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Journal of biochemical toxicology最新文献

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Effect of cooperativity on microbial growth 协同性对微生物生长的影响
Journal of biochemical toxicology Pub Date : 2007-05-29 DOI: 10.1002/JBT.2570270612
F. Kargı
{"title":"Effect of cooperativity on microbial growth","authors":"F. Kargı","doi":"10.1002/JBT.2570270612","DOIUrl":"https://doi.org/10.1002/JBT.2570270612","url":null,"abstract":"The classical Monod equation for the specific growth rate of a microbial population can be derived by assuming a single substrate enzyme-catalysed reaction (Michaelis-Menten kinetics) as the rate-limiting step in microbial growth. In some cases the enzyme which catalyses the rate-limiting step in microbial growth may have more than one substrate binding site and the binding of one substrate molecule to the enzyme facilitates the binding of the next substrate molecule (cooperativity). The presence of cooperativity changes the form of the Michaelis-Menten equation for enzyme-catalysed substrate reactions and also the Monod equation for microbial growth. The number of interacting active sites on an enzyme molecule is an additional parameter in this case. In this article, the cooperative growth model for n interacting sites on the enzyme is derived and compared with the classical Monod model.","PeriodicalId":15255,"journal":{"name":"Journal of biochemical toxicology","volume":"13 1","pages":"704-707"},"PeriodicalIF":0.0,"publicationDate":"2007-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73908666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
The filtration characteristics of yeast 酵母的过滤特性
Journal of biochemical toxicology Pub Date : 2007-05-29 DOI: 10.1002/JBT.2570270115
A. Rushton, H. E. Khoo
{"title":"The filtration characteristics of yeast","authors":"A. Rushton, H. E. Khoo","doi":"10.1002/JBT.2570270115","DOIUrl":"https://doi.org/10.1002/JBT.2570270115","url":null,"abstract":"The filtration characteristics of yeast cells are reported and the use of the information in process calculations of filtration rates is demonstrated. Comparison is made between filtration properties obtained by vacuum filtration studies and permeability measurements. The kinetics of cell growth are followed by size distribution records.","PeriodicalId":15255,"journal":{"name":"Journal of biochemical toxicology","volume":"264 1","pages":"99-109"},"PeriodicalIF":0.0,"publicationDate":"2007-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84665053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 10
Saccharification of bagasse pith 蔗渣髓的糖化
Journal of biochemical toxicology Pub Date : 2007-05-29 DOI: 10.1002/JBT.2570270606
Charles I. Nee, W. Yee
{"title":"Saccharification of bagasse pith","authors":"Charles I. Nee, W. Yee","doi":"10.1002/JBT.2570270606","DOIUrl":"https://doi.org/10.1002/JBT.2570270606","url":null,"abstract":"Work is reported here on a process for the saccharification of bagasse pith, as the second part of a study of bagasse processing aimed at establishing an integrated industry. A method for pentose preparation from bagasse pith is designed on the basis of the conclusions reached in the first part of the study. It is preferable to Scholler's process in recovery of sugar and in concentration of the sugar solution. A process for glucose production from pentose-exhausted cellulosic residue is also developed to avoid the difficulties encountered in the Udic-Rheinau process. It seems to be a promising continuous process capable of giving a higher yield of glucose with less acid at a higher speed and affording favourable conditions for crystallising the dissolved glucose.","PeriodicalId":15255,"journal":{"name":"Journal of biochemical toxicology","volume":"54 1","pages":"662-666"},"PeriodicalIF":0.0,"publicationDate":"2007-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85477923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Hardened alite pastes of various porosities. I. Degree of hydration, compressive strength and total porosity 硬化各种孔隙度的石灰糊。1 .水化程度、抗压强度和总孔隙率
Journal of biochemical toxicology Pub Date : 2007-05-29 DOI: 10.1002/JBT.2570270155
S. Abo-El-Enein, S. Goto, R. Kondo, R. Mikhail
{"title":"Hardened alite pastes of various porosities. I. Degree of hydration, compressive strength and total porosity","authors":"S. Abo-El-Enein, S. Goto, R. Kondo, R. Mikhail","doi":"10.1002/JBT.2570270155","DOIUrl":"https://doi.org/10.1002/JBT.2570270155","url":null,"abstract":"The alite used in this investigation was synthesised from the stoichiometric mixture at 1550°C. The hardened alite pastes were made using initial water/alite ratios of 0.20, 0.30, 0.45 and 0.60. Degree of hydration, compressive strength and total porosity were estimated at various hydration time intervals of 0.5 h, 2 h, 6 h, 1 day, 3 days, 7 days and 28 days. A meaningful relation between compressive strength and water/alite ratio was established at constant values of degree of hydration, total porosity and Powers' gel-space ratio.","PeriodicalId":15255,"journal":{"name":"Journal of biochemical toxicology","volume":"25 1","pages":"375-381"},"PeriodicalIF":0.0,"publicationDate":"2007-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84643791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Spectroscopic investigation of some derivatives of oxycellulose in cadoxen solution 氧纤维素在牛蒡溶液中的一些衍生物的光谱研究
Journal of biochemical toxicology Pub Date : 2007-05-29 DOI: 10.1002/JBT.2570270130
H. Blair, R. Cromie
{"title":"Spectroscopic investigation of some derivatives of oxycellulose in cadoxen solution","authors":"H. Blair, R. Cromie","doi":"10.1002/JBT.2570270130","DOIUrl":"https://doi.org/10.1002/JBT.2570270130","url":null,"abstract":"Condensation methods for the estimation of carbonyl groups in oxycellulose are briefly reviewed. The u.v. absorption spectra of solutions of oxycellulose and some of its derivatives in cadoxen have been examined. The results show that solutions of oxycellulose, its semicarbazide derivative and its thiosemicarbazide derivative are unsatisfactory for the spectrophotometric determination of carbonyl content, whereas the phenylhydrazine derivative may be used for an approximate determination; p-nitrophenylhydrazine however is shown to be an excellent reagent for this determination.","PeriodicalId":15255,"journal":{"name":"Journal of biochemical toxicology","volume":"8 1","pages":"205-213"},"PeriodicalIF":0.0,"publicationDate":"2007-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87305441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 6
Effect of moisture content of raw materials on the viscosity of limestone–marl slurry 原料含水率对灰泥浆粘度的影响
Journal of biochemical toxicology Pub Date : 2007-05-29 DOI: 10.1002/jbt.2570270106
K. M. Hanna, A. Gamal
{"title":"Effect of moisture content of raw materials on the viscosity of limestone–marl slurry","authors":"K. M. Hanna, A. Gamal","doi":"10.1002/jbt.2570270106","DOIUrl":"https://doi.org/10.1002/jbt.2570270106","url":null,"abstract":"Viscosity measurements were performed to investigate the effect of moisture contained in Portland cement raw materials on the flow characteristics of limestonemarl slurry. Under conditions of constant total water content, the fluidity of the slurry increased as the moisture content of the raw materials decreased. The effect of moisture content of the raw materials becomes significant on reducing the water content of the slurry. In the presence of slurry thinners, the extent of deflocculation is greater with the raw materials of lower moisture content.","PeriodicalId":15255,"journal":{"name":"Journal of biochemical toxicology","volume":"43 1","pages":"30-32"},"PeriodicalIF":0.0,"publicationDate":"2007-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75731712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Thermodynamic properties of the n-hexane and benzene system at elevated temperatures 高温下正己烷-苯体系的热力学性质
Journal of biochemical toxicology Pub Date : 2007-05-29 DOI: 10.1002/JBT.2570270113
M. Medani, M. A. Hasan
{"title":"Thermodynamic properties of the n-hexane and benzene system at elevated temperatures","authors":"M. Medani, M. A. Hasan","doi":"10.1002/JBT.2570270113","DOIUrl":"https://doi.org/10.1002/JBT.2570270113","url":null,"abstract":"The total vapour pressure and the composition of the liquid of the n-hexane and benzene mixtures have been measured under equilibrium conditions at 90, 110, 130, 150, 170 and 190°C. The corresponding vapour phase compositions were estimated using an expression of the liquid phase activity coefficient as a function of composition of the liquid phase. Several expressions were compared and the three-constant Redlich and Kister equation was found to give the best fit to the experimental vapour pressure data. The virial equation of state as well as a modified Redlich and Kwong equation were used to express the deviation of the vapour phase from the ideal. Results were compared and the discrepancy was found to be within the experimental tolerance. The low values of the liquid phase activity coefficients indicated that the behaviour of this particular system was not far from ideal. Also, it was found that the degree of deviation from the ideal decreased with the increase in temperature. The excess Gibbs free energy of mixing was calculated and it was found to be non-symmetrical with liquid composition. On increasing the temperature of the system, the liquid composition corresponding to the maximum GE tended to shift to a lower n-hexane concentration, while at fixed liquid composition, GE initially decreased and then remained stationary or increased again. This was thought to be due to differences in the molar volumes of the two components.","PeriodicalId":15255,"journal":{"name":"Journal of biochemical toxicology","volume":"96 1","pages":"80-92"},"PeriodicalIF":0.0,"publicationDate":"2007-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75979910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
Analysis of cell metabolic products and fermentation gases by gas chromatography 用气相色谱法分析细胞代谢产物和发酵气体
Journal of biochemical toxicology Pub Date : 2007-05-29 DOI: 10.1002/JBT.2570270122
P. Unger, Z. Vozňáková, J. Páca
{"title":"Analysis of cell metabolic products and fermentation gases by gas chromatography","authors":"P. Unger, Z. Vozňáková, J. Páca","doi":"10.1002/JBT.2570270122","DOIUrl":"https://doi.org/10.1002/JBT.2570270122","url":null,"abstract":"A method for the estimation of ethanol and volatile fatty acids by gas chromatography by direct treatment of cultivation broth is described. The packing material was Hallcomid M-18 with 1% H3PO4 on Chromosorb W AW. The separation was made at 132°C with nitrogen as a carrier gas; for detection a flame ionisation detector was used. The analysis of oxygen and carbon dioxide of the inlet and outlet gas from a fermentor was also studied. For the separation of the gases the combination of molecular seive 5A and Chromosorb 102 was used. The analysis was performed at 35°C with helium as a carrier gas and a thermal conductivity detector was used. With the experimental conditions found in this study the methods described gave reproducible and accurate results for the analytical control of cell cultivation processes.","PeriodicalId":15255,"journal":{"name":"Journal of biochemical toxicology","volume":"27 1","pages":"150-154"},"PeriodicalIF":0.0,"publicationDate":"2007-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73995660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 13
Liquefaction of lignohemicellulosic waste by processing with carbon monoxide and water 用一氧化碳和水处理木质素半纤维素废料的液化
Journal of biochemical toxicology Pub Date : 2007-05-29 DOI: 10.1002/JBT.2570270304
H. El-saied
{"title":"Liquefaction of lignohemicellulosic waste by processing with carbon monoxide and water","authors":"H. El-saied","doi":"10.1002/JBT.2570270304","DOIUrl":"https://doi.org/10.1002/JBT.2570270304","url":null,"abstract":"We have liquefied lignohemicellulose, from waste black liquor, by using a carbon monoxide and water process, without using carrier oil or catalyst and aiming to produce heavy oil. Most of the liquefying reactions seem to be essentially complete in about 10 min, under the optimum conditions. Increasing the reaction temperature from 250 to 440°C raises the yield of the heavy oil from 20 to 80%. At relatively low temperatures, the same high yield of the oil was obtained by addition of different alkalis to the reaction medium in a low concentration. With addition of calcium hydroxide at a Ca/C mole ratio of 6 × 10−3 (where Cas moles of added calcium and C is moles of organic carbon in the lignohemicellulose) the yield of the heavy oil was 80%, which was about 49% without any additives and at the same reaction conditions. The grass lignin gave higher yield than the woody lignin, obtained from cotton stalks. For benzene soluble products, which were obtained from liquefaction of lignohemicellulose, the atomic H/C ratio was high and had values of 1.0 to 1.3.","PeriodicalId":15255,"journal":{"name":"Journal of biochemical toxicology","volume":"74 1","pages":"443-452"},"PeriodicalIF":0.0,"publicationDate":"2007-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86916026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 8
Production of food yeast from whey ultrafiltrate by dialysis culture 乳清超滤液透析培养生产食品酵母
Journal of biochemical toxicology Pub Date : 2007-05-29 DOI: 10.1002/JBT.2570270124
A. Lane
{"title":"Production of food yeast from whey ultrafiltrate by dialysis culture","authors":"A. Lane","doi":"10.1002/JBT.2570270124","DOIUrl":"https://doi.org/10.1002/JBT.2570270124","url":null,"abstract":"Yeast (Kluyveromyces fragilis) concentrations up to 90 g dry weight/litre were obtained by dialysis culture in an 8 litre fermenter and the concentrations of lactose in the whey ultrafiltrate reservoirs were reduced to 5–8 g/litre during the cultivation period. A marked and progressive fall in cell yield was observed as the concentration of yeast increased. Modelling experiments indicated that this fall was consistent with the effects of maintenance energy requirements and that the effect could be minimised by a four-fold increase in the rate of dialysis. The feasibility of achieving the required increase with improved membranes was confirmed in experiments in which the rate of dialysis using existing membranes was shown to be doubled by either prior enzymic hydrolysis of the lactose or by doubling the membrane area.","PeriodicalId":15255,"journal":{"name":"Journal of biochemical toxicology","volume":"1 1","pages":"165-169"},"PeriodicalIF":0.0,"publicationDate":"2007-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83665330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 9
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