title: Molecular identification and physiological characterization of yeasts, lactic acid bacteria and acetic acid bacteria isolated from heap and box cocoa bean fermentations in West Africa.
abstract: Yeast, lactic acid bacteria (LAB) and acetic acid bacteria (AAB) populations, isolated from cocoa bean heap and box fermentations in West Africa, have been investigated. The fermentation dynamicswere determined by viable counts, and 106 yeasts, 105 LAB and 82 AAB isolateswere identified by means of rep-PCR grouping and sequencing of the rRNA genes. During the box fermentations, the most abundant species were Saccharomyces cerevisiae, Candida ethanolica, Lactobacillus fermentum, Lactobacillus plantarum, Acetobacter pasteurianus and Acetobacter syzygii, while S. cerevisiae, Schizosaccharomyces pombe, Hanseniaspora guilliermondii, Pichia manshurica, C. ethanolica, Hanseniaspora uvarum, Lb. fermentum, Lb. plantarum, A. pasteurianus and Acetobacter lovaniensis were identified in the heap fermentations. Furthermore, the most abundant species were molecularly characterized by analyzing the rep-PCR profiles. Strains grouped according to the type of fermentations and their progression during the transformation process were also highlighted. The yeast, LAB and AAB isolates were physiologically characterized to determine their ability to grow at different temperatures, as well as at different pH, and ethanol concentrations, tolerance to osmotic stress, and lactic acid and acetic acid inhibition. Temperatures of 45 °C, a pH of 2.5 to 3.5, 12% (v/v) ethanol and high concentrations of lactic and acetic acid have a significant influence on the growth of yeasts, LAB and AAB. Finally, the yeastswere screened for enzymatic activity, and the S. cerevisiae, H. guilliermondii, H. uvarumand C. ethanolica species were shown to possess several enzymes that may impact the quality of the final product.
authors.affiliation: University of Torino, Department of Agriculture, Forest and Food Sciences, Largo Paolo Braccini 2, 10095 Grugliasco, Torino, Italy.
authors.forename: Simonetta
authors.initials: S
authors.lastname: Visintin
authors.affiliation: University of Torino, Department of Agriculture, Forest and Food Sciences, Largo Paolo Braccini 2, 10095 Grugliasco, Torino, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Alessandria
authors.affiliation: SOREMARTEC ITALIA S.r.l., Piazza Ferrero 1 - 12051 Alba, Cuneo, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Valente
authors.affiliation: University of Torino, Department of Agriculture, Forest and Food Sciences, Largo Paolo Braccini 2, 10095 Grugliasco, Torino, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Dolci
authors.affiliation: University of Torino, Department of Agriculture, Forest and Food Sciences, Largo Paolo Braccini 2, 10095 Grugliasco, Torino, Italy. Electronic address: lucasimone.cocolin@unito.it.
authors.forename: Luca
authors.initials: L
authors.lastname: Cocolin
mesh_terms: D019342:Acetic Acid / Q000378:metabolism; D000091:Acetobacter / Q000302:isolation & purification; D000354:Africa, Western; D044822:Biodiversity; D002099:Cacao / Q000378:metabolism / Q000382:microbiology*; D000431:Ethanol; D005285:Fermentation / Q000502:physiology*; D055321:Hanseniaspora / Q000302:isolation & purification / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D052197:Limosilactobacillus fermentum / Q000302:isolation & purification; D048191:Lactiplantibacillus plantarum / Q000302:isolation & purification; D012335:RNA, Ribosomal / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism; D015003:Yeasts / Q000201:enzymology / Q000302:isolation & purification* / Q000378:metabolism*
chemical_list: D012335:RNA, Ribosomal; D012336:RNA, Ribosomal, 16S; C065039:RNA, ribosomal, 25S; D019344:Lactic Acid; D000431:Ethanol; D019342:Acetic Acid
keywords: Box fermentation; Cocoa beans; Heap fermentation; Microbial dynamics; Physiological characterization; Rep-PCR