Besprechungen

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Permeabilitätsversuche an der Kartoffelpflanze

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Einige zellphysiologische Beobachtungen anHookeria lucens (L.) Sm

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Besprechungen

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Zum Wasserhaushalt vonTillandsia recurvata L. undTillandsia usneoides L. auf Puerto Rico

Ohne ZusammenfassungHerrn Prof. Dr. A. Pisek (Innsbruck) zum 70. Geburtstage gewidmet.     

Blattbau und Salzhaushalt vonLaguncularia racemosa (L)Gaertn. f. und anderer Mangrovebäume auf Puerto Rico

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Influence of iron,phosphate and methyl viologen on glycerol fermentation of Clostridium butyricum

 The effect of methyl viologen addition, and iron and phosphate limitation on product distribution during glycerol fermentation of Clostridium butyricum DSM 5431 was investigated in continuous culture. Special attention was paid to the gaseous products H₂ and CO₂, which were measured on-line. In all three cases, an increased yield of 1,3-propanediol linked to a decreased hydrogen release was observed, indicating that a higher proportion of electrons was channelled from reduced ferredoxin towards NADH₂ production. The specific substrate consumption rates and the specific production rates revealed that this increase in propanediol yield was not obtained at the expense of glycolysis products but by an increased substrate conversion (overflow metabolism). The acetate/ butyrate ratio during glycerol fermentation was essentially influenced by the availability of iron. It was substantially increased when the culture turned from iron excess to iron-limited conditions. Therefore iron limitation proved to be a suitable means to achieve high 1,3-propanediol yields and to reduce butyrate formation. Received: 29 August 1995 / Accepted: 20 September 1995     

Untersuchungen über Strahlenschutz an Pflanzenzellen

Ohne ZusammenfassungResearch carried out with the support of the International Atomic Energy Agency.