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- Fredlund, E., et al.
(författare)
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Metabolite profiles of the biocontrol yeast Pichia anomala J121 grown under oxygen limitation
- 2004
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Ingår i: Applied Microbiology and Biotechnology. - : Springer. - 0175-7598 .- 1432-0614. ; 64:3, s. 403-409
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Tidskriftsartikel (refereegranskat)abstract
- The biocontrol yeast Pichia anomala J121 prevents mould growth during the storage of moist grain under low oxygen/high carbon dioxide conditions. Growth and metabolite formation of P. anomala was analyzed under two conditions of oxygen limitation: (a) initial aerobic conditions with restricted oxygen access during the growth period and (b) initial microaerobic conditions followed by anaerobiosis. Major intra- and extracellular metabolites were analyzed by high-resolution magic-angle spinning (HR-MAS) NMR and HPLC, respectively. HR-MAS NMR allows the analysis of major soluble compounds inside intact cells, without the need for an extraction step. Biomass production was higher in treatment (a), whereas the specific ethanol production rate during growth on glucose was similar in both treatments. This implies that oxygen availability affected the respiration and not the fermentation of the yeast. Following glucose depletion, ethanol was oxidized to acetate in treatment (a), but continued to be produced in (b). Arabitol accumulated in the culture substrate of both treatments, whereas glycerol only accumulated in treatment (b). Trehalose, arabitol, and glycerol accumulated inside the cells in both treatments. The levels of these metabolites were generally significantly higher in treatment (b) than in (a), indicating their importance for P. anomala during severe oxygen limitation/anaerobic conditions.
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- Druvefors, U., et al.
(författare)
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Efficacy of the biocontrol yeast Pichia anomala during long-term storage of moist feed grain under different oxygen and carbon dioxide regimens
- 2002
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Ingår i: FEMS yeast research (Print). - 1567-1356 .- 1567-1364. ; 2:3, s. 389-394
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Tidskriftsartikel (refereegranskat)abstract
- The yeast Pichia anomala inhibits the spoilage mold Penicillium roqueforti in laboratory experiments with high-moisture wheat in malfunctioning airtight storage. The ability of P. anomala to prevent mold growth during 14 months of grain storage was evaluated in outdoor silos with different air permeabilities. Freshly harvested wheat in 160-kg portions was inoculated with 102 colony-forming units (cfu) g-1 P. roqueforti, alone or together with 104 cfu g-1 P. anomala. During the first month P. anomala increased to about 106 cfu g-1 in the treated silos to reach 107 cfu g-1 after 9 months. Naturally occurring P. anomala in the untreated silos increased from 102 to about 103 cfu g-1 during the first month and reached the same level as the treated silos after 9 months. Oxygen levels were reduced below the detection limit within 1 day, while carbon dioxide levels increased to 80-90% during the first month. P. roqueforti did not grow in wheat treated with P. anomala, regardless of silo permeability, but had increased to 105 cfu g-1 in the untreated silos after 14 months of storage. © 2002 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.
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