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Title:
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Biological characterization of the biocontrol agent Bacillus amyloliquefaciens CPA-8: the effect of temperature, pH and water activity on growth, susceptibility to antibiotics and detection of enterotoxic genes
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Author:
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Gotor Vila, Amparo María; Teixidó i Espasa, Neus; Sisquella Sanagustín, María; Torres Sanchis, Rosario; Usall i Rodié, Josep
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Notes:
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This work focuses on the biological understanding of the biocontrol agent Bacillus amyloliquefaciens CPA-8 in order to accomplish the characterization required in the registration process for the development of a microorganism-based product. The tolerance of CPA-8 to grow under different pH–temperature and water activity (a w)–temperature conditions was widely demonstrated. Regarding the pH results, optimum growth at the evaluated conditions was observed at 37 °C and pH between 7 and 5. On the contrary, the slowest growth was recorded at 20 °C and pH 4.5. Moreover, the type of solute used to reduce a w had a great influence on the minimum a w at which the bacterium was able to grow. The lowest a w values for CPA-8 growth in media modified with glycerol and glucose were 0.950 and 0.960, respectively. Besides, the lowest a w for CPA-8 growth increased when the temperature decreased to 20 °C, at which CPA-8 was not able to grow at less than 0.990 a w, regardless of the type of solute. Antibiotic susceptibility tests were carried out to determine which antibiotic could affect the behavior of the bacteria and revealed that CPA-8 was clearly resistant to hygromycin. Finally, a PCR amplification assay to detect the presence of enterotoxic genes from Bacillus cereus in CPA-8 was also performed. CPA-8 gave negative results for all the genes tested except for nheA gene, which is not enough for the toxicity expression, suggesting that fruit treated with this antagonist will not be a potential vehicle for foodborne illnesses.
This research was supported by the European project BIOCOMES FP7-612713 and by the Secretaria d’Universitats i Recerca del Departament d’Economia i Coneixement de la Generalitat de Catalunya for the PhD Grant 2014-FI-B00367 (Amparo M. Gotor Vila). The authors also thank CERCA Program (Generalitat de Catalunya). |
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Subject(s):
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-Bacillus spp.
-Biocontrol
-Ecophysiology
-Enterotoxicity
-Sensibility to antibiotics |
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Rights:
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(c) Springer Science+Business Media, 2017
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Document type:
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article
acceptedVersion |
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Published by:
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Springer Verlag
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