeds decreased, but the soluble carbohydrate contents in red beans and guava seeds increased significantly by the end of germination, suggesting the transient oversupply of reserve metabolites. The content of hydrolyzed polysaccharides increased in the germinated seeds with detectable amounts of cellulose-degrading enzymes present, indicating improved value as feed. Further research is warranted to explore the potential of guava seeds as a source of low-cost animal feed supplements.
    Matched MeSH terms: Cellulose
  10. As V, Kumar G, Dey N, Karunakaran R, K A, Patel AK, et al.
    Environ Res, 2023 Jan 01;216(Pt 2):114400.
    PMID: 36265604 DOI: 10.1016/j.envres.2022.114400
    Biowaste, produced from nature, is preferred to be a good source of carbon and ligninolytic machinery for many microorganisms. They are complex biopolymers composed of lignin, cellulose, and hemicellulose traces. This biomass can be depolymerized to its nano-dimensions to gain exceptional properties useful in the field of cosmetics, pharmaceuticals, high-strength materials, etc. Nano-sized biomass derivatives overcome the inherent drawbacks of the parent material and offer promises as a potential material for a wide range of applications with their unique traits such as low-toxicity, biocompatibility, biodegradability and environmentally friendly nature with versatility. This review focuses on the production of value-added products feasible from nanocellulose, nano lignin, and xylan nanoparticles which is quite a novel study of its kind. Dawn of nanotechnology has converted bio waste by-products (hemicellulose and lignin) into useful precursors for many commercial products. Nano-cellulose has been employed in the fields of electronics, cosmetics, drug delivery, scaffolds, fillers, packaging, and engineering structures. Xylan nanoparticles and nano lignin have numerous applications as stabilizers, additives, textiles, adhesives, emulsifiers, and prodrugs for many polyphenols with an encapsulation efficiency of 50%. This study will support the potential development of composites for emerging applications in all aspects of interest and open up novel paths for multifunctional biomaterials in nano-dimensions for cosmetic, drug carrier, and clinical applications.
    Matched MeSH terms: Cellulose/chemistry
  11. Dalle Vacche S, Karunakaran V, Patrucco A, Zoccola M, Douard L, Ronchetti S, et al.
    Molecules, 2021 Aug 04;26(16).
    PMID: 34443315 DOI: 10.3390/molecules26164723
    Nanocellulose was extracted from short bast fibers, from hemp (Cannabis sativa L.) plants harvested at seed maturity, non-retted, and mechanically decorticated in a defibering apparatus, giving non-aligned fibers. A chemical pretreatment with NaOH and HCl allowed the removal of most of the non-cellulosic components of the fibers. No bleaching was performed. The chemically pretreated fibers were then refined in a beater and treated with a cellulase enzyme, followed by mechanical defibrillation in an ultrafine friction grinder. The fibers were characterized by microscopy, infrared spectroscopy, thermogravimetric analysis and X-ray diffraction after each step of the process to understand the evolution of their morphology and composition. The obtained nanocellulose suspension was composed of short nanofibrils with widths of 5-12 nm, stacks of nanofibrils with widths of 20-200 nm, and some larger fibers. The crystallinity index was found to increase from 74% for the raw fibers to 80% for the nanocellulose. The nanocellulose retained a yellowish color, indicating the presence of some residual lignin. The properties of the nanopaper prepared with the hemp nanocellulose were similar to those of nanopapers prepared with wood pulp-derived rod-like nanofibrils.
    Matched MeSH terms: Cellulose/ultrastructure; Cellulose/chemistry*
  12. Safian MT, Sekeri SH, Yaqoob AA, Serrà A, Jamudin MD, Mohamad Ibrahim MN
    Talanta, 2022 Mar 01;239:123109.
    PMID: 34864531 DOI: 10.1016/j.talanta.2021.123109
    With each passing year, the agriculture and wood processing industries generate increasingly high tonnages of biomass waste, which instead of being burned or left to accumulate should be utilized more sustainably. In parallel, advances in green technology have encouraged large companies and nations to begin using eco-friendly materials, including eco-friendly emulsifiers, which are used in various industries and in bio-based materials. The emulsion-conducive properties of lignocellulosic materials such as cellulose, hemicellulose, and lignin, the building blocks of plant and wood structures, have demonstrated a particular ability to alter the landscape of emulsion technology. Beyond that, the further modification of their structure may improve emulsion stability, which often determines the performance of emulsions. Considering those trends, this review examines the performance of lignocellulosic materials after modification according to their stability, droplet size, and distribution by size, all of which suggest their outstanding potential as materials for emulsifying agents.
    Matched MeSH terms: Cellulose
  13. Thiagamani SMK, Nagarajan R, Jawaid M, Anumakonda V, Siengchin S
    Waste Manag, 2017 Nov;69:445-454.
    PMID: 28774586 DOI: 10.1016/j.wasman.2017.07.035
    As the annual production of the solid waste generable in the form of spent coffee bean powder (SCBP) is over 6 million tons, its utilization in the generation of green energy, waste water treatment and as a filler in biocomposites is desirable. The objective of this article is to analyze the possibilities to valorize coffee bean powder as a filler in cellulose matrix. Cellulose matrix was dissolved in the relatively safer aqueous solution mixture (8% LiOH and 15% Urea) precooled to -12.5°C. To the cellulose solution (SCBP) was added in 5-25wt% and the composite films were prepared by regeneration method using ethyl alcohol as a coagulant. Some SCBP was treated with aq. 5% NaOH and the composite films were also prepared using alkali treated SCBP as a filler. The films of composites were uniform with brown in color. The cellulose/SCBP films without and with alkali treated SCBP were characterized by FTIR, XRD, optical and polarized optical microscopy, thermogravimetric analysis (TGA) and tensile tests. The maximum tensile strength of the composite films with alkali treated SCBP varied between (106-149MPa) and increased with SCBP content when compared to the composites with untreated SCBP. The thermal stability of the composite was higher at elevated temperatures when alkali treated SCBP was used. Based on the improved tensile properties and photo resistivity, the cellulose/SCBP composite films with alkali treated SCBP may be considered for packaging and wrapping of flowers and vegetables.
    Matched MeSH terms: Cellulose/chemistry
  14. Mohd Zin NB, Mohamad Yusof B, Oslan SN, Wasoh H, Tan JS, Ariff AB, et al.
    AMB Express, 2017 Dec;7(1):131.
    PMID: 28651380 DOI: 10.1186/s13568-017-0433-y
    In recent years, many efforts have been directed to explore the methods to reduce the production costs of industrial lipase by improving the yield and the use of low-cost agricultural wastes. Coconut dregs, which is a lignocellulosic by-product from coconut oil and milk processing plants, is rich in cellulose (36%) and crude fat (9%). A newly isolated Bacillus stratosphericus has been demonstrated to perform cellulose hydrolysis on coconut dregs producing fermentable sugars. The highest extracellular lipase activity of 140 U/mL has been achieved in submerged fermentation with acid pre-treated coconut dregs. The lipase was found to be active over a wide range of temperatures and pHs. The activity of lipase can be generally increased by the presence of detergent ingredients such as Tween-80, cetyltrimethylammonium bromide, hydrogen peroxide and phosphate per sulphate. The great compatibility of lipase in commercial detergents has also underlined its potential as an additive ingredient in biodetergent formulations.
    Matched MeSH terms: Cellulose
  15. Kumar M, RaoT S, Isloor AM, Ibrahim GPS, Inamuddin, Ismail N, et al.
    Int J Biol Macromol, 2019 May 15;129:715-727.
    PMID: 30738161 DOI: 10.1016/j.ijbiomac.2019.02.017
    Cellulose acetate (CA) and cellulose acetate phthalate (CAP) were used as additives (1 wt%, 3 wt%, and 5 wt%) to prepare polyphenylsulfone (PPSU) hollow fiber membranes. Prepared hollow fiber membranes were characterized by surface morphology using scanning electron microscopy (SEM), surface roughness by atomic force microscopy (AFM), the surface charge of the membrane was analyzed by zeta potential measurement, hydrophilicity by contact angle measurement and the functional groups by fourier transform infrared spectroscopy (FTIR). Fouling resistant nature of the prepared hollow fiber membranes was evaluated by bovine serum albumin (BSA) and molecular weight cutoff was investigated using polyethylene glycol (PEG). By total organic carbon (TOC), the percentage rejection of PEG was found to be 14,489 Da. It was found that the hollow fiber membrane prepared by the addition of 5 wt% of CAP in PPSU confirmed increased arsenic removal from water as compared to hollow fiber membrane prepared by 5 wt% of CA in PPSU. The removal percentages of arsenic with CA-5 and CAP-5 hollow fiber membrane was 34% and 41% with arsenic removal permeability was 44.42 L/m2h bar and 40.11 L/m2h bar respectively. The increased pure water permeability for CA-5 and CAP-5 hollow fiber membrane was 61.47 L/m2h bar and 69.60 L/m2 h bar, respectively.
    Matched MeSH terms: Cellulose/analogs & derivatives*; Cellulose/chemistry
  16. Peh KK, Lim CP, Quek SS, Khoh KH
    Pharm Res, 2000 Nov;17(11):1384-8.
    PMID: 11205731
    PURPOSE: To use artificial neural networks for predicting dissolution profiles of matrix-controlled release theophylline pellet preparation, and to evaluate the network performance by comparing the predicted dissolution profiles with those obtained from physical experiments using similarity factor.

    METHODS: The Multi-Layered Perceptron (MLP) neural network was used to predict the dissolution profiles of theophylline pellets containing different ratios of microcrystalline cellulose (MCC) and glyceryl monostearate (GMS). The concepts of leave-one-out as well as a time-point by time-point estimation basis were used to predict the rate of drug release for each matrix ratio. All the data were used for training, except for one set which was selected to compare with the predicted output. The closeness between the predicted and the reference dissolution profiles was investigated using similarity factor (f2).

    RESULTS: The f2 values were all above 60, indicating that the predicted dissolution profiles were closely similar to the dissolution profiles obtained from physical experiments.

    CONCLUSION: The MLP network could be used as a model for predicting the dissolution profiles of matrix-controlled release theophylline pellet preparation in product development.

    Matched MeSH terms: Cellulose/chemistry
  17. Lie-Injo Luan Eng, Weitkamp LR, Kosasih EN, Bolton JM, Moore CL
    Hum. Hered., 1971;21(4):376-83.
    PMID: 5003129
    Matched MeSH terms: Cellulose
  18. Sun Q, Chen WJ, Pang B, Sun Z, Lam SS, Sonne C, et al.
    Bioresour Technol, 2021 Dec;341:125807.
    PMID: 34474237 DOI: 10.1016/j.biortech.2021.125807
    In recent years, visualization and characterization of lignocellulose at different scales elucidate the modifications of its ultrastructural and chemical features during hydrothermal pretreatment which include degradation and dissolving of hemicelluloses, swelling and partial hydrolysis of cellulose, melting and redepositing a part of lignin in the surface. As a result, cell walls are swollen, deformed and de-laminated from the adjacent layer, lead to a range of revealed droplets that appear on and within cell walls. Moreover, the certain extent morphological changes significantly promote the downstream processing steps, especially for enzymatic hydrolysis and anaerobic fermentation to bioethanol by increasing the contact area with enzymes. However, the formation of pseudo-lignin hinders the accessibility of cellulase to cellulose, which decreases the efficiency of enzymatic hydrolysis. This review is intended to bridge the gap between the microstructure studies and value-added applications of lignocellulose while inspiring more research prospects to enhance the hydrothermal pretreatment process.
    Matched MeSH terms: Cellulose*
  19. Sulaiman AZ, Ajit A, Chisti Y
    Biotechnol Prog, 2013 Nov-Dec;29(6):1448-57.
    PMID: 23926080 DOI: 10.1002/btpr.1786
    A recombinant Trichoderma reesei cellulase was used for the ultrasound-mediated hydrolysis of soluble carboxymethyl cellulose (CMC) and insoluble cellulose of various particle sizes. The hydrolysis was carried out at low intensity sonication (2.4-11.8 W cm(-2) sonication power at the tip of the sonotrode) using 10, 20, and 40% duty cycles. [A duty cycle of 10%, for example, was obtained by sonicating for 1 s followed by a rest period (no sonication) of 9 s.] The reaction pH and temperature were always 4.8 and 50°C, respectively. In all cases, sonication enhanced the rate of hydrolysis relative to nonsonicated controls. The hydrolysis of CMC was characterized by Michaelis-Menten kinetics. The Michaelis-Menten parameter of the maximum reaction rate Vmax was enhanced by sonication relative to controls, but the value of the saturation constant Km was reduced. The optimal sonication conditions were found to be a 10% duty cycle and a power intensity of 11.8 W cm(-2) . Under these conditions, the maximum rate of hydrolysis of soluble CMC was nearly double relative to control. In the hydrolysis of cellulose, an increasing particle size reduced the rate of hydrolysis. At any fixed particle size, sonication at a 10% duty cycle and 11.8 W cm(-2) power intensity improved the rate of hydrolysis relative to control. Under the above mentioned optimal sonication conditions, the enzyme lost about 20% of its initial activity in 20 min. Sonication was useful in accelerating the enzyme catalyzed saccharification of cellulose.
    Matched MeSH terms: Carboxymethylcellulose Sodium/chemistry*; Cellulose/chemistry*
  20. Chin DWK, Lim S, Pang YL, Lim CH, Lee KM
    Bioresour Technol, 2019 Nov;292:121967.
    PMID: 31450064 DOI: 10.1016/j.biortech.2019.121967
    Ethylene glycol in the presence of sodium hydroxide was utilised as pretreatment for effective delignification and reduced the recalcitrance of lignocellulosic biomass which ramified the exposure of cellulose. Two-staged acid hydrolysis was also investigated which demonstrated its synergistic efficiency by minimising the deficiency of single stage acid hydrolysis. The operating parameters including acid concentration, temperature, residence time and cellulose loading for two-staged acid hydrolysis were studied by using ethylene glycol delignified degraded oil palm empty fruit bunch (DEFB) to recover the sugar based substrates for potential biofuels and other bio-chemicals production. In this study, stage I 45 wt% acid at 65 °C for 30 min coupled with high cellulose loading 21.25 w/v% and 12 wt% acid at 100 °C for 120 min was able to release a total of 89.8% optimum sugar yield with minimal formation of degradation products including 0.058 g/L furfural, 0.0251 g/L hydroxymethylfurfural and 0.200 g/L phenolic compounds.
    Matched MeSH terms: Cellulose
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