Showing papers by "Franz Schinner published in 1992"

Solubilization of inorganic phosphates by microorganisms isolated from forest soils

Abstract: Two strains (a Penicillium sp. and a Pseudomonas sp.) having high abilities to solubilize inorganic phosphates (hydroxylapatite and calcium hydrogenphosphate dihydrate) were screened from 600 colonies isolated from forest soils. Some of their physiological properties (nutrition, O 2 -demand, temperature) were investigated. It was possible to distinguish between solubilization through release of organic acids and still unknown mechanisms. Artificial acidification of the culture medium with HCl did not cause considerable P solubilization compared with our two isolates. In nonsterile soil both organisms caused a marked increase in the P fraction extracted with Licl solution.

Solubilization of zinc oxide from filter dust with Penicillium simplicissimum : bioreactor leaching and stoichiometry

Abstract: Filter dusts from metal-processing industries contain valuable metals which should be recycled. Some disadvantages of conventional recycling methods can be avoided by applying biohydrometallurgical methods. Fungi are suitable for such processes because they are fairly resistant to heavy metals. Furthermore, leaching activity occurs in a pH range from 2 to 7. This is important because filter dusts generally raise the pH of the medium. Leaching of zinc from zinc oxide contained in filter dust was possible in a bioreactor (stirred tank reactor) especially constructed for this purpose

A comparison of extracellular proteases from three psychrotrophic strains of Pseudomonas fluorescens

Abstract: Extracellular proteases from three psychrotrophic strains of Pseudomonas fluorescens were purified and characterized. The cultivation temperature decisively influenced the excretion of protease into the medium. Highest enzyme production occurred at 10°C (one strain) or 20°C (two strains). The purified proteases showed a molecular weight between 47kDa and 51kDa, the pI values ranged from 7.8 to 7.4. All three proteases were characterized by several closely focused bands. Sensitivity to metalchelating agents indicates that P. fluorescens proteases are metalloproteases (EC 3.4.24). The pH optimum for azocaseinolytic activity was at pH 6-7, the temperature optimum was at 40-45°C. The apparent energies of activation were 36.9-38.0kJ mol-1. The proteases were thermolabile. By adding calcium ion an increasing thermostability was observed. SDS, urea and several metal ions inhibited proteolytic activities to different extents. Casein was the preferred substrate for the proteases. With casein concentrations up to 0.4-0.75% a Michaelis-Menten-type kinetics was observed, at higher casein concentrations a substrate inhibiton occurred. None of the proteases showed aminopeptidase activity.

The influence of rock powders on microbial activity of three forest soils

Abstract: To improve the quality of forest soils by applying basic rock powders tests were carried out in Vorarlberg (Austria) in 1987: in the vicinity of Moggers on Stagno-Mollic Gleysol under Abieti-Fagetum luzuletosum, in Nenzing on Calcaric Regosol and Cambisol under Abieti-Fagetum luzuletosum and in Montafon on Stagno-Dystric Gleysol under Homogyno-Piceetum. The effects of a low dosage of rock powder application on nitrification, basal respiration, microbial biomass, xylanase, phosphatase and protease activities, the amount of nitrate nitrogen (NO3−-N), and the soil pH were investigated. Additions of rock powder increased protease, NO3−-N content and pH, but decreased phosphatase in the Ah-horizon of the Stagno-Mollic Gleysol. After 3 years the Ah-horizon from the experimental site Nenzing showed statistically verified differences of all investigated parameters except xylanase. In the acid spruce forest soils of the Montafon site the rock powder had no statistically significant effect on microbiological parameters. Only the soil pH increased. It can be postulated that the application of rock powders furthered C- and N-mineralization. In the long run this affects the turnover of mineral nutrients in forest ecosystems. Der Einflus von Gesteinsmehlen auf die mikrobiologische Aktivitat von 3 Waldboden Im Jahre 1987 wurden Versuche mit basenreichen Gesteinsmehlen zur Bodenverbesserung in Waldstandorten Vorarlbergs (Osterreich) angelegt: im Raum Moggers auf Pseudogley unter Abieti-Fagetum luzuletosum. im Raum Nenzing auf Pararendzina und Braunerde unter Abieti-Fagetum luzuletosum und im Montafon auf Podsol-Pseudogley unter Homogyno-Piceetum. Untersucht wurde der Einflus einer geringen Gesteinsmehlapplikation auf die Nitrifikationsrate, CO2-Freisetzung, mikrobielle Biomasse, Xylanase-, Phosphatase- und Proteaseaktivitat, auf die Menge des Nitratstickstoffes (NO3−-N) und auf den pH-Wert. Die Zugabe von Gesteinsmehl erhohte im Ah-Horizont des Pseudogleys die Proteaseaktivitat, den Nitratgehalt und das pH, erniedrigte die Phosphataseaktivitat. Der Ah-Horizont bei Nenzing zeigte nach 3 Jahren gesicherte Unterschiede aller untersuchter Parameter, mit Ausnahme der Xylanaseaktivitat. In den sauren Fichtenboden der Flache Montafon bewirkte das Gesteinsmehl keinen statistisch gesicherten Einflus auf die mikrobiologischen Parameter. Nur der pH-Wert erhohte sich. Es wird angenommen, das eine Applikation von Gesteinsmehl die C- und N-Mineralisation fordert. Langerfristig erhoht dies den Umsatz von mineralogischen Nahrstoffen in Waldokosystemen.

Isotachophoretic analysis of the lipophilic cation tetraphenylphosphoniumbromide

Abstract: Tetraphenylphosphoniumbromide (TPP), a lipophilic cation used for the determination of plasma membrane potential, was quantified by isotachophoresis. The optimized leading electrolyte consisted of 10 mmol/l KOH as leading ion, supplemented with 0.5% hydroxy-ethylcellulose. The pH was adjusted to 9.5 with methionine. The terminating ion was 10 mmol/l tris(hydroxymethyl)-aminomethane (pH 9.2, adjusted with methionine). Leading ion concentrations of 10, 1 and 0.5 mmol/l respectively, showed nearly the same detection limits (2×10−11 mol of TPP). This detection limit allowed the quantitative determination of TPP down to a concentration of 2 μmol/l. Calibration curves in the range of 2×10−11 to 1.5×10−10 mol of TPP showed correlation coefficients greater than 0.95 (n=12; α=0.01).