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Central carbon metabolism of the biocontrol yeast Pichia anomala

influence of oxygen limitation

Fredlund, Elisabeth (2004). Central carbon metabolism of the biocontrol yeast Pichia anomala. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae. Agraria, 1401-6249 ; 488
ISBN 91-576-6767-5
[Doctoral thesis]

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The biocontrol yeast Pichia anomala prevents mould damage of moist cereal grain during malfunctioning airtight storage but it can also spoil food and feed. This thesis focuses on the physiology and metabolism of P. anomala, in particular during oxygen limitation, a condition relevant to airtight storage of cereal grain. P. anomala grew under strictly anaerobic conditions, at temperatures between 3 and 37 degrees, pH values between 2.0 and 12.4, low water activity (0.85), and on many different nutrients. Accumulation of low-molecular compounds in living cells was analysed by HR MAS-NMR. Glycerol, arabitol, and trehalose accumulation increased with reduced oxygen availability, indicating a role during oxygen-limited growth. Regulation of the central aerobic and hypoxic metabolism of P. anomala was investigated under controlled fermentor conditions. Oxygen limitation induced alcoholic fermentation as well as activity of the key fermentative enzymes, ADH and PDC. Metabolic flux analysis revealed that the TCA pathway operated as a cycle during aerobic batch culture and as a two-branched pathway under oxygen limitation. Hypoxic conditions also increased the production of ethyl acetate, an ester involved in the biocontrol activity of P. anomala. Genes encoding the ADH and PDC enzymes were cloned, PaADH1, PaADH2, and PaPDC1, and their expression was analysed with real-time RT-PCR. PaADH1 and PaPDC1 were expressed during aerobic growth on glucose and ethanol and were up-regulated in response to oxygen limitation. PaADH2 expression was low during these growth conditions, i.e. <1% of the level of its isogene, PaADH1. In cells grown on succinate, the expression of the two ADH isogenes was the opposite, high expression of PaADH2 and low expression of PaADH1. The up-regulation of gene expression and enzyme activity did not quantitatively correlate with glycolytic flux. Thus, additional regulatory phenomena at the posttranscriptional and posttranslational level are important in the distribution of carbon through the respiratory and fermentative pathways.

Authors/Creators:Fredlund, Elisabeth
Title:Central carbon metabolism of the biocontrol yeast Pichia anomala
Subtitle:influence of oxygen limitation
Series Name/Journal:Acta Universitatis Agriculturae Sueciae. Agraria
Year of publishing :October 2004
Number of Pages:54
ALLI. Fredlund, E., Druvefors, U., Lingsten, K-J., Boysen, M. E., and Schnürer J. 2002. Physiological characteristics of the biocontrol yeast Pichia anomala J121. FEMS Yeast Res 2:395-402. II. Fredlund, E., Broberg, A., Boysen, M. E., Kenne, L., and Schnürer, J. 2004. Metabolite profiles of the biocontrol yeast Pichia anomala J121 grown under oxygen limitation. Appl Microb Biotech 64:403-409. III. Fredlund, E., Druvefors, U. Ä, Olstorpe Nilsson, M., Passoth, V., and Schnürer, J. 2004. Influence of ethyl acetate production and ploidy on the anti-mould activity of Pichia anomala. FEMS Microbiol Lett 238:133-137. IV. Fredlund, E., Blank, L., Schnürer, J., Sauer, U., and Passoth, V. 2004. Oxygen and glucose dependent regulation of central carbon metabolism in Pichia anomala. Appl Environ Microbiol. 70:5905-5911. V. Fredlund, E., Beerlage, C., Schnürer, J., and Passoth, V. Oxygen and carbon source-regulated expression of PDC and ADH genes in the respiratory yeast Pichia anomala. (manuscript).
Place of Publication:Uppsala
ISBN for printed version:91-576-6767-5
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:Q Food science > Q01 Food science and technology
Subjects:Not in use, please see Agris categories
Agrovoc terms:pichia, yeasts, metabolism, acetates, alcohol dehydrogenase, pyruvate decarboxylase, aldehydes, penicillium roquefortii
Keywords:Crabtree negative, acetate, alcohol dehydrogenase, pyruvate decarboxylase, aldehyde dehydrogenase, Penicillium roqueforti
Permanent URL:
ID Code:674
Department:(NL, NJ) > Dept. of Microbiology (until 161231)
Deposited By: Elisabeth Fredlund
Deposited On:28 Oct 2004 00:00
Metadata Last Modified:02 Dec 2014 10:06

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