Control of sulphide during anaerobic treatment of S-containing wastewaters by adding limited amounts of oxygen or nitrate

Sulphide generated during anaerobic treatment of S-containing wastewaters represents an environmental problem. Adding limited amounts of oxygen or nitrate (or nitrite) to biologically (or chemically) oxidise sulphide forms a simple process level strategy to control this problem. This short review evaluates the feasibility and limitations of this strategy on the basis of the results of bioreactor studies.Sulphide generated during anaerobic treatment of S-containing wastewaters represents an environmental problem. Adding limited amounts of oxygen or nitrate (or nitrite) to biologically (or chemically) oxidise sulphide forms a simple process level strategy to control this problem. This short review evaluates the feasibility and limitations of this strategy on the basis of the results of bioreactor studies.Spanish Ministry of Education and Science; AEA Technology Environment; Nova Energie; The Swedish Gas Centre; University of Southern Denmark

Clostridium lundense sp. nov., a novel anaerobic lipolytic bacterium isolated from bovine rumen

A strictly anaerobic, mesophilic, endospore-forming, lipolytic bacterium, designated strain R1T, was isolated from bovine rumen fluid and characterized. Cells of this isolate were Gram-positive, non-motile rods that formed spherical terminal spores. The overall biochemical and physiological characteristics indicated that this strain should be placed in the genus Clostridium. The strain grew at temperatures between 25 and 47 °C (optimum, 37 °C), at pH between 5·0 and 8·5 (optimum pH 5·5–7·0) and in NaCl concentrations of 0–3 % (w/v). The isolate was not able to utilize glucose or other carbohydrates as carbon sources. The DNA G+C content was 31·2 mol%. Sequence analysis of the 16S rRNA gene of R1T revealed that it has the closest match (98 % similarity) with Clostridium tetanomorphum DSM 4474T. The highest levels of DNA–DNA relatedness of the isolate were 61·9 and 54·3 % with Clostridium pascui DSM 10365T and C. tetanomorphum DSM 4474T, respectively. Based on 16S rRNA gene sequence similarity, phylogenetic analysis, DNA G+C content, DNA–DNA hybridization data and distinct phenotypic characteristics, strain R1T (=DSM 17049T=CCUG 50446T) was classified in the genus Clostridium, as a member of a novel species, for which the name Clostridium lundense sp. nov. is proposed.Fil: Cirne, Dores G.. Lund University; SueciaFil: Delgado, Osvaldo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Marichamy, Sankar. Lund University; SueciaFil: Mattiasson, Bo. Lund University; Sueci