title: Identification and quantification of antifungal compounds produced by lactic acid bacteria and propionibacteria.
abstract: Fungal growth in bakery products represents the most frequent cause of spoilage and leads to economic losses for industrials and consumers. Bacteria, such as lactic acid bacteria and propionibacteria, are commonly known to play an active role in preservation of fermented food, producing a large range of antifungal metabolites. In a previous study (Le Lay et al., 2016), an extensive screening performed both in vitro and in situ allowed for the selection of bacteria exhibiting an antifungal activity. In the present study, active supernatants against Penicillium corylophilum and Aspergillus niger were analyzed to identify and quantify the antifungal compounds associated with the observed activity. Supernatant treatments (pH neutralization, heating and addition of proteinase K) suggested that organic acids played the most important role in the antifungal activity of each tested supernatant. Different methods (HPLC, mass spectrometry, colorimetric and enzymatic assays) were then applied to analyze the supernatants and it was shown that the main antifungal compounds corresponded to lactic, acetic and propionic acids, ethanol and hydrogen peroxide, as well as other compounds present at low levels such as phenyllactic, hydroxyphenyllactic, azelaic and caproic acids. Based on these results, various combinations of the identified compounds were used to evaluate their effect on conidial germination and fungal growth of P. corylophilum and Eurotium repens. Some combinations presented the same activity than the bacterial culture supernatant thus confirming the involvement of the identified molecules in the antifungal activity. The obtained results suggested that acetic acid was mainly responsible for the antifungal activity against P. corylophilum and played an important role in E. repens inhibition.
authors.affiliation: Université de Brest, EA 3882, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, ESIAB, Technopôle Brest-Iroise, 29280 Plouzané, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Le Lay
authors.affiliation: Université de Brest, EA 3882, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, ESIAB, Technopôle Brest-Iroise, 29280 Plouzané, France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Coton
authors.affiliation: Université de Brest, EA 3882, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, ESIAB, Technopôle Brest-Iroise, 29280 Plouzané, France.
authors.forename: Gwenaëlle
authors.initials: G
authors.lastname: Le Blay
authors.affiliation: Institut National de la Recherche Agronomique, UR 1268 Biopolymères Interactions Assemblages, équipe Fonctions et Interactions des Protéines, B.P. 71627, 44316 Nantes Cedex 3, France.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Chobert
authors.affiliation: Institut National de la Recherche Agronomique, UR 1268 Biopolymères Interactions Assemblages, équipe Fonctions et Interactions des Protéines, B.P. 71627, 44316 Nantes Cedex 3, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Haertlé
authors.affiliation: Institut National de la Recherche Agronomique, UR 1268 Biopolymères Interactions Assemblages, équipe Fonctions et Interactions des Protéines, B.P. 71627, 44316 Nantes Cedex 3, France.
authors.forename: Yvan
authors.initials: Y
authors.lastname: Choiset
authors.affiliation: Université de Brest, EA 3882, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, ESIAB, Technopôle Brest-Iroise, 29280 Plouzané, France.
authors.forename: Nicolas Nguyen
authors.initials: NN
authors.lastname: Van Long
authors.affiliation: Université de Brest, EA 3882, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, ESIAB, Technopôle Brest-Iroise, 29280 Plouzané, France.
authors.forename: Laurence
authors.initials: L
authors.lastname: Meslet-Cladière
authors.affiliation: Université de Brest, EA 3882, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, ESIAB, Technopôle Brest-Iroise, 29280 Plouzané, France. Electronic address: jerome.mounier@univ-brest.fr.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Mounier
mesh_terms: D019342:Acetic Acid / Q000378:metabolism; D000935:Antifungal Agents / Q000378:metabolism*; D001234:Aspergillus niger / Q000254:growth & development*; D002208:Caproates / Q000378:metabolism; D003998:Dicarboxylic Acids / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism; D055325:Eurotium / Q000254:growth & development; D006861:Hydrogen Peroxide / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000378:metabolism; D007777:Lactobacillaceae / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D010407:Penicillium / Q000254:growth & development*; D011422:Propionates / Q000378:metabolism; D011424:Propionibacterium / Q000378:metabolism*; D013172:Spores, Fungal / Q000254:growth & development*
chemical_list: D000935:Antifungal Agents; D002208:Caproates; D003998:Dicarboxylic Acids; D011422:Propionates; C037652:hexanoic acid; D019344:Lactic Acid; D000431:Ethanol; D006861:Hydrogen Peroxide; C010038:azelaic acid; D019342:Acetic Acid
keywords: Antifungal; Germination; Growth; Lactic acid bacteria; Moulds