共查询到20条相似文献,搜索用时 9 毫秒
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The measurement of gas concentrations in fermenters is vital for monitoring and controlling a great variety of biotechnological processes. At present, most systems analyse the content of inflowing and outflowing gas streams. The information obtained in this way has proved to be very useful, but gas phase analyses suffer from a considerable disadvantage; the gas composition of the outflow does not precisely reflect the gas composition of the microbes' environment at the time the measurements are made. To overcome this problem, new systems have been developed which measure the concentration of gases (particularly O2, CO2 and H2) dissolved in fermentation liquids. 相似文献
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H. W. Doelle 《Antonie van Leeuwenhoek》1966,32(1):373-380
A simplified extraction method of high efficiency has been worked out to permit the determination of small amounts of alcohols present in fermentation solutions. Methods of extracting are described for large and small amounts of culture media. The proposed method has been successfully applied to known amounts of alcohol in bacterial fermentation solutions. Clostridium acetobutylicum andZymomonas mobilis were used for this investigation. The method is described in details with theClostridium culture. 相似文献
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An extraction method coupled with gas-chromatographic analysis has been devised for the determination of small amounts of C1-C7 branched and straight-chain saturated fatty acids as well as 18 mono-, di- and tricarboxylic acids and related compounds, the latter being analyzed either as their methylesters or as their trimethylsilyl-derivatives. Methods for extracting non-volatile acids or both volatile and non-volatile acids are described for large and small volumes of culture media. The proposed methods have been successfully applied to the determination of non-acidic fermentation products, known amounts of alcohols, and to volatile and non-volatile acids in bacterial fermentation solutions, namely a batch culture ofLactobacillus casei subsp.rhamnosus ATCC 7469. A carbon balance sheet of this organism's metabolic behaviour throughout growth is proposed. 相似文献
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Michael Schopferer Harald Bär Bernhard Hochstein Norbert Mücke Norbert Willenbacher 《Journal of molecular biology》2009,388(1):133-1006
We have investigated the viscoelastic properties of the cytoplasmic intermediate filament (IF) proteins desmin and vimentin. Mechanical measurements were supported by time-dependent electron microscopy studies of the assembly process under similar conditions. Network formation starts within 2 min, but it takes more than 30 min until equilibrium mechanical network strength is reached. Filament bundling is more pronounced for desmin than for vimentin. Desmin filaments (persistence length lp ≈ 900 nm) are stiffer than vimentin filaments (lp ≈ 400 nm), but both IFs are much more flexible than microfilaments. The concentration dependence of the plateau modulus G0 ∼ cα is much weaker than predicted theoretically for networks of semiflexible filaments. This is more pronounced for vimentin (α = 0.47) than for desmin (α = 0.70). Both networks exhibit strain stiffening at large shear deformations. At the transition from linear to nonlinear viscoelastic response, only desmin shows characteristics of nonaffine network deformation. Strain stiffening and the maximum modulus occur at strain amplitudes about an order of magnitude larger than those for microfilaments. This is probably attributable to axial slippage within the tetramer building blocks of the IFs. Network deformation beyond a critical strain γmax results in irreversible damage. Strain stiffening sets in at lower concentrations, is more pronounced, and is less sensitive to ionic strength for desmin than for vimentin. Hence, desmin exhibits strain stiffening even at low-salt concentrations, which is not observed for vimentin, and we conclude that the strength of electrostatic repulsion compared to the strength of attractive interactions forming the network junctions is significantly weaker for desmin than for vimentin filaments. These findings indicate that both IFs exhibit distinct mechanical properties that are adapted to their respective cellular surroundings [i.e., myocytes (desmin) and fibroblasts (vimentin)]. 相似文献
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Properties of perfluorinated liquids 总被引:6,自引:0,他引:6
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Summary A new sauerkraut fermentation vat with external recycling of brine is described. This system allows the control of fermentation, improves the homogeneity of final product and accelerates theacidification by the usual lactic-acid bacteria. 相似文献
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Oxygen transfer in liquids 总被引:1,自引:0,他引:1
In the laboratory-type airlift tower reactor oxygen transfer from air in tap water and/or polyacrylamide solutions (Neuperm WF) was studied. In order to characterize the system, volumetric coefficient of oxygen transfer was determined by the gassing-out method. Two arrangements of the airlift tower reactor were compared, namely the reactor with and without motionless mixer. In addition, mean relative gas holdup and gas power output were determined for both arrangements. 相似文献
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Kocho fermentation 总被引:1,自引:0,他引:1
B. A. Gashe 《Journal of applied microbiology》1987,62(6):473-477
Kocho, an acidic starchy food, is prepared by fermenting a mixture of the scraping of the trunk and pulverized stem and corm of ensette ( Ensette ventricosum). Leuconostoc mesenteroides is responsible for initiating the fermentation. Because of the activities of this species and, to some extent, of Streptococcus faecalis , the pH of the fermenting kocho was reduced from 6˙5 to 5˙6. These organisms were then succeeded by the homofermentative bacteria Lactobacillus coryneformis subsp. coryne-formis and Lact. plantarum . Through the activities of the Lactobacillus species, the pH was further reduced to 4˙2. Pediococcus cerevisiae , although present in kocho, did not achieve prominence because of the relatively low fermentation temperature (14°-18°C). Spore-formers were present in fairly high numbers during the first 15 d of fermentation. It was suspected that the butyrous odour which was detected during the first 2 weeks in fermenting kocho might be due to the activities of certain clostridial species. Yeasts were also present in fairly high numbers. 相似文献
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《Biochemical Engineering Journal》2003,13(2-3):81-84
Solid-state fermentation has emerged as a potential technology for the production of microbial products such as feed, fuel, food, industrial chemicals and pharmaceutical products. Its application in bioprocesses such as bioleaching, biobeneficiation, bioremediation, biopulping, etc. has offered several advantages. Utilisation of agro-industrial residues as substrates in SSF processes provides an alternative avenue and value-addition to these otherwise under- or non-utilised residues. Today with better understanding of biochemical engineering aspects, particularly on mathematical modelling and design of bioreactors (fermenters), it is possible to scale up SSF processes and some designs have been developed for commercialisation. It is hoped that with continuity in current trends, SSF technology would be well developed at par with submerged fermentation technology in times to come. 相似文献
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Miso is a fermented food widely consumed in the Orient and is prepared from mold rice, soybeans and salt. About 13 million bushels of soybeans are made into miso each year, the annualproduction amounting to 974,000 metric tons. 相似文献
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Dai Jian-Ying Ma Lin-Hui Wang Zhuang-Fei Guan Wen-Tian Xiu Zhi-Long 《Bioprocess and biosystems engineering》2017,40(3):423-429
Bioprocess and Biosystems Engineering - Acetoin is a natural flavor and an important bio-based chemical which could be separated from fermentation broth by solvent extraction, salting-out... 相似文献