共查询到20条相似文献,搜索用时 46 毫秒
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Li YZ Pan YH Sun CB Dong HT Luo XL Wang ZQ Tang JL Chen B 《Plant molecular biology》2010,74(6):573-590
A cDNA library was constructed from the root tissues of cassava variety Huanan 124 at the root bulking stage. A total of 9,600
cDNA clones from the library were sequenced with single-pass from the 5′-terminus to establish a catalogue of expressed sequence
tags (ESTs). Assembly of the resulting EST sequences resulted in 2,878 putative unigenes. Blastn analysis showed that 62.6%
of the unigenes matched with known cassava ESTs and the rest had no ‘hits’ against the cassava database in the integrative
PlantGDB database. Blastx analysis showed that 1,715 (59.59%) of the unigenes matched with one or more GenBank protein entries
and 1,163 (40.41%) had no ‘hits’. A cDNA microarray with 2,878 unigenes was developed and used to analyze gene expression
profiling of Huanan 124 at key growth stages including seedling, formation of root system, root bulking, and starch maturity.
Array data analysis revealed that (1) the higher ratio of up-regulated ribosome-related genes was accompanied by a high ratio
of up-regulated ubiquitin, proteasome-related and protease genes in cassava roots; (2) starch formation and degradation simultaneously
occur at the early stages of root development but starch degradation is declined partially due to decrease in UDP-glucose
dehydrogenase activity with root maturity; (3) starch may also be synthesized in situ in roots; (4) starch synthesis, translocation,
and accumulation are also associated probably with signaling pathways that parallel Wnt, LAM, TCS and ErbB signaling pathways
in animals; (5) constitutive expression of stress-responsive genes may be due to the adaptation of cassava to harsh environments
during long-term evolution. 相似文献
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Nitayavardhana S Rakshit SK Grewell D van Leeuwen JH Khanal SK 《Biotechnology and bioengineering》2008,101(3):487-496
The use of ultrasound pretreatment to enhance liquefaction and saccharification of cassava chips was investigated. Cassava chip slurry samples were subjected to sonication for 10-40 s at three power levels of low (2 W/mL), medium (5 W/mL), and high (8 W/mL). The samples were simultaneously exposed to enzymes to convert starch into glucose. The cassava particle size declined nearly 40-fold following ultrasonic pretreatment at high power input. Scanning electron micrographs of both unsonicated (control) and sonicated samples showed disruption of fibrous material in cassava chips but did not affect the granular structure of starch. Reducing sugar release improved in direct proportion to the power input and sonication time. The reducing sugar increase was as much as 180% with respect to the control groups. The slurry samples with enzyme addition during sonication resulted in better reducing sugar release than the samples with enzyme addition after sonication. The heat generated during sonication below starch gelatinization temperature apparently had no effect on the reducing sugar release. The reducing sugar yield and energy efficiency of ultrasound pretreated samples increased with total solids (TS) contents. The highest reducing sugar yield of 22 g/100 g of sample and efficiency of 323% were obtained for cassava slurry with 25% TS at high power. The reducing sugar yield at the completion of reaction (R(infinity)) were over twofold higher compared to the control groups. The integration of ultrasound into a cassava-based ethanol plant may significantly improve the overall ethanol yield. 相似文献
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In the root of horse radish, sucrose, fructose, glucose and two unknown fructose-oligosac-charides were found in the form of free sugars, in the decreasing order just given, and large amounts of starch, hot 50% methanol-soluble polysaccharide, water-soluble polysaccharide, pectin, hemicellulose, cellulose and a small amount of lignin were found as polysaccharides. As the constructive sugar of these polysaccharides, the following, i.e., glucose, fructose, galactose, arabinose, galacturonic acid and xylose were detected. 相似文献
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Field testing and exploitation of genetically modified cassava with low-amylose or amylose-free starch in Indonesia 总被引:1,自引:0,他引:1
Koehorst-van Putten HJ Sudarmonowati E Herman M Pereira-Bertram IJ Wolters AM Meima H de Vetten N Raemakers CJ Visser RG 《Transgenic research》2012,21(1):39-50
The development and testing in the field of genetically modified -so called- orphan crops like cassava in tropical countries
is still in its infancy, despite the fact that cassava is not only used for food and feed but is also an important industrial
crop. As traditional breeding of cassava is difficult (allodiploid, vegetatively propagated, outbreeding species) it is an
ideal crop for improvement through genetic modification. We here report on the results of production and field testing of
genetically modified low-amylose transformants of commercial cassava variety Adira4 in Indonesia. Twenty four transformants
were produced and selected in the Netherlands based on phenotypic and molecular analyses. Nodal cuttings of these plants were
sent to Indonesia where they were grown under biosafety conditions. After two screenhouse tests 15 transformants remained
for a field trial. The tuberous root yield of 10 transformants was not significantly different from the control. Starch from
transformants in which amylose was very low or absent showed all physical and rheological properties as expected from amylose-free
cassava starch. The improved functionality of the starch was shown for an adipate acetate starch which was made into a tomato
sauce. This is the first account of a field trial with transgenic cassava which shows that by using genetic modification it
is possible to obtain low-amylose cassava plants with commercial potential with good root yield and starch quality. 相似文献
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Sugimoto T Makita T Watanabe K Shoji H 《Journal of industrial microbiology & biotechnology》2012,39(4):605-612
Cassava is a starch-containing root crop that is widely used as a raw material in a variety of industrial applications, most
recently in the production of fuel ethanol. In the present study, ethanol production from raw (uncooked) cassava flour by
simultaneous saccharification and fermentation (SSF) using a preparation consisting of multiple enzyme activities from Aspergillus kawachii FS005 was investigated. The multi-activity preparation was obtained from a novel submerged fermentation broth of A. kawachii FS005 grown on unmilled crude barley as a carbon source. The preparation was found to consist of glucoamylase, acid-stable
α-amylase, acid carboxypeptidase, acid protease, cellulase and xylanase activities, and exhibited glucose and free amino nitrogen
(FAN) production rates of 37.7 and 118.7 mg/l/h, respectively, during A. kawachii FS005-mediated saccharification of uncooked raw cassava flour. Ethanol production from 18.2% (w/v) dry uncooked solids of
raw cassava flour by SSF with the multi-activity enzyme preparation yielded 9.0% (v/v) of ethanol and 92.3% fermentation efficiency.
A feasibility study for ethanol production by SSF with a two-step mash using raw cassava flour and the multi-activity enzyme
preparation manufactured on-site was verified on a pilot plant scale. The enzyme preparation obtained from the A. kawachii FS005 culture broth exhibited glucose and FAN production rates of 41.1 and 135.5 mg/l/h, respectively. SSF performed in a
mash volume of about 1,612 l containing 20.6% (w/v) dry raw cassava solids and 106 l of on-site manufactured A. kawachii FS005 culture broth yielded 10.3% (v/v) ethanol and a fermentation efficiency of 92.7%. 相似文献
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Summary The conventional saccharification of cassava root by enzymatic hydrolysis is improved by using a little amount of cellulase and cellobiase in addition to conventional enzyme, glucoamylase. With new saccharification[glucoamylase 0.45SGU/g cassava, cellulase 4.5NCU/g cassava, cellobiase 0.09U/g cassava, pH 4.3, temperature 60°C, total volume 465ml : 100g of cassava/400ml of water], the reaction time was reduced by about 5 hours, the concentration of reducing sugar was increased by 40%, glucose production was enhanced by 10% , and the viscosity was reduced by 30%. 相似文献
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Characterization of a novel amylolytic enzyme encoded by a gene from a soil-derived metagenomic library 总被引:16,自引:0,他引:16
Yun J Kang S Park S Yoon H Kim MJ Heu S Ryu S 《Applied and environmental microbiology》2004,70(12):7229-7235
It has been estimated that less than 1% of the microorganisms in nature can be cultivated by conventional techniques. Thus, the classical approach of isolating enzymes from pure cultures allows the analysis of only a subset of the total naturally occurring microbiota in environmental samples enriched in microorganisms. To isolate useful microbial enzymes from uncultured soil microorganisms, a metagenome was isolated from soil samples, and a metagenomic library was constructed by using the pUC19 vector. The library was screened for amylase activity, and one clone from among approximately 30,000 recombinant Escherichia coli clones showed amylase activity. Sequencing of the clone revealed a novel amylolytic enzyme expressed from a novel gene. The putative amylase gene (amyM) was overexpressed and purified for characterization. Optimal conditions for the enzyme activity of the AmyM protein were 42 degrees C and pH 9.0; Ca2+ stabilized the activity. The amylase hydrolyzed soluble starch and cyclodextrins to produce high levels of maltose and hydrolyzed pullulan to panose. The enzyme showed a high transglycosylation activity, making alpha-(1, 4) linkages exclusively. The hydrolysis and transglycosylation properties of AmyM suggest that it has novel characteristics and can be regarded as an intermediate type of maltogenic amylase, alpha-amylase, and 4-alpha-glucanotransferase. 相似文献
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Direct fermentation of raw starch using a Kluyveromyces marxianus strain that expresses glucoamylase and Alpha‐amylase to produce ethanol
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Raw starch and raw cassava tuber powder were directly and efficiently fermented at elevated temperatures to produce ethanol using the thermotolerant yeast Kluyveromyces marxianus that expresses α‐amylase from Aspergillus oryzae as well as α‐amylase and glucoamylase from Debaryomyces occidentalis. Among the constructed K. marxianus strains, YRL 009 had the highest efficiency in direct starch fermentation. Raw starch from corn, potato, cassava, or wheat can be fermented at temperatures higher than 40°C. At the optimal fermentation temperature 42°C, YRL 009 produced 66.52 g/L ethanol from 200 g/L cassava starch, which was the highest production among the selected raw starches. This production increased to 79.75 g/L ethanol with a 78.3% theoretical yield (with all cassava starch were consumed) from raw cassava starch at higher initial cell densities. Fermentation was also carried out at 45 and 48°C. By using 200 g/L raw cassava starch, 137.11 and 87.71 g/L sugar were consumed with 55.36 and 32.16 g/L ethanol produced, respectively. Furthermore, this strain could directly ferment 200 g/L nonsterile raw cassava tuber powder (containing 178.52 g/L cassava starch) without additional nutritional supplements to produce 69.73 g/L ethanol by consuming 166.07 g/L sugar at 42°C. YRL 009, which has consolidated bioprocessing ability, is the best strain for fermenting starches at elevated temperatures that has been reported to date. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:338–347, 2014 相似文献
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Lopez C Jorge V Piégu B Mba C Cortes D Restrepo S Soto M Laudié M Berger C Cooke R Delseny M Tohme J Verdier V 《Plant molecular biology》2004,56(4):541-554
Two economically important characters, starch content and cassava bacterial blight resistance, were targeted to generate a large collection of cassava ESTs. Two libraries were constructed from cassava root tissues of varieties with high and low starch contents. Other libraries were constructed from plant tissues challenged by the pathogen Xanthomonas axonopodis pv.manihotis. We report here the single pass sequencing of 11 954 cDNA clones from the 5’ ends, including 111 from the 3’ ends. Cluster analysis permitted the identification of a unigene set of 5700 sequences. Sequence analyses permitted the assignment of a putative functional category for 37% of sequences whereas ~ 16% sequences did not show any significant similarity with other proteins present in the database and therefore can be considered as cassava specific genes. A group of genes belonging to a large multigene family was identified. We characterize a set of genes detected only in infected libraries putatively involved in the defense response to pathogen infection. By comparing two libraries obtained from cultivars contrasting in their starch content a group of genes associated to starch biosynthesis and differentially expressed was identified. This is the first large cassava EST resource developed today and publicly available thus making a significant contribution to genomic knowledge of cassava. 相似文献