排序方式: 共有13条查询结果,搜索用时 15 毫秒
1.
Digrazia Philip M. Blackburn James W. Bienkowski Paul R. Hilton Barry Reed Gregory D. King J. M. Henry Sayler Gary S. 《Applied biochemistry and biotechnology》1990,(1):237-252
An experimental and mathematical method is developed for the microbial systems analysis of polyaromatic hydrocarbon (PAH)-degrading
mixed cultures in PAH-contaminated “town gas” soil systems. Frequency response is the primary experimental and data analysis
tool used to probe the structure of these complicated systems. The objective is to provide a fundamental protocol for evaluating
the performance of specific mixed microbial cultures on specific soil systems by elucidating the salient system variables
and their interactions. Two well-described reactor systems, a constant volume stirred tank reactor (CSTR) and a plug flow
differential volume reactor, are used in order to remove performance effects that are related to reactor type as opposed to
system structure. These two reactor systems are well-defined systems that can be described mathematically and represent the
two extremes of one potentially important system variable, macroscopic mass transfer. The experimental and mathematical structure
of the protocol is described, experimental data is presented, and data analysis is demonstrated for the stripping, sorption,
and biodegradation of napththalene. 相似文献
2.
Karol Kraszewski Ireneusz Tomczyk Dr. Aneta Drabinska Dr. Krzysztof Bienkowski Dr. Renata Solarska Dr. Marcin Kalek 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(50):11584-11592
The oxidative dearomatization of phenols with the addition of nucleophiles to the aromatic ring induced by hypervalent iodine(III) reagents and catalysts has emerged as a highly useful synthetic approach. However, experimental mechanistic studies of this important process have been extremely scarce. In this report, we describe systematic investigations of the dearomatizing hydroxylation of phenols using an array of experimental techniques. Kinetics, EPR spectroscopy, and reactions with radical probes demonstrate that the transformation proceeds by a radical-chain mechanism, with a phenoxyl radical being the key chain-carrying intermediate. Moreover, UV and NMR spectroscopy, high-resolution mass spectrometry, and cyclic voltammetry show that before reacting with the phenoxyl radical, the water molecule becomes activated by the interaction with the iodine(III) center, causing the Umpolung of this formally nucleophilic substrate. The radical-chain mechanism allows the rationalization of all existing observations regarding the iodine(III)-promoted oxidative dearomatization of phenols. 相似文献
3.
Rouhana Nathalie Handagama Naresh Bienkowski Paul R. 《Applied biochemistry and biotechnology》1997,(1):809-821
A vapor-phase bioreactor has been developed utilizing porous metal membranes in a cylindrical design employing radial flow
as opposed to traditional axial flow for the vapor stream. The system was evaluated for the biodegradation ofp-xylene (p-xylene) from a water-saturated air stream byPseudomonas putida ATCC 23973 immobilized onto sand. The biocatalyst was placed in the annular space between two cylindrical, porous stainless-steel
membranes. Details of the reactor system are presented along with biological data verifying system performance. The feed flow
rate andp-xylene concentration were varied between 60 and 130 cm3/min and 15–150 ppm, respectively. Continuous reactor operation was maintained for 80–200 h with removal efficiencies (based
onp-xylene disappearance) between 80 and 95%. The effluent concentration histories were compared to determine the operating range
of the bioreactor. 相似文献
4.
Sun May Y. Nghiem Nhuan P. Davison Brian H. Webb Oren F. Bienkowski Paul R. 《Applied biochemistry and biotechnology》1998,(1):429-439
The production of ethanol from starch was studied in a fluidized-bed reactor (FBR) using co-immobilizedZymomonas mobilis and glucoamylase. The FBR was a glass column of 2.54 cm in diameter and 120 cm in length. TheZ. mobilis and glucoamylase were co-immobilized within small uniform beads (1.2-2.5 mm diameter) of κ-carrageenan. The substrate for
ethanol production was a soluble starch. Light steep water was used as the complex nutrient source. The experiments were performed
at 35κC and pH range of 4.0-5.5. The substrate concentrations ranged from 40 to 185 g/L, and the feed rates from 10 to 37
mL/min. Under relaxed sterility conditions, the FBR was successfully operated for a period of 22 d, during which no contamination
or structural failure of the biocatalyst beads was observed. Volumetric productivity as high as 38 g ethanol/(Lh), which was
74% of the maximum expected value, was obtained. Typical ethanol volumetric productivity was in the range of 15-20 g/(Lh).
The average yield was 0.49 g ethanol/g substrate consumed, which was 90% of the theoretical yield. Very low levels of glucose
were observed in the reactor, indicating that starch hydrolysis was the rate-limiting step. 相似文献
5.
Many nonvolatile organic compounds, e.g., polyaromatic hydrocarbons (PAHs), are readily stripped during aerobic biodegradation.
This is because of the high infinite dilution activity coefficient resulting from forces generated by the water-organic interactions
at the molecular level. Several models have been proposed for air-stripping based on the Henry’s law constant. By definition,
the Henry’s law constant is the infinite dilution activity coefficient multiplied by the pure component vapor pressure. In
this article, a gas saturation technique was used to measure the very low vapor pressures exhibited by these nonvolatile compounds.
Literature values of other PAHs have been tabulated and are presented. For determining infinite dilution activity coefficients,
a differential ebulliometery apparatus has been constructed. In this technique, the boiling point difference between pure
water and a water-organic solution is measured very precisely. Thermodynamics is then used to calculate the infinite dilution
activity coefficient. The method’s accuracy has been tested using the phenol-water system. 相似文献
6.
Enhanced Water Splitting at Thin Film Tungsten Trioxide Photoanodes Bearing Plasmonic Gold–Polyoxometalate Particles 下载免费PDF全文
Dr. Renata Solarska Krzysztof Bienkowski Dr. Sylwia Zoladek Aldona Majcher Dr. Tomasz Stefaniuk Prof. Pawel J. Kulesza Prof. Jan Augustynski 《Angewandte Chemie (International ed. in English)》2014,53(51):14196-14200
Tungsten trioxide (WO3) is one of a few stable semiconductor materials liable to produce solar fuel by photoelectrochemical water splitting. To enhance its visible light conversion efficiency, we incorporated plasmonic gold nanoparticles (Au NPs) derivatized with polyoxometalate (H3PMo12O40) species into WO3. The combined plasmonic and catalytic effect of Au NPs anchored to the WO3 surface resulted in a large increase of water photooxidation currents. Shielding the Au NPs with polyoxometalates appears to be an effective means to avoid formation of recombination centers at the photoanode surface. 相似文献
7.
Lackey L. W. Phelps T. J. Bienkowski P. R. White D. C. 《Applied biochemistry and biotechnology》1993,39(1):701-713
Applied Biochemistry and Biotechnology - Aliphatic chlorinated compounds, such as trichloroethylene (TCE) and tetrachloroethylene (PCE), are major contaminants of ground water. A single-pass... 相似文献
8.
Sun May Y. Bienkowski Paul R. Davison Brian H. Spurrier Merry A. Webb Oren F. 《Applied biochemistry and biotechnology》1997,63(1):483-493
Applied Biochemistry and Biotechnology - The performance of coimmobilizedSaccharomyces cerevisiae and amyloglucosidase (AG) was evaluated in a fluidized-bed reactor. Soluble starch and yeast... 相似文献
9.
Korde V. M. Phelps T. J. Bienkowski P. R. White D. C. 《Applied biochemistry and biotechnology》1993,39(1):631-641
Applied Biochemistry and Biotechnology - Ground-water contamination by chlorinated aliphatic compounds is a major cause for concern because of their toxicity. This study examined the biodegradation... 相似文献
10.
Paul R. Bienkowski Douglas D. Lee Charles H. Byers 《Applied biochemistry and biotechnology》1988,18(1):261-273
Antibiotic production is a complex capital intensive process, which divides naturally into two segments, fermentation and separation/purification. The separation and purification section is very large as a result of the number of processing steps required (up to 60) and the need to purify and recycle large quantities of organic solvents. Separation and purification is not generic within the antibiotic industry. Not only does each individual antibiotic require a different separation process, but also there are many different separation schemes in use for the same antibiotic. Much research is currently in progress on three relatively new separation techniques on a commercial level, which may lead to substantial reductions in the complexity of the process; chromatography (both conventional preparative HPLC and annular chromatography), supercritical extraction, and various membrane processes. 相似文献