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Owing to increasing amounts of xanthan and gellan in food, cosmetics and pharmaceuticals, as well as in some technical spheres, studies were carried out on the xanthan and gellan degrading bacteria present in activated sludge. The activated sludge used in the study was able to degrade both carbohydrates over 7 days, with levels of xanthan and gellan utilizing microbes estimated at 10(5) cells/g of dry sludge weight. Isolating key degrading bacteria revealed the important role of genus Paenibacillus in xanthan degradation and prosthecate bacterium Verrucomicrobium sp. GD, which was capable of gellan utilization. Further tests performed with both strains showed they were able to degrade other types of carbohydrate polymers, and that Verrucomicrobium sp. GD did not possess extracellular free gellan depolymerase.

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N-methyl-2-pyrrolidone (NMP) is a widely used solvent for many organic compounds and a component found in a vast array of chemical preparations. For this research paper, NMP degrading bacteria were isolated from two samples of activated sludge. They pertained to both Gram-negative and Gram-positive members, and belong to the Pseudomonas, Paracoccus, Acinetobacter and Rhodococcus genera. All the strains utilized 300 mg/L of NMP as the only source of carbon, energy and nitrogen over several days, and they were shown to additionally be able to degrade N-acetylphenylalanine (NAP). The growth of all the isolated strains was recorded at different NMP concentrations, to a maximum of 20 g/L.

A modified semimicro method is described for determining chemical oxygen demand (COD) employing microwave (MW) digestion (0.5 min exposure at 1,000 W power, and 10 min exposure at 250 W power) with a titration assessment. Composition of reaction mixture was the same as that of the usual reflux method. Determination was performed in glass vessels of original tetrafluoromethoxil containers. Under given conditions dichromate autoreduction was low. A good agreement with the usual reflux method was obtained with selected substances (potassium hydrogen phthalate, glutamic acid, glucose, dodecyl sulphate, where COD-MW/ThOD is 98.9-101.5%). With real samples (municipal sewage, mixed tanning and chemical wastewaters, and treated wastewater from biological treatment plants) the obtained results were also satisfactory (88.0-111.9%).