SUMMARY Sodium azide, 2,4-dinitrophenol and iodoacetate did not inhibit hydrolysis of lactose by cell-free preparations of Sacchuromyces fragilis ,8-galactosidase, but with intact organisms fermentation and hydrolysis were inhibited to a similar extent. This suggests that these inhibitors may interfere with the transport of lactose into the cell. Galactose fermentation was inhibited by sodium a...

This study focused on arsenate removal by nano zero-valent iron (NZVI) in the gas-bubbled aqueous solution. It appears that solution acidified by H2SO4 is far more favorable than by CO2-bubbled acidification. In addition, as dissolved oxygen was stripped out of solution by N2 gas bubbling, the arsenate removal dropped significantly. To take advantages of common practice of carbonation and oxic ...

In this study, a solid solution of arsenical ammonium-sodium jarosite, with the approximate formula [(NH4)0.72 Na0.06(H3O)0.21]Fe3(2.52)(SO4)1.85 (AsO4)0.15 [(OH)4.41 (H2O)1.59], was synthesized. The precipitate particle main size 38 µm, spherical morphology. A decomposition reaction in alkaline media carried out; comprised three stages: an induction period, progressive conversion and stabiliza...

27 In the present study, the effect of phosphate ion and iron hydroxides (Fe-plaques) on the 28 selective uptake of arsenic species by water fern (Salvinia natans L.) was investigated. The 29 plants were grown for 5 days in aqueous Murashige and Skoog (MS) culture media modified in 30 arsenic and phosphate concentrations. Arsenic accumulations in Salvinia natans L. increased 31 with the increas...

We report a novel pathway for arsenic detoxification in the legume symbiont Sinorhizobium meliloti. Although a majority of ars operons consist of three genes, arsR (transcriptional regulator), arsB [As(OH)3/H+ antiporter], and arsC (arsenate reductase), the S. meliloti ars operon includes an aquaglyceroporin (aqpS) in place of arsB. The presence of AqpS in an arsenic resistance operon is intere...

In this study arsenate [As(V)] removal from drinking water by coagulation process was investigated. Ferric chloride (FeCl3.6H2O) and ferrous sulfate (FeSO4.7H2O) were used as coagulant. The effects of major operating variables such as coagulant dose (1–30 mg/L) and pH (5.5–9.5) were investigated. Ferric chloride and ferrous sulfate were found as effective and reliable coagulant due to required ...

Ochreous precipitates containing 5.5-69.8 g/kg As were isolated from mine drainage in Finland and were composed of schwertmannite, ferrihydrite, and goethite. Schwertmannite formation was favored at pH 3-4, but its structure was degraded at high As levels. A series of coprecipitates were therefore prepared from mixed iron arsenate/sulfate solutions to define the limits of schwertmannite stabili...

Escherichia coli cells treated with arsenate cannot tumble. The relationship between cellular adenosine 5'-triphosphate (ATP) level and the ability to tumble has been studied. (i) Cells incubated with arsenate completely lost their tumbling ability, and the cellular ATP level was decreased to less than 0.3 nmol/mg of protein. (ii) Incubation with 10 mM arsenate-1 mM phosphate reduced the cellul...

Highly toxic arsenate occurs naturally in some well water as well as in industrial wastewaters. Removal of arsenate (As(V)) by biosorption with acid-washed crab shells (AWCS) is very sensitive to solution pH. It greatly increased when the solution pH was lowered from 3.44+/-0.07 to 2.51+/-0.02, but it was reduced at pH below 1.99+/-0.01. Change of solution pH not only affected the charged funct...