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1.
Biomacromolecules ; 2024 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-38958474

RESUMEN

The pursuit of renewable and eco-friendly raw materials for biobased materials is a growing field. This study utilized ellagitannin and cellulose microfibrils derived from rambutan peel waste alongside gelatin to develop eco-conscious hydrogels. The cellulose/gelatin hydrogels were formulated in two weight ratios (0.5:1 to 1:1), and the influence of gelatin on the chemical composition and rheology was studied. Composite hydrogels, functionalized with an ellagitannin-rich extract, exhibited a remarkable enhancement of up to 14-fold in compressive strength. The hydrogels also demonstrated antimicrobial properties, reducing the Staphylococcus aureus colony count within 24 h. The hydrogel, derived from rambutan peel waste, is biocompatible and could potentially be explored for biomedical applications such as drug delivery systems, and wound dressings. This suggests that it might offer significant value for sustainable materials science, although specific applications have yet to be tested.

2.
Int J Biol Macromol ; 259(Pt 2): 128857, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38143063

RESUMEN

This study assesses the viability of an accelerated solvent extraction technique employing environmentally friendly solvents to extract ellagitannins while producing cellulose-rich fibers from rambutan peel. Two sequential extraction protocols were investigated: 1) water followed by acetone/water (4:1, v:v), and 2) acetone followed by acetone/water (4:1, v:v), both performed at 50 °C. The first protocol had a higher extraction yield of 51 %, and the obtained extractives featured a higher total phenolic (531.4 ± 22.0 mg-GAE/g) and flavonoid (487.3 ± 16.9 mg-QE/g) than the second protocol (495.4 ± 32.8 mg-GAE/g and 310.6 ± 31.4 mg-QE/g, respectively). The remaining extractive-free fibers were processed by bleaching using either 2 wt% sodium hydroxide with 3 wt% hydrogen peroxide or 4-5 wt% peracetic acid. Considering bleaching efficiency, yield, and process sustainability, the single bleaching treatment with 5 wt% of peracetic acid was selected as the most promising approach to yield cellulose-rich fibers. The samples were analyzed by methanolysis to determine the amount and type of poly- and oligosaccharides and studied by 13C solid-state nuclear magnetic resonance spectroscopy and thermal gravimetric analysis. The products obtained from the peels demonstrate significant potential for use in various sectors, including food, nutraceuticals, cosmetics, and paper production.


Asunto(s)
Celulosa , Sapindaceae , Celulosa/análisis , Acetona , Taninos Hidrolizables , Sapindaceae/química , Ácido Peracético , Solventes/química , Frutas/química , Agua/análisis
3.
ACS Omega ; 8(45): 43295-43303, 2023 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-38024664

RESUMEN

The search for environmentally friendly and sustainable sources of raw materials has been ongoing for quite a while, and currently, the utilization and applications of agro-industrial biomass residues in biomedicine are being researched. In this study, a polydopamine (PDA)-modified bacterial cellulose (BC) and hydroxyapatite (HA) composite scaffold was fabricated using the freeze-drying method. The as-prepared hydroxyapatite was synthesized via the chemical precipitation method using sugarcane filter cake as a calcium source, as reported in a previous study. X-ray diffraction analysis revealed a carbonated phase of the prepared hydroxyapatite, similar to that of the natural bone mineral. Wide-angle X-ray scattering analysis revealed the successful fabrication of BC/HA composite scaffolds, while X-ray photoelectron spectroscopy suggested that PDA was deposited on the surface of the BC/HA composite scaffolds. In vitro cell viability assays indicated that BC/HA and PDA-modified composite scaffolds did not induce cytotoxicity and were biocompatible with MC3T3-E1 preosteoblasts. PDA-modified composite scaffolds showed enhanced protein adsorption capacity in vitro compared to the unmodified scaffolds. On a concluding note, these results demonstrate that agro-industrial biomass residues have the potential to be used in biomedical applications and that PDA-modified BC/HA composite scaffolds are a promising biomaterial for bone tissue engineering.

4.
ACS Omega ; 8(34): 31100-31111, 2023 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-37663459

RESUMEN

Microcrystalline cellulose (MCC) has gained considerable attention as a functional ingredient in bread making. This work demonstrates the isolation of MCC from sugar cane bagasse (SCB) for preparing bread. The effect of MCC on bread attributes and antioxidant activity by impregnation with sappan wood extract (SAP) was evaluated. The highest crystallinity index and suitable size of MCC were achieved at 85 °C under 90 min hydrolysis condition. Increasing MCC/SAP levels in bread showed a significant increase in bread color with decreases in the specific volume and baking loss. There was a positive correlation between bread texture and the MCC/SAP level. The addition of MCC/SAP interfered with the bread hardness. Low MCC/SAP levels have no effect on springiness and cohesiveness; however, 4% MCC/SAP has significantly decreased these attributes, with the highest antioxidant activity and phenolic content. Therefore, MCC can be functionalized with SAP as an antioxidant fiber additive for health benefits in bakery products.

5.
Polymers (Basel) ; 15(15)2023 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-37571218

RESUMEN

Textile waste has emerged as a critical global challenge, with improper disposal practices leading to adverse environmental consequences. In response to this pressing issue, there is growing interest in recycling textile waste containing cellulose as an alternative approach to reducing the impact of industrial waste on the environment. The objective of this research is to investigate the extraction and characterization of nanocellulose from polyester-cotton textile waste as a potential solution to address the growing concerns of waste management in the textile industry. To obtain nanocellulose, a comprehensive process involving alkaline sodium hydroxide (NaOH) treatment of the polyester-cotton textile (35% PET and 65% cotton) was employed, resulting in average yield percentages ranging from 62.14% to 71.21%. To achieve the complete hydrolysis of PET polyester in the blends, second hydrolysis was employed, and the optimized condition yield cotton fiber was 65.06 wt%, relatively close to the theoretical yield. Subsequently, the obtained cellulosic material underwent an acid hydrolysis process using 70 percent (v/v) sulfuric acid (H2SO4) solution at 45 °C for 90 min, resulting in nanocellulose. Centrifugation at 15,000 rpm for 15 min facilitated the separation of nanocellulose from the acid solution and yielded 56.26 wt% at optimized conditions. The characterization of the nanocellulose was carried out utilizing a comprehensive array of techniques, including absorption, transmission, and reflection spectra, and Fourier transform infrared. The characterization results provide valuable insights into the unique properties of nanocellulose extracted from textile waste. In this research, the obtained nanocellulose was mixed with PVA and silver nanoparticle to form biodegradable film composites as the reinforcement. In comparison, biodegradable film of PVA:nanocellulose 9.5:0.5 with silver nanoparticle 0.3 wt% and glycerol as a plasticizer exhibits better tensile strength (2.37 MPa) and elongation (214.26%) than the PVA film with normal cellulose. The prepared biodegradable film was homogeneous and had a smooth surface without the internal defect confirmed by the CT scan. This result opens avenues for enhancing the quantities of eco-friendly film composites, potentially replacing conventional plastic films in the future.

6.
Int J Biomater ; 2023: 9630168, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37485045

RESUMEN

In this study, nanocomposite film was fabricated using cellulose nanocrystals (CNCs) as nanofiller in a polymer matrix of polyvinyl alcohol (PVA) and gum tragacanth (GT) via solution casting. CNCs were extracted from sugarcane bagasse using a steam explosion technique followed by acid hydrolysis. Initial analysis of CNCs by transmission electron microscopy (TEM) showed nanosized particles of 104 nm in length and 7 nm in width. Physical and chemical characteristics of neat PVA, PVA/GT, and PVA/GT/CNC films with varying concentrations of CNCs (from 2% to 10%) were analyzed by the scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectrometry, mechanical test, and swelling test. The SEM analysis showed cluster formation of CNCs in the polymer matrix at high concentration. The developed films were transparent. FTIR spectrometry analysis confirmed the chemical functional groups of the various components in the film. The presence of GT and CNCs in the polymer matrix improved the characteristics of films as evident in the prolonged stability for 7 days and increased mechanical properties. The highest elastic modulus of 1526.11 ± 31.86 MPa and tensile strength of 80.39 MPa were recorded in PVA/GT/CNC2 film. The swelling ability, however, decreased from 260% to 230%. Cytotoxicity analysis of the PVA/GT/CNC film showed that it is nontoxic to mouse fibroblast cells L929 with 95% cell viability. Films loaded with betel leaf extract exhibited excellent antibacterial activities against Staphylococcus aureus DMST 8840 and Pseudomonas aeruginosa TISTR 781 with 28.20 ± 0.84 mm and 23.60 ± 0.55 mm inhibition zones, respectively. These results demonstrate that PVA/GT/CNC loaded with the betel leaf extract could act as promising and versatile wound dressings to protect the wound surface from infection and dehydration.

7.
Biomolecules ; 13(7)2023 07 20.
Artículo en Inglés | MEDLINE | ID: mdl-37509191

RESUMEN

Superoxide dismutase (SOD) is an essential enzyme that eliminates harmful reactive oxygen species (ROS) generating inside living cells. Due to its efficacities, SOD is widely applied in many applications. In this study, the purification of SOD produced from Saccharomyces cerevisiae TBRC657 was conducted to obtain the purified SOD that exhibited specific activity of 513.74 U/mg with a purification factor of 10.36-fold. The inhibitory test revealed that the purified SOD was classified as Mn-SOD with an estimated molecular weight of 25 kDa on SDS-PAGE. After investigating the biochemical characterization, the purified SOD exhibited optimal activity under conditions of pH 7.0 and 35 °C, which are suitable for various applications. The stability test showed that the purified SOD rapidly decreased in activity under high temperatures. To overcome this, SOD was successfully immobilized on bacterial cellulose (BC), resulting in enhanced stability under those conditions. The immobilized SOD was investigated for its ability to eliminate ROS in fibroblasts. The results indicated that the immobilized SOD released and retained its function to regulate the ROS level inside the cells. Thus, the immobilized SOD on BC could be a promising candidate for application in many industries that require antioxidant functionality under operating conditions.


Asunto(s)
Saccharomyces cerevisiae , Superóxido Dismutasa , Saccharomyces cerevisiae/metabolismo , Especies Reactivas de Oxígeno , Superóxido Dismutasa/metabolismo , Estrés Oxidativo , Fibroblastos/metabolismo
8.
Int J Biol Macromol ; 234: 123676, 2023 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-36796561

RESUMEN

The goal of this study is to isolate cellulose nanocrystals (CNC) from sugarcane leaves (SCL) and fabricate filter membranes. Filter membranes consisting of the CNC and varying amount graphene oxide (GO) were fabricated using vacuum filtration technique. The α-cellulose content increased from 53.56 ± 0.49 % in untreated SCL to 78.44 ± 0.56 % and 84.99 ± 0.44 % in steam-exploded and bleached fibers, respectively. Atomic force microscopy (AFM) and transmission electron microscope (TEM) of CNC isolated from SCL indicated nanosized particles in the range of 7.3 nm and 150 nm for diameter and length, respectively. Morphologies of the fiber and CNC/GO membranes were determined by scanning electron microscopy (SEM) and crystallinity by X-ray diffraction (XRD) analysis of crystal lattice. The crystallinity index of CNC decreased with the addition of GO into the membranes. The CNC/GO-2 recorded the highest tensile index of 3.001 MPa. The removal efficiency increases with increasing GO content. The highest removal efficiency of 98.08 % was recorded for CNC/GO-2. CNC/GO-2 membrane reduced growth of Escherichia coli to 65 CFU compared to >300 CFU of control sample. SCL is a potential bioresource for isolation of cellulose nanocrystals and fabrication of high-efficiency filter membrane for particulate matter removal and inhibition of bacteria.


Asunto(s)
Nanopartículas , Saccharum , Celulosa/química , Material Particulado , Nanopartículas/química
9.
ACS Omega ; 7(44): 39975-39984, 2022 Nov 08.
Artículo en Inglés | MEDLINE | ID: mdl-36385815

RESUMEN

Agroindustrial wastes are renewable sources and the most promising sustainable alternative to lignocellulosic biomass for cellulose production. This study assessed the electrothermal pretreatment of rambutan peel (RP) for producing cellulose fibers. The pretreatment was carried out by Ohmic heating at a solid-to-liquid ratio of 1:10 (w/v) in a water/ethanol (1:1, v/v) mixture as the electrical transmission medium at 60 ± 1 °C for different holding times (15, 30, and 60 min). Ohmic heating did not significantly influence the total fiber yield for the various holding times. However, the compositions of the samples in terms of extractives, lignin, hemicellulose, and α-cellulose content were significantly influenced. In addition, the electrothermal pretreatment method reduced the bleaching time of RP by 25%. The pretreated fibers were thermally stable up to 240 °C. Ohmic heating pretreatment times of 15 and 30 min were found most promising, reducing the required bleaching chemicals and increasing the α-cellulose yield. The pretreated bleached cellulose fibers had similar properties to nontreated bleached fibers and could be efficiently processed into stable gels of strong shear-thinning behavior with potential application as rheology modifiers in food products. Our results demonstrate that rambutan peel could serve as a promising sustainable alternative to woody biomass for cellulose production. Ohmic heating meets the requirements for industrial applications as it is eco-friendly, improves the efficiency and energy consumption in fiber processing, and could as well be included in the processing of similar food wastes.

10.
ACS Omega ; 7(38): 34647-34656, 2022 Sep 27.
Artículo en Inglés | MEDLINE | ID: mdl-36188307

RESUMEN

This study extracted ellagitannins from rambutan peel using the Soxhlet technique. The extract was further partitioned and fractionated to get extract rich in ellagitannin and geraniin, respectively. The partitioning of the extract significantly increased total phenolic content (TPC) by 36.3% and its biological properties. Mineral elements such as Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, and Zn were identified in both peel and extract. Ellagitannins such as geraniin and corilagin with metabolites (gallic acid and ellagic acid) were identified as the major compounds. Analysis of antioxidant activities shows that the ellagitannin rich extract is as powerful as vitamin C. Geraniin was the main contributor to the free radical scavenging activity. The study also revealed that extract with a fraction rich in geraniin has antioxidant activity equivalent to commercial geraniin (1.56 ± 0.11 Trolox equivalent g/g). It also showed low cytotoxicity on fibroblast L929 cells, moderate tyrosinase activity, and good efficacy against Staphylococcus aureus, Staphylococcus epidermidis, and Cutibacterium acnes strains. Successive fractionation of the extract is a promising technique to produce geraniin rich fractions with enhanced antioxidant property. Rambutan peel, as a natural product, is a good source of mineral elements and biologically active compounds for pharmaceutical, nutraceutical, and cosmetic formulations.

11.
Cellulose (Lond) ; 29(11): 6205-6218, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35693912

RESUMEN

Abstract: Particulate matter (PM) pollution and SARS-CoV-2 (COVID-19) have brought severe threats to public health. High level of PM serves as a carrier of COVID-19 which is a global pandemic. This study fabricated filter membrane for face mask using bacterial cellulose and fingerroot extract (BC-FT) via immersion technique. The surface area, pore volume and pore size of BC were analyzed by Brunauer-Emmett-Teller. The physiochemical properties of the membrane were analyzed by scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffractometer. The crystallinity decreased from 63.7% in pure BC to 52.4% in BC-FT filter membrane. Young's modulus increased from 1277.02 MPa in pure BC to 2251.17 MPa in BC-FT filter membrane. The filter membrane showed excellent PM 0.1 removal efficiency of 99.83% and antimicrobial activity against Staphylococcus aureus and Escherichia coli. The fabricated membrane is excellent to prevent inhalation of PM2.5 and COVID-19 respiratory droplet. Supplementary information: The online version contains supplementary material available at 10.1007/s10570-022-04641-3.

12.
ACS Omega ; 7(16): 13455-13464, 2022 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-35559199

RESUMEN

This study investigated the effect of ultrasound-assisted hydrogen peroxide (H2O2) pretreatment on sugar cane bagasse (SCB) followed by Monascus purpureus TISTR 3003 cultivation for lovastatin production under solid-state fermentation (SSF). Optimization of the pretreatment conditions was investigated using a response surface methodology (RSM). Within the range of the selected operating conditions, the optimized values of H2O2 concentration, amplitude, SCB dosage, and sonication time were found to be 2.74%, 83.22 µm, 2.84% and 52.29 min, respectively. The R 2 value of 0.9749 indicated that the fitted model is in good agreement with the predicted and actual lovastatin production. On the basis of the optimum conditions, the lovastatin production was 2347.10 ± 17.19 µg/g, which is 2.4 times higher than that under untreated conditions. Scanning electron microscopy (SEM) analysis explored the surface structure of the untreated SCB, which showed a compact rigid structure. In contrast, treated SCB had a rough surface structure and cracks as a result of the pretreatment.

13.
Sci Total Environ ; 835: 155281, 2022 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-35439514

RESUMEN

Sugarcane bagasse (SCB) is an abundant by-product from sugar production and promising biomass for cellulose extraction. Simulated elephant colon pretreatment (SEP) to reduce chemical use in cellulose extraction from SCB was investigated using elephant dung as fermentation inoculum. The 16S rRNA gene sequences showed microorganisms in elephant dung that corresponded to metabolites during pretreatment. Organic acid accumulation in the fermentation broth was confirmed by the presence of lactic, acetic, propionic and butyric acids. Lignin peroxidase, manganese peroxidase and xylanase detected during the pretreatment enhanced lignin removal. The SEP fiber showed increased cellulose content, while lignin content decreased with reduced bleaching time from 7 to 5 h and high whiteness and crystallinity indices. Lignin removal was also confirmed by Fourier transform infrared spectroscopy. Scanning electron microscopy revealed increasing internal surface area through opening up the fiber structure. SEP offered an efficient and promising approach for cellulose fiber extraction with reduced use of chemicals for the bleaching process.


Asunto(s)
Elefantes , Saccharum , Animales , Carbohidratos , Celulosa/química , Colon/metabolismo , Elefantes/metabolismo , Hidrólisis , Lignina/metabolismo , ARN Ribosómico 16S , Saccharum/química
14.
Food Chem ; 382: 132332, 2022 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-35134722

RESUMEN

This study employed the principles of electrothermal process using ohmic heating (OH) to extract phenolic compounds from rambutan peel. Deionized water and ethanol at different concentrations (50% and 70%) were used as electrical-transmission medium at different holding times (15, 30 and 60 min). The result showed significant difference (p ≤ 0.05) between the water and ethanol-based extracts in terms of yield, total phenolic, flavonoid contents and antioxidant activities. The main compounds such as gallic acid, corilagin, geraniin and ellagic acid were identified in the peel. Bread fortified with the extract showed better phenolic content and antioxidant activities, with 15 µg/mL fortification level having excellent texture properties. Interestingly, fortified breads showed excellent antifungal activity, thereby extended the shelf life of the bread crumb. The efficient ohmic heating extraction technique and proper formulation of rambutan peel extract in food, could serves as vital approach for high-quality products development with longer shelf life.


Asunto(s)
Sapindaceae , Antifúngicos , Antioxidantes/farmacología , Pan , Calefacción , Extractos Vegetales/farmacología
15.
J Colloid Interface Sci ; 611: 491-502, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-34973654

RESUMEN

Hydroxyapatite (HA), an inorganic compound, plays an essential role in the proliferation and differentiation of bone cells. Using cellulose nanocrystals (CNCs) as green dispersants to improve homogenization of HA is promising in the fabrication of nanocomposite scaffolds with biocompatibility for bone tissue engineering. The HA/CNC (HC) nanoparticle suspension was incorporated in polyvinyl alcohol (PVA)-based scaffold to investigate the physical and chemical properties. The PVA/HC composites demonstrated high porous structure and swelling ability for cell attachment and a 3-fold improvement in compressive modulus compared with free HC scaffold. Moreover, the presence of HC nanoparticles has promoted the proliferation and mineralization of pre-osteoblast. Our findings could provide an effective strategy by using bio-dispersants to incorporate mineral elements into synthetic polymers for the fabrication of functional tissue engineering scaffolds.


Asunto(s)
Durapatita , Osteoblastos , Materiales Biocompatibles , Diferenciación Celular , Proliferación Celular , Ingeniería de Tejidos , Andamios del Tejido
16.
Int J Biol Macromol ; 191: 299-304, 2021 Nov 30.
Artículo en Inglés | MEDLINE | ID: mdl-34530037

RESUMEN

Nanocellulose derived from microorganism is crucial bio-based products due to its unique physicochemical and mechanical properties for material science. Thus, optimizing bacterial cellulose (BNC) production is essential to widen applications and reduce production cost. Using various carbon sources derive from fruits as alternatives for synthesizing BNC could produce a low-cost BNC with comparable properties. Although Komagataeibacter xylinus grown in different natural juices, including clarified juice (CJ), sugarcane juice (SC) and coconut juice (CN) demonstrated a lower yield than that of control medium (HS), FTIR confirmed no change in chemical functional groups of BNCs. Similarly, different sugar sources have slightly effects on mechanical and thermal properties of BNC. However, the internal morphology illustrated the pore structure in oval shape for HS and CN while CJ and SC resulted in irregular pores which could lead to the highest crystallinity index value for BNC from HS compared to that from alternative media.


Asunto(s)
Acetobacteraceae/metabolismo , Celulosa/biosíntesis , Microbiología Industrial/métodos , Azúcares/metabolismo , Carbono/metabolismo , Cocos/química , Frutas/química , Nanoestructuras/química , Nanoestructuras/microbiología , Saccharum/química
17.
Polymers (Basel) ; 13(11)2021 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-34071613

RESUMEN

Nanocomposite film of poly(vinyl alcohol) (PVA) incorporated with bacterial cellulose nanocrystals (BCNCs) and magnetite nanoparticles (Fe3O4) is reported in this study. The BCNC-Fe3O4 nanoparticles and PVA film was prepared by in situ synthesis technique using chemical co-precipitation. Different concentrations of BCNC-Fe3O4 (20%, 40% and 60% w/w) were mechanically dispersed in PVA solution to form the nanocomposite film. Transmission electron microscopy (TEM) analysis of BCNC-Fe3O4 nanoparticles showed irregular particle sizes ranging from 4.93 to 30.44 nm with an average size distribution of 22.94 nm. The presence of characteristic functional groups of PVA, BCNC and Fe3O4 were confirmed by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis. Scanning electron microscope (SEM) attached energy dispersive spectroscopy (EDS) and vibrating sample magnetometer (VSM) analysis revealed that, the iron content and magnetic property increased with increasing BCNC-Fe3O4 content. The saturation magnetizations (MS) value increased from 5.14 to 11.56 emu/g. The PVA/ BCNC-Fe3O4 at 60% showed the highest Young's modulus value of 2.35 ± 0.16 GPa. The prepared film could be a promising polymeric nanomaterial for various magnetic-based applications and for the design of smart electronic devices.

18.
ACS Omega ; 5(43): 28168-28177, 2020 Nov 03.
Artículo en Inglés | MEDLINE | ID: mdl-33163799

RESUMEN

In this study, cellulose was obtained from sugarcane bagasse (SCB) and treated with xylanase to remove residual noncellulosic polymers (hemicellulose and lignin) to improve its dyeability. The cellulose fibers were dyed with natural dye solutions extracted from the heart wood of Ceasalpinia sappan Linn. and Artocarpus heterophyllus Lam. Fourier-transform infrared (FTIR) spectroscopy, Raman analysis, and whiteness index (WI) indicated successful extraction of cellulose by eliminating hemicellulose and lignin. The FTIR analysis of the dyed fibers confirmed successful interaction between natural dyes and cellulose fibers. The absorption (K) and scattering (S) coefficient (K/S) values of the dyed fibers increased in cellulose treated with xylanase before dyeing. Scanning electron microscopy (SEM) analysis showed that the surface of alkaline-bleached fibers (AB-fibers) was smoother than alkaline-bleached xylanase fibers (ABX-fibers), and the presence of dye particles on the surface of dyed fibers was confirmed by energy-dispersive spectrometry (EDS) analysis. The X-ray diffraction (XRD) revealed a higher crystallinity index (CrI), and thermal gravimetric analysis (TGA) also presented higher thermal stability in the dyed fibers with good colorfastness to light. Therefore, xylanase treatment and natural dyes can enhance dyeability and improve the properties of cellulose for various industrial applications.

19.
Bioresour Technol ; 284: 391-397, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-30959376

RESUMEN

Production of high-titer sugar from lignocellulose is important in terms of process economics of bio-based product industry. In this study, to obtain high titers and yields of sugars, we combined pretreatment and saccharification steps, both at high solids loadings. First, pretreatment of oak was optimized at a 30% (w/w) solids loading. The whole slurry of the pretreated oak was subjected to a fed-batch saccharification step at the final solids loading of 30%, to minimize loss of fermentable sugars and simplify the processes. As a result, high-titer sugars (157.5 g/L) consisting of 120.2 g/L of glucose and 37.3 g/L of xylose were obtained at 75.9% and 58.6%, respectively, of theoretical maximum yields, based on the initial glucan and xylan contents. Thus, through proper optimization processes of oak, the combination of pretreatment and saccharification at high solids loadings was effective in obtaining both high titers and high yields of sugars from lignocellulose.


Asunto(s)
Glucosa/metabolismo , Quercus/metabolismo , Xilosa/metabolismo , Fermentación , Glucanos/metabolismo , Hidrólisis , Lignina/metabolismo , Xilanos/metabolismo
20.
Carbohydr Polym ; 205: 159-166, 2019 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-30446091

RESUMEN

Bacterial nanocellulose/hydroxyapatite/cellulose nanocrystal (BHC) composites were synthesized via in-situ synthesis using cellulose nanocrystals (CNCs) to improve colloidal stability and the dispersion of hydroxyapatite (HA) during the bacterial nanocellulose (BNC) cultivation period. Transmission electron microscopy images and energy dispersive spectroscopy (EDS) results confirmed the dispersion of HA on the CNC particles with a Ca/P ratio of 1.66 corresponding to that of the stoichiometric HA. The SEM images and EDS results showed that the integration of the HA and BNC network without CNC assistance (BHA (0.25 and 0.5 wt.%) composites) was less than that for BHC at both concentrations. Fourier-transform infrared analysis, XRD and thermal degradation revealed the effect of HA on the BHC composites with a decreased CrI% and improved thermal property. Cytotoxicity proved the potential for using BHC composites for bone tissue engineering scaffold with cell viability up to 83.4 ± 3.6% compared to the negative control (99.2 ± 0.08%).


Asunto(s)
Celulosa/química , Durapatita/química , Nanopartículas/química , Polisacáridos Bacterianos/química , Animales , Materiales Biocompatibles/síntesis química , Materiales Biocompatibles/química , Materiales Biocompatibles/toxicidad , Celulosa/síntesis química , Celulosa/toxicidad , Durapatita/síntesis química , Durapatita/toxicidad , Fibroblastos/efectos de los fármacos , Gluconacetobacter xylinus/química , Ratones , Nanopartículas/toxicidad , Polisacáridos Bacterianos/síntesis química , Polisacáridos Bacterianos/toxicidad , Temperatura , Andamios del Tejido/química
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