title: Water activity, temperature, and pH effects on growth of the biocontrol agent Pantoea agglomerans CPA-2.
abstract: The growth response of the biocontrol agent Pantoea agglomerans to changes in water activity (a(w)), temperature, and pH was determined in vitro in nutrient yeast extract-sucrose medium. The minimum temperature at which P. agglomerans was able to grow was 267-272 kelvins (-6 to -1 degrees C), and growth of P. agglomerans did not change at varying pH levels (4.5-8.6). The minimum a(w) for growth was 0.96 in media modified with glycerol and 0.95 in media modified with NaCl or glucose. Solute used to reduce water activity had a great influence on bacterial growth, especially at unfavourable conditions (e.g., low pH or temperature). NaCl stimulated bacterial growth under optimum temperatures but inhibited it under unfavourable pH conditions (4.5 or 8.6). In contrast, the presence of glucose in the medium allowed P. agglomerans to grow over a broad range of temperature (3-42 degrees C) or pH (5-8.6) regimes. This study has defined the range of environmental conditions (a(w), pH, and temperature) over which the bacteria may be developed for biological control of postharvest diseases.
authors.affiliation: Postharvest Unit, Centre de Recerca de Tecnología d'Aliments (CeRTA), Centre Universitat de Lleida, Institut de Recerca Tecnología Alimentaria (UdL-IRTA), 177 Rovira Roure Ave., 25198 Lleida, Spain. elena.costa@irta.es
authors.forename: E
authors.initials: E
authors.lastname: Costa
authors.forename: J
authors.initials: J
authors.lastname: Usall
authors.forename: N
authors.initials: N
authors.lastname: Teixidó
authors.forename: J
authors.initials: J
authors.lastname: Delgado
authors.forename: I
authors.initials: I
authors.lastname: Viñas
mesh_terms: D018533:Biomass; D002957:Citrus / Q000382:microbiology; D003470:Culture Media / Q000737:chemistry / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D020636:Pantoea / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D010572:Pest Control, Biological; D010935:Plant Diseases / Q000382:microbiology; D013696:Temperature; D014867:Water / Q000494:pharmacology*
chemical_list: D003470:Culture Media; D014867:Water