Jordan D Dimitrov | Search PubMed

PubMed2004

Compact program resolves overlapping voltammetric peaks.

A simple self-contained program designed to separate overlapping peaks from electrochemical analyses is presented. Combining an original interactive way to define initial parameter estimates with nonlinear curve fitting based on the simplex method of optimization, it allows the user to resolve voltammograms consisting of 2 to 5 analytical peaks raised on a straight base line. The program provides highly intuitive interface, easy operation, and straightforward result documentation. A free package including the program, three data files and user instructions is available on request.

Journal Article↗

PubMed2004

Optimization of casein-based semisynthetic medium for growing of toxigenic Corinebacterium diphtheriae in a fermenter.

Diphtheria toxin is produced by growing Corinebacterium diphtheriae either in a semisynthetic casein-based medium or in the Pope-Lingood meat extract based medium. The World Health Organization advises the use of the semisynthetic one, as it has important advantages. Data on the composition of casein-based media and their ability to support high toxin production are not freely available. Important factors affecting toxin production during C. diphtheriae cultivation are the pH of the culture medium and the concentration of casein hydrolysate and of Fe2+. We established that the optimal pH for toxin production is 7.2. The highest yield of toxin was obtained using a casein hydrolysate concentration of 35.0 g/L and a Fe2+ concentration of 0.05-0.41 microg/mL. Under these conditions, diphtheria toxin with higher purity and yield compared with the batches obtained using the meat-based medium of Pope-Lingood was produced.

Caseins↗