title: Influence of anaerobiosis and low temperature on Bacillus cereus growth, metabolism, and membrane properties.
abstract: The impact of simultaneous anaerobiosis and low temperature on growth parameters, metabolism, and membrane properties of Bacillus cereus ATCC 14579 was studied. No growth was observed under anaerobiosis at 12°C. In bioreactors, growth rates and biomass production were drastically reduced by simultaneous anaerobiosis and low temperature (15°C). The two conditions had a synergistic effect on biomass reduction. In anaerobic cultures, fermentative metabolism was modified by low temperature, with a marked reduction in ethanol production leading to a lower ability to produce NAD(+). Anaerobiosis reduced unsaturated fatty acids at both low optimal temperatures. In addition, simultaneous anaerobiosis and low temperatures markedly reduced levels of branched-chain fatty acids compared to all other conditions (accounting for 33% of total fatty acids against more 71% for low-temperature aerobiosis, optimal-temperature aerobiosis, and optimal-temperature anaerobiosis). This corresponded to high-melting-temperature lipids and to low-fluidity membranes, as indicated by differential scanning calorimetry, 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence anisotropy, and infrared spectroscopy. This is in contrast to requirements for cold adaptation. A link between modification in the synthesis of metabolites of fermentative metabolism and the reduction of branched-chain fatty acids at low temperature under anaerobiosis, through a modification of the oxidizing capacity, is assumed. This link may partly explain the impact of low temperature and anaerobiosis on membrane properties and growth performance.
authors.affiliation: INRA, UMR408 Sécurité et Qualité des Produits d’Origine Végétale, Avignon, France. benoit.desarrau@avignon.inra.fr
authors.forename: Benoît
authors.initials: B
authors.lastname: de Sarrau
authors.forename: Thierry
authors.initials: T
authors.lastname: Clavel
authors.forename: Caroline
authors.initials: C
authors.lastname: Clerté
authors.forename: Frédéric
authors.initials: F
authors.lastname: Carlin
authors.forename: Christian
authors.initials: C
authors.lastname: Giniès
authors.forename: Christophe
authors.initials: C
authors.lastname: Nguyen-The
mesh_terms: D000693:Anaerobiosis; D001409:Bacillus cereus / Q000254:growth & development* / Q000378:metabolism* / Q000528:radiation effects; D018533:Biomass; D019149:Bioreactors; D002151:Calorimetry; D002462:Cell Membrane / Q000378:metabolism* / Q000528:radiation effects; D003080:Cold Temperature; D000431:Ethanol / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D005285:Fermentation / Q000528:radiation effects; D005454:Fluorescence Polarization; D009243:NAD / Q000096:biosynthesis; D013055:Spectrophotometry, Infrared
chemical_list: D005231:Fatty Acids, Unsaturated; D009243:NAD; D000431:Ethanol