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1.
Pulps obtained from the ethanol/water cooking of sugarcane bagasse were bleached with the xylanase enzyme obtained from the
fungus Thermomyces lanuginosus IOC-4145 and with the commercial enzyme Cartazyme HS from Sandoz. By changing the enzyme dose from 4.3 to 36 IU/g of pulp,
kappa number and viscosity were maintained when the xylanase from T. lanuginosus was used. On the other hand, by using Cartazyme HS, kappa number decreased by 17%, reaching 35.5. This pulp was further extracted
with NaOH without a decrease in viscosity (10 cP), and pulp with a kappa number of 13 was obtained. Xylanases had no significant
effect on the ethanol/water pulps. 相似文献
2.
Sugarcane bagasse Acetosolv pulps were bleached by xylanase and the pulps classified by using Fourier transform infrared (FTIR)
spectroscopy and principal component analysis (PCA). Pulp was treated with xylanase for 4–8 h with stirring at 30°C. Some
samples were further extracted with NaOH for 1 h at 65°C. FTIR spectra were recorded directly from the dried pulp samples
by using the diffuse reflectance technique. Reduction in kappa number of 69% was obtained after sequence xylanase (4 h)-alkaline
extraction. During bleaching the viscosity decreased only 12%. FTIR-PCA showed that the first three principal components (PCs)
explained more than 90% of the total variance of the pulp spectra. PC2×PC1 plot showed that the points related to pulps from
sequence xylanase (4 h)-alkaline extraction are different from the other. This group isenlarged by plotting PC3×PC1 or PC3×PC2
containing all pulps submitted to alkaline extraction. PC2 and PC3 are the principal factor for differentiation of the pulps.
These PCs suffer influence of the ester bands (1740 and 1244 cm−1). On the other hand, the pulps bleached only with xylanase could not be differentiated from the nonbleached pulps. 相似文献
3.
Luís R. M. Oliveira Regina Y. Moriya Adilson R. Gonçalves 《Applied biochemistry and biotechnology》2006,129(1-3):326-333
In this work, pretreatment-enzymatic series of the bagasse-sugarcane pulp and alkaline extraction of enzyme treated pulp were
carried out. In the pretreatment an enzyme dose was utilized and acetosolv pulp suspension of 3% (w/v) with different solvents
(distilled water, 0.05 mol/L acetate buffer pH 5.5 and 0.05 mol/L phosphate buffer pH 7.25) stirred at 85 rpm for 2 or 4 h.
The enzymes used were pulpzyme and cartazyme, both commercial. The accompaniment of the enzymatic activity was carried out
through measurement in initial and finish of each enzymatic pretreatment. The xylanase-treated pulps and xylanase-alkaline-extracted
pulps were analyzed regarding kappa number and viscosity. Pulpzyme recovery was better in phosphate buffered medium (84, 46,
and 23% for first, second, and third enzymatic treatment, respectively) although in aqueous medium reached only 2% for every
treatments. However, the improvement of pulp properties was evidenced only in aqueous medium for pulpzyme. Cartazyme recovery
was similar for both solvents (water and acetate buffer), reaching values around 19% for first enzymatic treatment and 9%
for second one. Nevertheless, the pulp properties increased only in acetate buffered medium. 相似文献
4.
Gonçalves Adilson R. Costa Sirlene M. Esposito Elisa 《Applied biochemistry and biotechnology》2002,98(1-9):373-382
Three strains of the white-rot fungus Panus tigrinus (FTPT-4741, FTPT-4742, and FTPT-4745) were cultivated on sugarcane bagasse prior to kraft pulping. Pulp yields, kappa number,
and viscosity of all pulps were determined and Fourier transform infrared (FTIR) spectra from the samples were recorded. The
growth of P. tigrinus strains in plastic bags increased the manganese peroxide and xylanase activities. Lignin peroxidase was not detected in the
three systems (shaken and nonshaken flasks and plastic bags). FTIR spectra were reduced to their principal components, and
a clear separation between FTPT-4742 and the control was observed. Strain FTPT-4745 decayed lignin more selectively in the
three systems utilized. Yields of kraft pulping were low, ranging from 20 to 45% for the plastic bag samples and from 12 to
38% for the flask samples. Kappa numbers were 1–18 and viscosity ranged from 2.3 to 6.8 cP. 相似文献
5.
Effect of pre‐treatment of sugarcane bagasse on the cellulose solution and application for the cellulose hydrogel films 下载免费PDF全文
Sugarcane bagasse was used as a cellulose resource, and the transparent cellulose hydrogel films were obtained from the purified cellulose by phase inversion process without chemical cross‐linking, when the dissolved cellulose in lithium chloride/N,N‐dimethyl acetamide was transformed into the solid film. On these processes, bagasse was pre‐treated by 10 wt% sodium hydroxide in the absence and presence of bleaching of 10 vol% sodium hypochlorite (NaOCl) solution in order to obtain cellulose fibers. Here, the bleaching temperature was varied from 40 to 50°C. The effect of pre‐treatment conditions on the resultant cellulose solution and hydrogel films was investigated. It was seen that strong bleaching removed most of lignin component from the bagasse. However, viscosity and size exclusion chromatogram of the cellulose indicated that this operation decreased average molecular weight of the cellulose fibers from 2.1 × 106 to 4.8 × 105. These property changes of fibers also caused increase of water content and weakening of mechanical strength of the resultant hydrogels. In addition, scanning probe microscopy in wet state revealed that the porous fiber network structure in the hydrogel was greatly influenced by bleaching with NaOCl. The average pore size of fiber network was decreased from 8.1 to 5.9 nm as the NaOCl treatment was at 50°C, because of expanded fibers in the swollen hydrogel. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
6.
Mônica Caramez Triches Damaso Aline Machado de Castro Raquel Machado Castro Carolina Maria M. C. Andrade Nei Pereira Jr. 《Applied biochemistry and biotechnology》2004,115(1-3):1003-1012
Xylanases have significant current and potential uses for several industries including paper and pulp, food, and biofuel.
For the biofuel industry, xylanases can be used to aid in the conversion of lignocellulose to fermentable sugars (e.g., xylose).
We investigated the thermophilic fungus Thermomyces lanuginosus was yielded for xylanase production and found that the highest activity (850 U/mL) was yielded after 96 h of semisolid fermentation.
The enzyme was used for hydrolyzing agricultural residues with and without pretreatment. Such residues were characterized
in relation to the maximum xylose content by total acid hydrolysis. The highest xylose yields realized by enzymatic hydrolysis
were 24 and 52%, achieved by using 3000 U/g (dried material) of sugarcane bagasse and corncob, respectively, which received
both alkali and thermal pretreatment. 相似文献
7.
Regina Y. Moriya Adilson R. Gonçalves Fabrícia P. Faria 《Applied biochemistry and biotechnology》2005,121(1-3):195-203
Organosolv (ethanol/water and acetosolv) pulps were treated with Humicola grisea var. thermoidea and compared with Cartazyme HS xylanase-treated pulp. The ethanol/water pulps treated with H. grisea had the same viscosity as unbleached pulps (8 cP). Ethanol/water pulps treated with Cartazyme had higher viscosity than H. grisea-treated pulps (12 cP). Acetosolv pulps treated with H. grisea and Cartazyme presented a reduction in viscosity; however, the pulps treated with H. grisea had a lower reduction in viscosity than Cartazyme-treated pulps. Ethanol/water pulps treated with H. grisea had a 23% reduction in kappa number in 4 and 8 h of treatment, compared with the unbleached pulps. Cartazyme-treated pulps
had a kappa number similar to that of the control pulps for 4 h of treatment. Extending the treatment time to 12 h resulted
in a reduction of 33%. The acetosolv pulp treated with H. grisea had a kappa number reduced to 23% in 4 h. Cartazyme treatment resulted in a reduction of 55 and 44% in kappa number for 4
and 8 h of treatment, respectively, when compared with control pulp. Extending the treatment time to 12 h decreased the kappa
number 72%. Fourier transform infrared spectra and principal component analysis showed differences among unbleached, H. grisea-treated, and Cartazyme-treated pulps. 相似文献
8.
Rafael Fogel Rafaela Rodrigues Garcia Rebeca da Silva Oliveira Denise Neves Menchero Palacio Luciana da Silva Madeira Nei Pereira Jr. 《Applied biochemistry and biotechnology》2005,122(1-3):741-752
The dilute-acid hydrolysis of sugarcane bagasse was optimized using a statistical experimental design resulting in hydrolysates
containing 57.25 g/L of xylose, which were fermented with a high inoculum concentration (10 g/L of the yeast Candida guilliermondii IM/UFRJ 50088). The addition of urea reduced the time of conversion (t
C) to 75 h (without nitrogen source addition t
C>127 h), and, consequently, improving the rates of xylitol bioproduction. Fermentator experiments, using the optimized conditions,
resulted in enhanced conversion rates, reducing t
C to 30 h. The stability of the yeast in the hydrolysate was also verified in a 480-h cultivation. 相似文献
9.
Lime pretreatment of crop residues bagasse and wheat straw 总被引:9,自引:0,他引:9
Vincent S. Chang Murlidhar Nagwani Mark T. Holtzapple 《Applied biochemistry and biotechnology》1998,74(3):135-159
Lime (calcium hydroxide) was used as a pretreatment agent to enhance the enzymatic digestibility of two common crop residues:
bagasse and wheat straw. A systematic study of pretreatment conditions suggested that for short pretreatment times (1–3 h),
high temperatures (85-135°C) were required to achieve high sugar yields, whereas for long pretreatment times (e.g., 24 h),
low temperatures (50–65°C) were effective. The recommended lime loading is 0.1 g Ca(OH)2/g dry biomass. Water loading had little effect on the digestibility. Under the recommended conditions, the 3-d reducing sugar
yield of the pretreated bagasse increased from 153 to 659 mg Eq glucose/g dry biomass, and that of the pretreated wheat straw
increased from 65 to 650 mg Eq glucose/g dry biomass. A material balance study on bagasse showed that the biomass yield after
lime pretreatment is 93.6%. No glucan or xylan was removed from bagasse by the pretreatment, whereas 14% of lignin became
solubilized. A lime recovery study showed that 86% of added calcium was removed from the pretreated bagasse by ten washings
and could be recovered by carbonating the wash water with CO2 at pH 9.5. 相似文献
10.
Martínez Ernesto Acosta Silva Silvio S. Felipe Maria G. A. 《Applied biochemistry and biotechnology》2000,84(1-9):633-641
The effect of the oxygen transfer coefficient on the production of xylitol by biocon version of xylose present in sugarcane
bagasse hemicellulosic hydrolysate using the yeast Candiada guilliermondii was investigated. Continuous cultivation was carried out in a 1.25-L fermentor at 30°C, pH 5.5, 300 rpm, and a dilution rate
of 0.03/h, using oxygen transfer coefficients of 10,20, and 30/h. The results showed that the microbial xylitol production
(11 g/L) increased by 108% with the decrease in the oxygen volumetric transfer coefficient from 30 to 20/h. The maximum values
of xylitol productivity (0.7g/[L…h]) and yield (0.58 g/g) were obtained at k
L
a 20/h. 相似文献
11.
Alves Lourdes A. Vitolo Michele Felipe Maria das Graças A. de Almeida e Silva João Batista 《Applied biochemistry and biotechnology》2002,98(1-9):403-413
The sugarcane bagasse hydrolysate, which is rich in xylose, can be used as culture medium for Candida guilliermondii in xylitol production. However, the hydrolysate obtained from bagasse by acid hydrolysis at 120°C for 20 min has by-products
(acetic acid and furfural, among others), which are toxic to the yeast over certain concentrations. So, the hydrolysate must
be pretreated before using in fermentation. The pretreatment variables considered were: adsorption time (15,37.5, and 60 min),
type of acid used (H2So4 and H3Po4), hydrolysate concentration (original, twofold, and fourfold. concentrated), and active
charcoal (0.5, 1.75 and 3.0%). The suitability of the pretreatment was followed by measuring the xylose reductase (XR) and
xylitol dehydrogenase (XD) activity of yeast grown in each treated hydrolysate. The response surface methodology (24 full factorial design with a centered face) indicated that the hydrolysate might be concentrated fourfold and the pH adjusted
to 7.0 with CaO, followed by reduction to 5.5 with H3PO4. After that it was treated with active charcoal (3.0%) by 60 min. This pretreated hydrolysate attained the high XR/XD ratio
of 4.5. 相似文献
12.
Heizir F. de Castro Samuel C. Oliveira Sandra A. Furlan 《Applied biochemistry and biotechnology》2003,107(1-3):547-555
A new approach for the utilization of hemicellulosic hydrolysate from sugarcane bagasse is described. This approach consists
of using the hydrolysate to dilute the conventional feedstock (sugarcane juice) to the usual sugar concentration (150 g/L)
employed for the industrial production of ethanol. The resulting sugar mixture was used as the substrate to evaluate the performance
of a continuous reactor incorporating a cell recycle module, operated at several dilution rates. An induced flocculent pentose-fermenting
yeast strain was used for this bioconversion. Under the conditions used, the reactor performance was satisfactory at substrate
feed rates of 30 g/(L·h) or less, corresponding to an ethanol productivity of about 11.0 g/(L·h) and an overall sugar conversion
>95%. These results show real advantages over the existing alternatives for a better exploitation of surplus bagasse to increase
industrial alcohol production. 相似文献
13.
Bagasse, corn husk, and switchgrass were pretreated with ammonia water to enhance enzymatic hydrolysis. The sample (2 g) was
mixed with 1–6 mL ammonia water (25–28% ammonia) and autoclaved at 120°C for 20 min. After treatment, the product was vacuum-dried
to remove ammonia gas. The dried solid could be used immediately in the enzymatic hydrolysis without washing. The enzymatic
hydrolysis was effectively improved with more than 0.5 and 1 mL ammonia water/g for corn husk and bagasse, respectively. In
bagasse, glucose, xylose, and xylobiose were the main products. The adsorption of CMCase and xylanase was related to the initial
rate of enzymatic hydrolysis. In corn husks, arabinoxylan extracted by pretreatment was substantially unhydrolyzed because
of the high ratio of arabinose to xylose (0.6). The carbohydrate yields from cellulose and hemicellulose were 72.9% and 82.4%
in bagasse, and 86.2% and 91.9% in corn husk, respectively. The ammonia/water pretreatment also benefited from switchgrass
(Miscanthus sinensis and Solidago altissima L.) hydrolysis. 相似文献
14.
Débora Danielle Virgínio da Silva Maria das Graças de Almeida Felipe Ismael Maciel de Mancilha Sílvio Silvério da Silva 《Applied biochemistry and biotechnology》2005,121(1-3):427-437
The effect of glucose on xylose-xylitol metabolism in fermentation medium consisting of sugarcane bagasse hydrolysate was
evaluated by employing an inoculum of Candida guilliermondii grown in synthetic media containing, as carbon sources, glucose (30 g/L), xylose (30 g/L), or a mixture of glucose (2 g/L)
and xylose (30 g/L). The inoculum medium containing glucose promoted a 2.5-fold increase in xylose reductase activity (0.582
IU/mgprot) and a 2-fold increase in xylitol dehydrogenase activity (0.203 IU/mgprot) when compared with an inoculum-grown medium containing only xylose. The improvement in enzyme activities resulted in higher
values of xylitol yield (0.56 g/g) and productivity (0.46 g/[L·h]) after 48 h of fermentation. 相似文献
15.
M. Kathiresan P. Sivaraj 《International Journal of Polymer Analysis and Characterization》2016,21(5):428-435
The present work includes the processing and characterization of nano-based natural reinforcement for polymer composite materials. Sugarcane bagasse has been collected and the fibers were extracted using manual striping process. Undesirable materials present in the extracted fibers were removed by 1% NaOH-based chemical treatment. The macrofibers were reduced to nano scale by using high-energy ball milling process. Nanoparticles from bagasse fibers were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The degree of crystallinity of nano bagasse is 55.2% and it was reported by using XRD. A FTIR spectrum confirms the presence of cellulose functional groups in nano bagasse. The nano bagasse dimensions and morphology were investigated using SEM. The average length and diameter of the nano bagasse is 51.2 and 46.1 nm, respectively. Thermal stability of the nano bagasse was revealed by TGA analysis. The chemical composition of cellulose, lignin, and hemicellulose contents was also investigated. 相似文献
16.
This work introduces the feasibility of using sugar cane bagasse (SCB) – a sugar cane industry waste – as a selective solid phase extractor for Fe(III). The order of metal uptake capacities in μmol g?1 for the extraction of six tested metal ions from aqueous solution using static technique is Fe(III) > Cu(II) > Pb(II) > Zn(II) > Cd(II) > Co(II). Since SCB exhibits remarkable binding characteristics for Fe(III), special interest was devoted for optimizing its uptake and studying its selectivity properties under static and dynamic conditions. In this respect, batch experiments were carried out at the pH range 1.0–4.0, initial concentration of metal ion (10–100 μmol), weight of phase (25, 50, 75, 100, 125 and 150 mg) and shaking time (10, 30, 45, 60, 90, 120 and 150 min). FT-IR spectra of SCB before and after uptake of Fe(III) were recorded to explore the nature of the functional groups responsible for binding of Fe(III) onto the studied natural biosorbent. The equilibrium data were better fitted with Langmuir model (r2 = 0.985) than Freundlich model (r2 = 0.934). Moreover, Fe(III) sorption was fast and completed within 60 min. The adsorption kinetics data were best fitted with the pseudo-second-order type. As a view to find a suitable application of SCB based on its unique property as a benign sorbent, it was found that, Fe(III) spiked natural water samples such as doubly distilled water (DDW), drinking tap water (DTW), natural drinking water (NDW), ground water (GW) and Nile River water (NRW) was quantitatively recovered (>95.0%) using batch and column experiments, with no matrix interferences. 相似文献
17.
Sene Luciane Felipe Maria G. A. Silva Silvio S. Vitolo Michele 《Applied biochemistry and biotechnology》2001,91(1-9):671-680
Candida guilliermondii FTI 20037 was cultured in sugarcane bagasse hydrolysate supplemented with 2.0 g/L of (NH4)2SO4, 0.1 g/L of CaCl2·2H2O, and 20.0 g/L of rice bran at 35°C; pH 4.0; agitation of 300 rpm; and aeration of 0.4, 0.6, or 0.8 vvm. The high xylitol
production (20.0 g/L) and xylose reductase (XR) activity (658.8 U/mg of protein) occurred at an aeration of 0.4 vvm. Under
this condition, the xylitol dehydrogenase (XD) activity was low. The apparent K
M for XR and XD against substrates and cofactors were as follows: for XR, 6.4×10−2
M (xylose) and 9.5×10−3 mM (NADPH); for XD, 1.6×10−1
M (xylitol) and 9.9×10−2 mM (NAD+). Because XR requires about 10-fold less xylose and cofactor than XD for the condition in which the reaction rate is
half of the V
max, some interference on the overall xylitol production by the yeast could be expected. 相似文献
18.
In biodegradation studies with isotope-labelled pesticides, fractions of non-extractable residues (NER) remain, but their nature and composition is rarely known, leading to uncertainty about their risk. Microbial growth leads to incorporation of carbon into the microbial mass, resulting in biogenic NER. Formation of microbial mass can be estimated from the microbial growth yield, but experimental data is rare. Instead, we suggest using prediction methods for the theoretical yield based on thermodynamics. Recently, we presented the Microbial Turnover to Biomass (MTB) method that needs a minimum of input data. We have estimated the growth yield of 40 organic chemicals (31 pesticides) using the MTB and two existing methods. The results were compared to experimental values, and the sensitivity of the methods was assessed. The MTB method performed best for pesticides. Having the theoretical yield and using the released CO2 as a measure for microbial activity, we predicted a range for the formation of biogenic NER. For the majority of the pesticides, a considerable fraction of the NER was estimated to be biogenic. This novel approach provides a theoretical foundation applicable to the evaluation and prediction of biogenic NER formation during pesticide degradation experiments, and may also be employed for the interpretation of NER data from regulatory studies. 相似文献