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1.
Ethanol fermentations were conducted using both whole corn, and corn with 100% of the germ, and a portion (∼74%) of the fiber
removed. Ethanol production increased 11% in the germ and fiber-removed corn vs the whole corn. The protein content of distiller's
dried grains and solubles increased from 30 to 36%, and phosphate levels were 60% lower in corn with germ and fiber removed
vs whole corn. Removal of germ and fiber prior to fermentation allows higher starch loading and results in increased ethanol
production. The integration of germ and fiber removal in the dry-grind ethanol industry could increase capacity and add valuable
coproducts, resulting in increased productivity and profits. 相似文献
2.
A novel type of acetylated cellulose nanofibre (CNF) was extracted successfully from sisal fibres using chemical methods. Initially, a strong alkali treatment was used to swell the fibres, followed by a bleaching step to remove the residual lignin and finally an acetylation step to reduce the impact of the intermolecular hydrogen bonds in the nanocellulose. The result of this sequence of up-scalable chemical treatments was a pulp consisting mainly of micro-sized fibres, which allowed simpler handling through filtration and purification steps and permitted the isolation of an intermediate product with a high solids content. An aqueous dispersion of CNF could be obtained directly from this intermediate pulp by simple magnetic stirring. As a proof of concept, the dispersion was used directly for preparing a highly translucent CNF film, illustrating that there are no large aggregates in the prepared CNF dispersion. Finally, CNF films with alkali extracts were also prepared, resulting in flatter films with an increased mass yield and improved mechanical strength. 相似文献
3.
Corn fiber, which consists of about 20% starch, 14% cellulose, and 35% hemicellulose, has the potential to serve as a low
cost feedstock for production of fuel ethanol. Currently, the use of corn fiber to produce fuel ethanol faces significant
technical and economic challenges. Its success depends largely on the development of environmentally friendly pretreatment
procedures, highly effective enzyme systems for conversion of pretreated corn fiber to fermentable sugars, and efficient microorganisms
to convert multiple sugars to ethanol. Several promising pretreatment and enzymatic processes for conversion of corn fiber
cellulose, hemicellulose, and remaining starch to fermentable sugars were evaluated. These hydrolyzates were then examined
for ethanol production in bioreactors, using genetically modified bacteria and yeast. Several novel enzymes were also developed
for use in pretreated corn fiber saccharification.
Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard
of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also
be suitable. 相似文献
4.
Carbon dioxide reforming of ethanol over Rh/CeO 2 catalyst was deeply investigated at different reaction temperatures of 450–700 °C and reactant ratios (CO 2/ethanol from 1 to 3) under atmospheric pressure. The obtained results indicated that Rh/CeO 2 catalyst presented a promising activity and stability for syngas production from renewable bio-ethanol instead of conventional methane. Typically, CO 2-rich conditions (CO 2/ethanol = 3) were favorable for reaction process and dynamic coke cleaning, which led to remarkably stable performance over 65 h on stream. The strong redox capacity of CeO 2 support might also accelerate CO 2 activation and prevent the carbon accumulation over the catalyst surface. Additionally, tunable H 2/CO ratios were available by changing the CO 2/ethanol ratios. The results from characterization of samples before and after catalytic tests allowed to establish the relationship between textural properties and catalytic performance. 相似文献
5.
Applied Biochemistry and Biotechnology - The present work examines the production of ethanol via direct fermentation of pure celluloses and lignocellulosic wastes by two soil fungi isolated under... 相似文献
6.
The reduction of CO_2 emission is crucial for the mitigation of climate change.A considerable amount of industrial CO_2 can be absorbed in the form of carbonates through high-temperature sorption processes.In this regard,the efficient conversion of carbonates to value-added products will provide an economically viable method for the sustainable usage of carbon compounds.Herein,we report a promising solution involving the use of a glycerol and ethanol mixture as a hydrogen donor in the dry reforming process with CaCO_3 to produce syngas.A series of metal active components,including Ni,Fe,Co,Cu,Pt,Pd,Ru,and Rh,was used to promote this reaction.Ni showed comparable performance with that of Pd,but outperformed Co,Fe,Cu,Rh,Ru,and Pt.Approximately 100%conversion of glycerol and ethanol,~92%selectivity of synthesis gas (H_2 and CO),and a H_2/CO ratio of~1.2 were achieved over CaCO_3 containing10 wt%Ni (10Ni-CaCO_3).Meanwhile,the CO_2 concentration was less than 5 vol%,indicating that most of the CO_2 captured by the carbonate can be transformed into chemicals;however,they cannot simply be emitted.The CO_2 released from the decomposition of CaCO_3 not only adjusted the ratio of H_2 to CO but also eliminated cokes to guarantee the CO_2 absorption-conversion cyclic stability in the absence of steam and at high temperatures. 相似文献
7.
Corn cobs obtained as waste from the corn industry, were analyzed by a TG-DTA unit in an atmosphere of flowing nitrogen. The carbonaceous products so formed were then produced on a preparative scale and activated chemically using potassium hydroxide. This resulted in the formation of a carbon with a very high surface area. The active carbon produced was then examined using thermal analysis in the temperature jump mode on a thermogravimetry unit. From this data the kinetics of degradation of the active carbon was determined using zero order rate kinetics. The pore structure of the active material was also examined using SEM. The E
a for activated corn cobs was found to be 106 kJ mol –1. 相似文献
8.
Although glycosyl inositol phosphoryl ceramides (GIPCs) represent the most abundant class of sphingolipids in plants, they still remain poorly characterized in terms of structure and biodiversity. More than 50 years after their discovery, little is known about their subcellular distribution and their exact roles in membrane structure and biological functions. This review is focused on extraction and characterization methods of GIPCs occurring in plants and fungi. Global methods for characterizing ceramide moieties of GIPCs revealed the structures of long-chain bases (LCBs) and fatty acids (FAs): LCBs are dominated by tri-hydroxylated molecules such as monounsaturated and saturated phytosphingosine (t18:1 and t18:0, respectively) in plants and mainly phytosphingosine (t18:0 and t20:0) in fungi; FA are generally 14–26 carbon atoms long in plants and 16–26 carbon atoms long in fungi, these chains being often hydroxylated in position 2. Mass spectrometry plays a pivotal role in the assessment of GIPC diversity and the characterization of their structures. Indeed, it allowed to determine that the core structure of GIPC polar heads in plants is Hex(R1)-HexA-IPC, with R1 being a hydroxyl, an amine, or a N-acetylamine group, whereas the core structure in fungi is Man-IPC. Notably, information gained from tandem mass spectrometry spectra was most useful to describe the huge variety of structures encountered in plants and fungi and reveal GIPCs with yet uncharacterized polar head structures, such as hexose–inositol phosphoceramide in Chondracanthus acicularis and (hexuronic acid) 4–inositol phosphoceramide and hexose–(hexuronic acid) 3–inositol phosphoceramide in Ulva lactuca. Figure Example of GIPC with its three building blocks (fatty acid, FA; long chain base, LCB; polar head) where R1 could be a hydroxyl, an amine or a N-acetylamine group 相似文献
9.
Dilute acid hydrolysate of corn fiber was used as carbon source for the production of succinic acid by Actinobacillus succinogenes NJ113. The optimized hydrolysis conditions were obtained by orthogonal experiments. When corn fiber particles were of 20
mesh in size and treated with 1.0% sulfuric acid at 121 °C for 2 h, the total sugar yield could reach 63.3%. It was found
that CaCO 3 neutralization combined with activated carbon adsorption was an effective method to remove fermentation inhibitors especially
furfural that presented in the acid hydrolysate of corn fiber. Only 5.2% of the total sugar was lost, while 91.9% of furfural
was removed. The yield of succinic acid was higher than 72.0% with the detoxified corn fiber hydrolysate as the carbon source
in anaerobic bottles or 7.5 L fermentor cultures. It was proved that the corn fiber hydrolysate could be an alternative to
glucose for the production of succinic acid by A. succinogenes NJ113. 相似文献
10.
Kinetics of ethanol production from carob pods extract by immobilized S. cerevisiae cells in static and shake flask fermentation have been investigated. Shake flask fermentation proved to be a better fermentation system for the production of ethanol than static fermentation. The optimum values of ethanol concentration, ethanol productivity, ethanol yield, and fermentation efficiency were obtained at pH range 3.5–6.5 and temperature between 30–35°C. A maximum ethanol concentration (65 g/L), ethanol productivity (8.3 g/Lh), ethanol yield (0.44 g/g), and fermentation efficiency (95%) was achieved at an initial sugar concentration of 200, 150, 100, and 200 g/L, respectively. The highest values of specific ethanol production rate and specific sugar uptake rate were obtained at pH 6.5, temperature 40°C, and initial sugar concentration of 100 g/L. Other kinetic parameters, biomass concentration, biomass yield, and specific biomass production rate were maximum at pH 5.5, temperature 30°C, and initial sugar concentration 150 g/L. Under the same fermentation conditions non-sterilized carob pod extract gave higher ethanol concentration than sterilized medium. In repeated batch fermentations, the immobilized S. cerevisiae cells in Ca-alginate beads retained their ability to produce ethanol for 5 d. 相似文献
11.
In the present work, Pb(II) and Cd(II) ion adsorption onto inert organic matter (IOM) obtained from ground dried plants: Euphorbia echinus, Launea arborescens, Senecio anthophorbium growing in semi-arid zones of Morocco and Carpobrotus edulis as the Mediterranean plant has been studied. A suspension of plant deroed micro-particles adsorbs lead and cadmium present as ionic species, with a higher affinity for Pb(II). The kinetics and the maximum capacity adsorption depend on the type of plant as well as on the metal ions (atomic weight, ionic radius and electronegativity). The adsorption process is affected by various parameters such as contact time, solution volume to mass of plant particles ratio (m/V), particle size, solution pH and metal concentration. A dose of 25 g/l of adsorbent was optimal to obtain maximum adsorption of both metal ions. The maximum metal uptake was obtained with particles of organic matter of <50 microm. As to classical ionic adsorption phenomena, the adsorption of both metal ions increases with the increase of the initial concentration in the solution. For the two metal cations, the uptake efficiency of the studied plants ranged from: C. edulis>E. echinus>S. anthophorbium>L. arborescens, however, the differences are rather small. Two different waste water types (domestic and industrial) were tested and good results were obtained for removal of Pb(II) and Cd(II) at more than 90%. The removal of the metal and mineral ions waste water was observed for PO(4)(3-) at 88%, for NO(3)(-) at 96.5% and for metal ions (Pb(II), Cd(II), Cu(II) and Zn(II)) at about 100%, using IOM as absorbent. 相似文献
12.
The catalytic role of various inert solid supports on acceleration of alcohol fermentation by Saccharomyces cerevisiae was investigated. The enhanced rate of alcohol production was dependent on the nature of the support as well as on the amount
used. Among all the tested supports, chitosan flakes showed the maximum yield of alcohol (93% of theoretical yield). This
higher rate of alcohol production was associated with the twofold increase in the activity of alcohol dehydrogenase over control.
Our results suggest that the addition of a small fraction of solids in submerged fermentations to facilitate cell anchorage
for enhanced metabolic activity is easier and more economical compared to cell immobilization processes.
IICT Communication No. 4266. Some of the results in this article are covered under a patent. 相似文献
13.
Corn fiber is the fibrous by-product of wet-mill corn processing. It typically consists of about 20% starch, 14% cellulose,
and 30% hemicellulose in the form of arabinoxylan. Crude corn fiber (CCF) was fractionated into de-starched corn fiber (DSCF),
corn fiber with cellulose (CFC) enriched, and corn fiber arabinoxylan (CFAX), and these fractions were evaluated as substrates
for enzyme production by Trichoderma reesei. T. reesei QM9414 and Rut C-30 grew on CCF, DSCF, CFC, or CFAX and secreted a number of hydrolytic enzymes. The enzymes displayed synergism
with commercial cellulases for corn fiber hydrolysis.
Mention of trade names or commercial products in this article is solely for the purpose of providing specific information
and does not imply recommendation or endorsement by the U.S. Department of Agriculture. 相似文献
14.
Applied Biochemistry and Biotechnology - Escherichia coli strain B, bearing thepet plasmid pLOI297, and the wild-type culture, lacking the plasmid, responded to aeration of the complex medium by an... 相似文献
15.
In ethanol production from lignocellulose by enzymatic hydrolysis and fermentation, it is desirable to minimize addition of
fresh-water and waste-water streams, which leads to an accumulation of substances in the process. This study shows that the
amount of fresh water used and the amount of waste water thereby produced in the production of fuel ethanol from softwood,
can be reduced to a large extent by recycling of either the stillage stream or part of the liquid stream from the fermenter.
A reduction in fresh-water demand of more than 50%, from 3 kg/kg dry raw material to 1.5 kg/kg dry raw material was obtained
without any negative effects on either hydrolysis or fermentation. A further decrease in the amount of fresh water, to one-fourth
of what was used without recycling of process streams, resulted in a considerable decrease in the ethanol productivity and
a slight decrease in the ethanol yield 相似文献
16.
The continuous production of ethanol from nonsterilized carob pod extract by immobilized Saccharomyces cerevisiae on mineral kissiris using one- and two-reactor systems has been investigated. A maximum ethanol productivity of 9.6 g/L/h
was obtained at an initial sugar concentration of 200 g/L and D = 0.4 h -1 with 68% of theoretical yield and 34% of sugar utilization using the one-reactor system. At S
0 = 200 g/L, D = 0.05 h -1, 83% of theoretical yield, and 64% of sugar utilization, an ethanol productivity of 2.6 g/L/h was achieved. In the tworeactor
system, a maximum ethanol productivity of 11.4 g/L/h was obtained at S 0 = 200 g/L and D = 0.4 h -1 with 68.5% of theoretical yield and 41.5% of sugar utilization. The two-reactor system was operated at a constant dilution
rate of 0.3 h -1 for 60 d without loss of the original immobilized yeast activity. In this case, the average ethanol productivity, ethanol
yield (% of theoretical), and sugar utilization were 10.7 g/L/h, 71.5%, and 48%, respectively. 相似文献
17.
Applied Biochemistry and Biotechnology - In this study, fermentation tests on different initial glucose concentrations, ranging from 100 to 200 g/L, were conducted to identify the ethanol tolerance... 相似文献
18.
The ethanologenic bacteria Escherichia coli strains KO11 and LYO1, and Klebsiella oxytoca strain P2, were investigated for their ability to metabolize furfural. Using high performance liquid chromatography and 13C-nuclear magnetic resonance spectroscopy, furfural was found to be completely biotransformed into furfuryl alcohol by each
of the three strains with tryptone and yeast extract as sole carbon sources. This reduction appears to be constitutive with
NAD(P)H acting as electron donor. Glucose was shown to be an effective source of reducing power. Succinate inhibited furfural
reduction, indicating that flavins are unlikely participants in this process. Furfural at concentrations >10 m M decreased the rate of ethanol formation but did not affect the final yield. Insight into the biochemical nature of this furfural
reduction process may help efforts to mitigate furfural toxicity during ethanol production by ethanologenic bacteria. 相似文献
19.
Direct production of ethyl levulinate (EL) from glucose catalysed by a liquid acid catalyst (sulfuric acid) and a solid acid zeolite catalyst USY NKF-7 (USY) in ethanol media was investigated in this study. Effects of the initial glucose concentration ( C G0), reaction temperature ( T), amount of acid catalyst, and water addition on the yields of EL were compared, respectively. The results show that higher yield of EL can be obtained at lower C G0. Higher temperature and acid concentration can accelerate the reaction rate, but the formation rate of the by-products increases more quickly than that of EL. Water addition also can result in the decrease of the yield of EL. Although sulfuric acid is efficient in the production of EL, the USY is more efficient in converting glucose to 5-ethoxymethyl-2-furaldehyde. Moreover, the use of USY can limit the diethyl ether production, and it can be reused for multiple times. 相似文献
20.
This article describes a systematic study of the nutritional requirements of a patented recombinant ethanologenicEscherichia coli (11303:pLOI297) and provides cost-effective formulations that are compatible with the production of fuel ethanol in fermentations of lignocellulosic prehydrolysate characterized by high xylose conversion efficiency. A complex and nutrient-rich laboratory medium, Luria broth (LB), provided the benchmark with respect to fermentation performance standard. Xylose fermentation performance was assessed in terms of the target values for operational process parameters established by the US National Renewable Energy Laboratory (NREL)—final ethanol concentration (25 g/L), xylose-to-ethanol conversion efficiency (90%), and volumetric productivity (0.52 g/L·h). Biomass prehydrolysates that are rich in xylose also contain acetic acid, and in anticipation of a need to reduce acetic acid toxicity, the fermentors were operated with a pH control set-point of 7.0 Growth and fermentation in the minimal defined salts (DS) medium was only about 15% compared to the reference medium. Amendment of the minimal medium containing 6 wt% xylose with both vitamins and amino acids resulted in improved growth, but the volume productivity (0.59 g/L·h) was still only about 54% of that with LB (1.1 g/L·h). Formulations directed at cost reduction through the use of less expensive commercial complex nutritional supplements were within 90% of the NREL process target with respect to yield and provided a productivity at about 80% of the LB medium, but were not economical. Corn steep liquor (CSL) at about 7–8 g/L was shown to be a complete source of nutritional requirements and supported a fermentation performance approaching that of LB. At a cost of CSL of $50/t (dry wt), the economic impact of using this amount CSL as the sole nutritional supplement in a cellulosic ethanol plant was estimated to be about 4¢/gal of ethanol. 相似文献
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