bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of polyacrylamide on microbial density levels and biodegradability in waste‐activated sludge
Authors: Chu Ching‐Ping , Lee Duu‐Jong , Chang Bea‐Ven , Liao Chian‐Sen 
Published: January 2005

AbstractThis study addressed the possible role of polyelectrolyte flocculation on microbial density levels in a waste‐activated sludge. Such an effect is commonly ignored. Applying polyelectrolyte reduced the density level of coliform bacteria in the flocculated sludge. Polyelectrolyte also reduced the 5‐day biochemical oxygen demand of sludge, possibly retarding the subsequent biodegradation processes.© 2001 Society of Chemical Industry
Modelling shock loadings and starvation in the biofiltration of toluene and xylene
Authors: Métris Aline , Gerrard A Mark , Cumming Robert H , Weigner Pavel , Paca Jan 
Published: January 2005

AbstractThe response of biofilters to varying periods of starvation and to changes in inlet concentrations of a mixture of toluene and xylene have been tested in laboratory‐scale biofilters packed with a mixture of Perlite and compost. These results have been mathematically modelled taking the emission of carbon dioxide as a proxy for kinetics measurements. The use of CO2 is a more practical approach than that of kinetics based upon batch experiments on pure cultures. A simplification of Zarook's method, our model produced good outlet predictions given small changes in the inlet concentration of toluene and xylene. But for more stressful situations, like the resumption of the feed after periods of starvation, the use of carbon dioxide proved to be inappropriate as an indicator of the biomass activity, greatly overestimating biofilter performance. This suggested either the occurrence of cryptic growth (as a result of the stress inflicted on the biomass) or perhaps the utilisation of the compost as a carbon source.© 2001 Society of Chemical Industry
Biodegradation of quinoline in crude oil
Authors: Sugaya Kazuo , Nakayama Osamu , Hinata Naoyuki , Kamekura Koichi , Ito Akira , Yamagiwa Kazuaki , Ohkawa Akira 
Published: January 2005

AbstractRemoval of quinoline, which is typical of nitrogen‐containing compounds in crude oil, was achieved by a biodegradation reaction by Comamonas sp TKV3‐2‐1. The aerobic strain, Comamonas sp TKV3‐2‐1, which can grow utilizing quinoline as the sources of both carbon and nitrogen, degraded quinoline to 2‐hydroxyquinoline, finally to water‐soluble substances. The degradation reaction of 2‐hydroxyquinoline was revealed to be regarded as a rate‐limiting step controlling the overall reaction of biodenitrogenation process of quinoline in crude oil. The degradation rate of 2‐hydroxyquinoline in a stirred fermenter had a maximum of 211 mg 2‐hydroxyquinoline g‐cell−1 h−1 when the portion of crude oil in the reaction mixture, the cell concentration and the rotational speed of agitation impeller were 83.3%(v/v), 28.5 gdm−3 and 11.7 s−1, respectively. After the reaction was completed, the crude oil and the cell suspension could be separated efficiently by centrifuging. The possibility of constructing a bioprocess for removing quinoline in crude oil under storage is also discussed.© 2001 Society of Chemical Industry
Plasmid stability in a recombinant S cerevisiae strain secreting a bifunctional fusion protein
Authors: Altıntaş M Mete , Kırdar Betül , Önsan Z İlsen , Ülgen Kutlu Ö 
Published: January 2005

AbstractThe recombinant Saccharomyces cerevisiae strain, YPB‐G, producing and secreting Bacillus subtilis α‐amylase and Aspergillus awamori glucoamylase as a fusion protein yielded efficient utilisation of starch. A segregated population balance model has been used to determine the probability of plasmid loss and plasmid copy number. The kinetics of cell growth and product (fusion protein) formation were based on a genetically structured model. The predictions were compared with the experimental observations obtained for the unstable recombinant S cerevisiae cells in a 1.5 dm−3 batch bioreactor with 30 g dm3 initial starch under non‐aerated conditions. The main advantage of the present model is that three different genetic classes were defined on the basis of the existence of plasmid and of the expression of the enzymes, ie cells containing plasmids and expressing the gene product, x1; cells containing plasmids and but not expressing the gene product, x2; and cells without plasmids, x3. It is confirmed by this model that the cells without plasmids outgrow and dominate in the fermentation medium (2.27 g dm−3 vs 0.51 g dm−3) as more and more glucose becomes available by the degradation of starch.© 2001 Society of Chemical Industry
Production of p‐toluenesulfonic acid by sulfonating toluene with gaseous sulfur trioxide
Authors: Wu J C , Wang B H , Zhang D L , Song G F , Yuan J T , Liu B F 
Published: January 2005

AbstractToluene was sulfonated by gaseous sulfur trioxide to prepare p‐toluenesulfonic acid. The effects of reaction temperature and toluene conversion on the isomer selectivities and the dynamic viscosity of the reaction mixture in a well‐stirred tubular glass reactor of 4 cm diameter and 16 cm height were investigated. Lower selectivity to the m‐isomer was obtained at lower reaction temperature and lower conversion of toluene, whereas the selectivity to the p‐isomer seemed to be less affected by these parameters. With the increase in toluene conversion a sharp increase in viscosity of the reaction mixture was observed, which was attributed to the saturation of the toluenesulfonic acids dissolved in toluene. A pilot‐scale stainless steel jet loop reactor (JLR) of 0.3 m diameter and 4 m height with an external cooler was constructed and used for the continuous sulfonation of toluene. It was found that the JLR was very effective for the fast removal of the large amount of reaction heat, and selectivities to the p‐isomer around 85% and to the m‐isomer below 1.2% were obtained.© 2001 Society of Chemical Industry
Application of the accelerated shelf life testing method (ASLT) to study the survival rates of freeze‐dried Lactococcus starter cultures
Authors: Achour M , Mtimet N , Cornelius C , Zgouli S , Mahjoub A , Thonart Ph , Hamdi M 
Published: January 2005

AbstractThe survival rates of two freeze‐dried strains, Lactococcus lactis var diacetylactis and Lactococcus lactis var lactis, were evaluated using the Accelerated Shelf Life Testing (ASLT) method. The strains were initially isolated from a brand of a Tunisian fermented milk product. Lactococcus cell survival observed at higher temperatures was used to extrapolate to shelf life at a lower storage temperature of 4 °C. The apparent kinetics of the survival rate loss were estimated and the effect of storage temperature was quantified by determining the inactivation energies for various samples. The work has shown an overall higher survival rate of the strain Lactococcus lactis var diacetylactis. An average half‐life of a strain maintained at 25 °C was equal to about 7 days as compared with about 43 days at 4 °C. The addition of lyoprotectants such glycerol, saccharose and calcium carbonate to the drying medium, improved the survival of such bacteria.© 2001 Society of Chemical Industry
Diffusional properties of chitosan hydrogel membranes
Authors: Krajewska Barbara 
Published: January 2005

AbstractChitosan membranes were prepared by a solvent evaporation technique, followed by crosslinking with glutaraldehyde and coating with BSA. The effects of crosslinking and BSA coating on the pore structure of such prepared hydrogel chitosan membranes were determined. The diffusion rates of 12 non‐electrolytes ranging in molecular radius between 2.5 and 14 Å through the membranes were measured, and the results were interpreted in terms of the capillary pore model and free volume model of solute diffusional transport through hydrogel membranes. Glutaraldehyde crosslinking was found to reduce the membrane water content and consequently the membrane pore size and surface porosity, whereas further BSA coating brought about the opposite effect. The latter effect lessened with an increase in glutaraldehyde pretreatment of the membranes. The optimal chitosan membrane preparation, compromising between the solute flux and membrane stability and durability was obtained when the membranes were crosslinked with glutaraldehyde at concentrations between 0.01 and 0.1% (w/w). The knowledge of transport properties and of physical strength of the membranes is of importance for the development of chitosan‐based controlled release systems.© 2001 Society of Chemical Industry
Determination of potential methane production capacity of a granular sludge from a pilot‐scale upflow anaerobic sludge blanket reactor using a specific methanogenic activity test
Authors: Ince Orhan , Ince Bahar Kasapgil , Yenigun Orhan 
Published: January 2005

AbstractA 450 dm3 pilot‐scale upflow anaerobic sludge blanket (UASB) reactor was used for the treatment of a fermentation‐based pharmaceutical wastewater. The UASB reactor performed well up to an organic loading rate (OLR) of 10.7 kg COD m−3 d−1 at which point 94% COD removal efficiency was achieved. This high treatment efficiency did not continue, however and the UASB reactor was then operated at lower OLRs for the remainder of the study. Specific methanogenic activity (SMA) tests were, therefore, carried out to determine the potential loading capacity of the UASB reactor. For this purpose, the SMA tests were carried out at four different initial acetate concentrations, namely 500 mg dm−3, 1000 mg dm−3, 1500 mg dm−3 and 2000 mg dm−3 so that substrate limitation could not occur. The results showed that the sludge sample taken from the UASB reactor (OLR of 6.1 kg COD m−3 d−1) had a potential acetoclastic methane production (PMP) rate of 72 cm3 CH4 g−1 VSS d−1. When the PMP rate was compared with the actual methane production rate (AMP) of 67 cm3 CH4 g−1 VSS d−1 obtained from the UASB reactor, the AMP/PMP ratio was found to be 0.94 which ensured that the UASB reactor was operated using its maximum potential acetoclastic methanogenic capacity. In order to achieve higher OLRs with desired COD removal efficiencies it was recommended that the UASB reactor should be loaded with suitable OLRs pre‐determined by SMA tests.© 2001 Society of Chemical Industry
Activity of horseradish peroxidase in aqueous and reverse micelles and back‐extraction from reverse‐micellar phases
Authors: Motlekar Nuzhat A , Bhagwat Sunil S 
Published: January 2005

AbstractStudies on the activity of the enzyme horseradish peroxidase (HRP) have been carried out in micellar as well as reverse‐micellar media. The activity of the enzyme was studied in the presence of different classes of surfactants – ionic as well as non‐ionic. In aqueous media, the activity of the enzyme varied depending on whether the concentration of the surfactant used was above or below the critical micellar concentration (CMC). The enzyme was also studied in reverse‐micellar systems. HRP was introduced into the reverse micellar phase by the injection method and its activity within the reverse micelles was determined. The effect of water to surfactant ratio (Wo) on activity within reverse micelles was studied, and an almost two‐fold increase in activity was seen when the enzyme was encapsulated within reverse micelles of aqueous phase fractional hold‐up (ϕ) of 0.0072 (v/v) consisting of sodium bis‐(2‐ethylhexyl) sulfosuccinate (AOT) in isooctane at a Wo of 20. The activity of HRP was measured over a wide range of AOT concentrations having different Wo values. Back‐extraction of HRP from these reverse micelles was carried out at varying ionic strengths of phosphate buffer. Back extraction was found to be highest at pH 7.0 in 40 mol m−3 phosphate buffer and 100 mol m−3 sodium chloride.© 2001 Society of Chemical Industry
Hydrolysis of p‐nitrophenyl laurate in supercritical carbon dioxide: comparison of two different enzymes
Authors: Srivastava Shireesh , Madras Giridhar 
Published: January 2005

AbstractThe enzymatic hydrolysis of p‐nitrophenyl laurate (PNPL) to p‐nitrophenol (PNP) was studied in supercritical carbon dioxide using crude Hog Pancreas Lipase (HPL) and P roqueforti Lipase (PRL). The two enzymes were compared for their optimal activity temperatures and reaction kinetics. HPL had a higher optimal temperature (65 °C) and better yield (22.5%) compared with PRL whose optimal temperature was 50 °C with a 15.3% yield. This is considerably higher than the optimum temperature of 37 °C and yields of less than 1% observed in the aqueous medium.© 2001 Society of Chemical Industry
Dual solute adsorption of 2,4,6‐trichlorophenol and N‐[2‐(2,4,6‐trichlorophenoxy)propyl]amine on to activated carbon
Authors: Garner Ian A , Watson‐Craik Irene A , Kirkwood Ralph , Senior Eric 
Published: January 2005

AbstractThe capacities of four activated carbon types to adsorb both 2,4,6‐trichlorophenol (TCP) and N‐[2‐(2,4,6‐trichlorophenoxy)propyl]amine (BTS40348), as single‐ and dual‐solutes, at pH 4, 7 and 9, were evaluated by use of the Freundlich isotherm model. Coal‐based activated carbon type F400 was found to most strongly adsorb both compounds, with adsorption optima at pH 4 and 9 for TCP and BTS40348, respectively. In dual‐solute isotherms, the adsorptive capacity for each solute was reduced with pH, dictating which solute was most strongly adsorbed. Compared with these batch isotherms, F400 adsorptive capacity was reduced in flow‐through column studies. Activated carbon bioregeneration was studied but the adsorptive capacity of the flow‐through column did not increase, indicating that biologically‐mediated desorption of solute did not occur.© 2001 Society of Chemical Industry
Decomposition of H2O2 on activated carbon obtained from olive stones
Authors: Khalil Laila B , Girgis Badie S , Tawfik Tarek A M 
Published: January 2005

AbstractActivated carbons were prepared from olive oil solid wastes by treatment in different schemes: impregnation with H3PO4 followed by pyrolysis at 300–700 °C, by steam pyrolysis at 600–700 °C, or by conventional steam activation at 850 °C. Porosity characteristics were determined by analysis of nitrogen adsorption isotherms, and carbons of widely different properties and surface pH values were obtained. Decomposition of H2O2 in dilute unbuffered solution was followed by measuring evolved oxygen volumetrically. First‐order kinetics was followed, and the catalytic rate coefficients were evaluated. The carbons tested showed appreciable activity where evolved oxygen attained ≈10% of the stoichiometric amount in 1 h. The degree of decomposition showed inverse dependence on surface area, pore volume and mean pore dimensions. The chemical nature of the surface, rather than the porosity characteristics, was the principal factor in enhancing the disproportionation of H2O2 on the activated carbon surface.© 2001 Society of Chemical Industry
The effect of preparation method on the catalytic activity of amorphous aluminas in ethanol dehydration
Authors: Bakoyannakis Demetris N , Zamboulis Demetris , Stalidis George A , Deliyanni Eleni A 
Published: January 2005

AbstractThe known heterogeneous catalytic dehydration of ethanol on amorphous aluminium oxide samples was adopted as a measure of catalytic activity and selectivity. The aluminium oxide samples were prepared by hydrolysis of aluminium chloride using propylamine, as proton acceptor, in pure and mixed aqueous ethanolic and acetonic media, freeze dried and activated. The catalytic activity and selectivity of the samples was measured in the temperature range 623–698 K for various flow rates of ethanol. The apparent activation energies were calculated (53–78 kJ mol−1) and depended on the solvent used in the preparation of the aluminas. The effect of solvent medium on the activity and selectivity was discussed.© 2001 Society of Chemical Industry
Extraction and recovery of gold from KAu(CN)2 using cetyltrimethylammonium bromide microemulsions
Authors: Zhang Tian‐Xi , Huang Bao‐Gui , Zhou Wei‐Jin , Gao Hong‐Cheng , Chen Jing , Wu Ha‐Shen , Wu Jin‐Guang 
Published: January 2005

AbstractExtraction and stripping of KAu(CN)2 from alkaline solution by a w/o microemulsion formed with cetyltrimethylammonium bromide (CTAB) using 198Au(I) tracer has been investigated. Various parameters, such as the Au(I) concentration in aqueous phase, concentrations of halide ions, NH4SCN and thiodiethylene glycol in stripping solution as well as the relationship between water and Au(I) concentration in the organic phase in the extraction and stripping of Au(I) were studied. The results show that almost all of the Au(I) in the aqueous phase was extracted into the organic phase. The water content decreased significantly with an increase in Au(I) concentration in the organic phase, contrary to the results of a system with tributyl phosphate (TBP) as cosolvent. Almost all of the extracted Au(I) (∼98%) can be recovered with pure thiodiethylene glycol as the stripping agent, and ∼93% of the Au(I) is stripped with high concentrations of NH4SCN(>3.0 mol dm−3) or KI (>2.0 mol dm−3).© 2001 Society of Chemical Industry
Electrochemical oxidation of tannery wastewater
Authors: Rao N N , Somasekhar K M , Kaul S N , Szpyrkowicz L 
Published: January 2005

AbstractTannery wastewater was treated by an electrochemical oxidation method using Ti/Pt, Ti/PbO2 and Ti/MnO2 anodes and a Ti cathode in a two‐electrode stirred batch reactor. The changes in colour concentration, chemical oxygen demand (COD), ammonia (NH4+), sulfide and total chromium have been determined as a function of treatment time and applied current density. Gas chromatography–mass spectrometry (GC–MS) analysis, performed on the wastewater samples before and after treatment, as well as on foam samples, is reported. Anode efficiency, rate constants and energy consumption were estimated and discussed. The efficiency of Ti/Pt was 0.802 kgCOD h−1 A−1m−2 and 0.270 kgNH4+ h−1 A−1m−2, and the energy consumption was 5.77 kWh kg−1 COD and 16.63 kWh kg−1 of NH4+. The order of efficiency of anodes was found to be Ti/Pt ≫ Ti/PbO2 > Ti/MnO2. The results indicate that the electro‐oxidation method could be used for effective oxidation of tannery wastewater and a final effluent with substantially reduced pollution load can be obtained.© 2001 Society of Chemical Industry
Oil and fungal biomass dispersion in a stirred tank containing a simulated fermentation broth
Authors: Córdova‐Aguilar Ma Soledad , Sánchez Adriana , Serrano‐Carreón Leobardo , Galindo Enrique 
Published: January 2005

AbstractThe production of γ‐decalactone by the filamentous fungus Trichoderma harzianum involves four phases (oil–water–air–mycelium) and its dispersion is crucial during fermentation. Oil and biomass (when present) dispersion, as a function of the volumetric power drawn (P/V), was characterized, in two; three‐ and four‐phase systems agitated with Rushton turbines. Trichoderma harzianum mycelium was used as the solid phase in the four‐phase system. Two stages of the fermentation were simulated: the beginning (15% oil and 1.4 kgm−3 of mycelium) and the end (2% oil and 10.6 kg m−3 of mycelium). In the two‐phase system, the use of exhausted broth achieved higher oil dispersions at low P/V values as compared with distilled water. Aeration decreased the oil dispersion for the high‐oil system, but enhanced oil dispersion for the low‐oil system. Compared with the P/V used in the actual fermentation (0.2 kW m−3), a high segregation of the system was observed for the high‐oil/low‐biomass system, due to the difficulty of mixing the thick oil–air emulsion present at the top of the tank. The system simulating the end of the fermentation reached almost complete homogeneity of oil and biomass, a phenomenon due to the high biomass/oil ratio and the biomass acting as an oil carrier.© 2001 Society of Chemical Industry
Optimisation of the biological treatment of hypersaline wastewater fromDunaliella salinacarotenogenesis
Authors: Santos Carla A , Vieira Ana M , Fernandes Helena L , Empis Jose A , Novais Júlio M 
Published: January 2005

AbstractThe reutilisation ofDunaliella salinacarotenogenesis medium, after microalgal biomass separation by centrifugation, was assessed. The wastewater had an NaCl concentration between 174 g dm−3and 254 g dm−3and an average total organic matter concentration of 1540 mg dm−3ash‐free dry weight, of which 41% (w/v) was glycerol. The biological treatment was established at laboratory scale and batch operations used halophilic bacteria from the wastewater itself. The wastewater was supplemented with NH4+,PO43−, K+and Mg2+ions to enhance growth. The effect of each ion addedper sewas initially investigated and a response surface methodology (RSM) used to identify the optimal conditions for maximisation of glycerol removal from the wastewater, which was considered to be the main objective. Addition of NH4+ions alone achieved 79% glycerol removal compared with only 59% in the absence of supplement, after 8 days incubation. The combined addition of ions ([NaCl] = 214 g dm−3, [Mg2+] = 114 mg dm−3, [K+] = 131 mg dm−3, [NH4+] = 113 mg dm−3, [PO43−] = 40 mg dm−3) increased glycerol removal from the wastewater such that, after 2 days incubation, no residual glycerol was apparent in cultures. These ion combinations enabled the halophilic bacteria to efficiently remove glycerol from the wastewater and consequently reduce organic matter. This treated wastewater should be appropriate for reutilisation as a carotenogenesis medium for β‐carotene production fromD salina.© 2001 Society of Chemical Industry
Flow and mass transfer in aerated viscous Newtonian liquids in an unbaffled agitated vessel having alternating forward–reverse rotating impellers
Authors: Yoshida Masanori , Yamagiwa Kazuaki , Ito Akira , Ohkawa Akira , Abe Masahiko , Tezura Shuichi , Shimazaki Masuo 
Published: January 2005

AbstractFlow and mass transfer characteristics in aerated viscous Newtonian liquids were studied for an unbaffled aerated agitated vessel with alternating rotating impellers (AAVAI), ie with multiple forward–reverse rotating impellers having four delta blades. The effects of operating conditions such as gas sparging rate, agitation rate and the number of impeller stages, and the liquid physical properties (viscosity) on the gas hold‐up, ϕgD, and volumetric oxygen transfer coefficient, kLaD were evaluated experimentally. The dependences of ϕgD and kLaD on the specific total power input and superficial gas velocity differed, depending on the ranges of liquid viscosity. Empirical relationships are presented for each viscosity range to predict ϕgD and kLaD as a function of the specific total power input, superficial gas velocity and viscosity of liquid. Based on a comparative investigation of the volumetric coefficient in terms of the specific total power input between the AAVAI and conventional aerated agitated vessels (CAAVs) having unidirectionally rotating impellers, the usefulness of AAVAI as a gas–liquid agitator treating viscous Newtonian liquids is also discussed.© 2001 Society of Chemical Industry
Autotrophic nitrification and denitrification characteristics of an upflow biological aerated filter
Authors: Han Dong‐Woo , Yun Ho‐Joon , Kim Dong‐Jin 
Published: January 2005

AbstractWastewater nitrification was carried out using a laboratory‐scale upflow biological aerated filter (BAF) packed with a polyurethane‐based porous medium. The filtration medium has macro‐pores which provide a greater surface area for the development of biofilms. The macro‐pores have both aerobic and anaerobic zones, depending on the depth of oxygen penetration in the medium. Wastewater ammonium was oxidized at a maximum rate of 1.8 kg NH4+m−3d−1 and showed more than 90% nitrification efficiency in the BAF. During the biological nitrification of wastewater, considerable nitrogen loss was observed in the BAF under oxygen‐limited conditions when organic carbons were not provided for denitrification. Most probably, the lost nitrogen was converted to gaseous nitrogen compounds including dinitrogen by autotrophic dentrification and anaerobic ammonium oxidation.© 2001 Society of Chemical Industry