A method for preparing highly purified glutaminase (EC 3.5.1.2, L-glutamine amidohydrolase) from pig renal cortex is described. The main steps consist of sodium sulfate fractionation followed by alternative solubilization by dialysis against Tris-HCI buffer and precipitation with phosphateborate. The linal enzyme preparation contains no impurities which could be detected by sucrose gradient cen...

A new plate method was developed for rapid screening of Ketogulonicigenium vulgare mutants overproducing 2-keto-l-gulonic acid (2-KLG). The screening methodology took the advantage of the acidity caused by 2-KLG, which changes the color of bromothymol blue (pH indicator) from blue to yellow. Using the proposed method, a mutant, K. vulgare 65, was selected from 20,000 colonies produced by a stra...

This paper demonstrates local pH measurement in a microchip using a pH-sensing gel-microbead. To achieve this, the gel-microbead made of a hydrophilic photo-crosslinkable resin was functionalized with the pH indicator bromothymol blue (BTB). The primary constituent of this photo-crosslinkable resin is poly(ethylene glycol). Gel-microbeads impregnated with BTB were obtained by stirring the mixtu...

A direct, extraction-free spectrophotometric method has been developed for the determination of acebutolol hydrochloride (ABH) in pharmaceutical preparations. The method is based on ionpair complex formation between the drug and two acidic dyes (sulphonaphthalein) namely bromocresol green (BCG) and bromothymol blue (BTB). Conformity to Beer’s law enabled the assay of the drug in the range of 0....

A flow injection method for the determination of readily assimilable nitrogen (r.a.n.), i.e. ammonium and aminated nitrogen, is reported. The difference in pH of the sample in the presence and absence of formaldehyde, which blocks the amino function, provides the value of r.a.n. by monitoring the changes in absorbance of bromothymol blue at 616 nm. The detection and quantification limits are 10...

A flow system with a multi-channel peristaltic pump placed before the solenoid valves is proposed to overcome some limitations attributed to multi-commuted flow injection systems: the negative pressure can lead to the formation of unwanted air bubbles and limits the use of devices for separation processes (gas diffusion, dialysis or ion-exchange). The proposed approach was applied to the colori...

Multimode polymer waveguides and fiber-to-waveguide couplers have been integrated with microfluidic channels by use of a single-mask-step procedure, which ensured self-alignment between the optics and the fluidics and allowed a fabrication and packaging time of only one day. Three fabrication procedures for obtaining hermetically sealed channels were investigated, and the spectrally resolved pr...

A local pH measurement around cell by pH sensing gel-tool with adhesivecontrollability was developed. We fabricated gel-tool impregnated with pH indicator Bromothymol blue (BTB), which is used for pH measurement in neutral range. Adhesion of the gel-tool to objects such as glass, gel-tool and cell is performed by UV illumination in an electrolyte solution of a certain concentration. Gel-tool is...