title: Bacteria and yeast microbiota in milk kefir grains from different Italian regions.
abstract: Kefir grains are a unique symbiotic association of different microrganisms, mainly lactic acid bacteria, yeasts and occasionally acetic acid bacteria, cohabiting in a natural polysaccharide and a protein matrix. The microbial composition of kefir grains can be considered as extremely variable since it is strongly influenced by the geographical origin of the grains and by the sub-culturing method used. The aim of this study was to elucidate the bacteria and yeast species occurring in milk kefir grains collected in some Italian regions by combining the results of scanning electron microscopy analysis, viable counts on selective culture media, PCR-DGGE and pyrosequencing. The main bacterial species found was Lactobacillus kefiranofaciens while Dekkera anomala was the predominant yeast. The presence of sub-dominant species ascribed to Streptococcus thermophilus, Lactococcus lactis and Acetobacter genera was also highlighted. In addition, Lc. lactis, Enterococcus sp., Bacillus sp., Acetobacter fabarum, Acetobacter lovaniensis and Acetobacter orientalis were identified as part of the cultivable community. This work further confirms both the importance of combining culture-independent and culture-dependent approaches to study microbial diversity in food and how the combination of multiple 16S rRNA gene targets strengthens taxonomic identification using sequence-based identification approaches.
authors.affiliation: Dipartimento di Scienze Agrarie, Alimentari ed Ambientali, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy.
authors.forename: Cristiana
authors.initials: C
authors.lastname: Garofalo
authors.affiliation: Dipartimento di Scienze Agrarie, Alimentari ed Ambientali, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy. Electronic address: a.osimani@univpm.it.
authors.forename: Andrea
authors.initials: A
authors.lastname: Osimani
authors.affiliation: Dipartimento di Scienze Agrarie, Alimentari ed Ambientali, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy.
authors.forename: Vesna
authors.initials: V
authors.lastname: Milanović
authors.affiliation: Dipartimento di Scienze Agrarie, Alimentari ed Ambientali, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Aquilanti
authors.affiliation: Dipartimento di Agraria, Università degli Studi di Napoli Federico II, Via Università 100, 80055 Portici, Napoli, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: De Filippis
authors.affiliation: Dipartimento di Agraria, Università degli Studi di Napoli Federico II, Via Università 100, 80055 Portici, Napoli, Italy.
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Stellato
authors.affiliation: Dipartimento di Scienze Agrarie, Alimentari e Ambientali & Industrial Yeasts Collection DBVPG, Università degli Studi di Perugia, Borgo XX Giugno, 06121 Perugia, Italy.
authors.forename: Simone
authors.initials: S
authors.lastname: Di Mauro
authors.affiliation: Dipartimento di Scienze Agrarie, Alimentari e Ambientali & Industrial Yeasts Collection DBVPG, Università degli Studi di Perugia, Borgo XX Giugno, 06121 Perugia, Italy.
authors.forename: Benedetta
authors.initials: B
authors.lastname: Turchetti
authors.affiliation: Dipartimento di Scienze Agrarie, Alimentari e Ambientali & Industrial Yeasts Collection DBVPG, Università degli Studi di Perugia, Borgo XX Giugno, 06121 Perugia, Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Buzzini
authors.affiliation: Dipartimento di Agraria, Università degli Studi di Napoli Federico II, Via Università 100, 80055 Portici, Napoli, Italy.
authors.forename: Danilo
authors.initials: D
authors.lastname: Ercolini
authors.affiliation: Dipartimento di Scienze Agrarie, Alimentari ed Ambientali, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Clementi
mesh_terms: D000818:Animals; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D043302:Cultured Milk Products / Q000737:chemistry / Q000382:microbiology*; D007558:Italy; D064307:Microbiota; D010802:Phylogeny; D015003:Yeasts / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*
keywords: Acetic acid bacteria; Lactic acid bacteria; Microbial diversity; PCR-DGGE; Pyrosequencing; SEM analysis; Yeasts