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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
2.
Simultaneous saccharification and extractive fermentation of lignocellulosic materials into lactic acid was investigated using
a two-zone bioreactor. The system is composed of an immobilized cell reactor, a separate column reactor containing the lignocellulosic
substrate and a hollow-fiber membrane. It is operated by recirculating the cell free enzyme (cellulase) solution from the
immobilized cell reactor to the column reactor through the membrane. The enzyme and microbial reactions thus occur at separate
locations, yet simultaneously. This design provides flexibility in reactor operation as it allows easy separation of the solid
substrate from the microorganism, in situ removal of the product and, if desired, different temperatures in the two reactor sections. This reactor system was tested
using pretreated switchgrass as the substrate. It was operated under a fed-batch mode with continuous removal of lactic acid
by solvent extraction. The overall lactic acid yield obtainable from this bioreactor system is 77% of the theoretical. 相似文献
3.
Pretreatment of switchgrass by ammonia fiber explosion (AFEX) 总被引:3,自引:0,他引:3
Hasan Alizadeh Farzaneh Teymouri Thomas I. Gilbert Bruce E. Dale 《Applied biochemistry and biotechnology》2005,124(1-3):1133-1141
The effects of ammonia fiber explosion (AFEX) pretreatment of switch grass using its major process variables are reported.
The optimal pretreatment conditions for switchgrass were found to be near 100°C reactor temperature, and ammonia loading of
1:1 kg of ammonia: kg of dry matter with 80% moisture content (dry weight basis [dwb]) at 5 min residence time. Hydrolysis
results of AFEX-treated and untreated samples showed 93% vs 16% glucan conversion, respectively. The ethanol yield of optimized
AFEX-treated switchgrass was measured to be about 0.2 g ethanol/g dry biomass, which is 2.5 times more than that of the untreated
sample. 相似文献
4.
Enzymatic saccharification and fermentation of xylose-optimized dilute acid-treated lignocellulosics
Yun-Chin Chung Alan Bakalinsky Michael H. Penner 《Applied biochemistry and biotechnology》2005,124(1-3):947-961
The cellulose reactivity of two lignocellulosic feedstocks, switchgrass and poplar, was evaluated under straight saccharification
(SS) and simultaneous saccharification and fermentation (SSF) conditions following dilute sulfuric acid pretreatments designed
for optimum xylose yields. The optimum pretreatment conditions, within the constraints of the experimental system (Parr batch
reactor), were 1.2% acid, 180°C, and 0.5 min for switchgrass and 1% acid, 180°C, and 0.56 min for poplar. The cellulase enzyme
preparation was from Trichoderma reesei and fermentations were done with Saccharomyces cerevisiae. Time courses for SS were monitored as the sum of glucose and cellobiose; those for SSF as the sum of glucose, cellobiose,
and ethanol. Percentage conversions under SS conditions were 79.1% and 91.4% for the pretreated poplar and switchgrass feedstocks,
respectively. Analogous values under SSF conditions were 73.0% and 90.3% for pretreated poplar and switchgrass, respectively. 相似文献
5.
Hasmet Emre Akman Nuriye Altnay Perendeci Can Ertekin Osman Yaldiz 《Molecules (Basel, Switzerland)》2022,27(20)
Switchgrass earned its place globally as a significant energy crop by possessing essential properties such as being able to control erosion, low cost of production, biomass richness, and appeal for biofuel production. In this study, the impact of a Ca(OH)2-assisted thermal pretreatment process on the switchgrass variety Shawnee for methane fuel production was investigated. The Ca(OH)2-assisted thermal pretreatment process was optimized to enhance the methane production potential of switchgrass. Solid loading (3–7%), Ca(OH)2 concentration (0–2%), reaction temperature (50–100 °C), and reaction time (6–16 h) were selected as independent variables for the optimization. Methane production was obtained as 248.7 mL CH4 gVS−1 under the optimized pretreatment conditions. Specifically, a reaction temperature of 100 °C, a reaction time of 6 h, 0% Ca(OH)2, and 3% solid loading. Compared to raw switchgrass, methane production was enhanced by 14.5%. Additionally, the changes in surface properties and bond structure, along with the kinetic parameters from first order, cone, reaction curve, and modified Gompertz modeling revealed the importance of optimization. 相似文献
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