title: Bacterial community dynamics during industrial malting, with an emphasis on lactic acid bacteria.
abstract: Characterization of the microflora during malting is an essential step towards process management and optimization. Up till now, however, microbial characterization in the malting process has mostly been done using culture-dependent methods, probably leading to biased estimates of microbial diversity. The aim of this study was to characterize the bacterial communities using two culture-independent methods, including Terminal Restriction Fragment Length Polymorphism (T-RFLP) and 454 pyrosequencing, targeting the 16S rRNA gene. Studied samples originated from two harvest years and two malting houses malting the same batch of barley. Besides targeting the entire bacterial community (T-RFLP), emphasis was put on lactic acid bacteria (LAB) (T-RFLP and 454 pyrosequencing). The overall bacterial community richness was limited, but the community structure changed during the process. Zooming in on the LAB community using 454 pyrosequencing revealed a total of 47 species-level operational taxonomic units (OTUs). LAB diversity appeared relatively limited since 88% of the sequences were covered by the same five OTUs (representing members of Weissella, Lactobacillus and Leuconostoc) present in all samples investigated. Fluctuations in the relative abundances of the dominant LAB were observed with the process conditions. In addition, both the year of harvest and malting house influenced the LAB community structure.
authors.affiliation: Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (M(2)S), KU Leuven, Campus De Nayer, B-2860 Sint-Katelijne-Waver, Belgium; Scientia Terrae Research Institute, B-2860 Sint-Katelijne-Waver, Belgium; Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Belgium; Leuven Institute for Beer Research (LIBR), KU Leuven, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Justé
authors.affiliation: Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Belgium; Leuven Institute for Beer Research (LIBR), KU Leuven, Belgium; Laboratory of Enzyme, Fermentation, and Brewing Technology (EFBT), M(2)S, KU Leuven, KAHO Sint-Lieven Technology Campus, B-9000 Gent, Belgium.
authors.forename: S
authors.initials: S
authors.lastname: Malfliet
authors.affiliation: Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (M(2)S), KU Leuven, Campus De Nayer, B-2860 Sint-Katelijne-Waver, Belgium; Scientia Terrae Research Institute, B-2860 Sint-Katelijne-Waver, Belgium; Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Belgium; Leuven Institute for Beer Research (LIBR), KU Leuven, Belgium.
authors.forename: M
authors.initials: M
authors.lastname: Waud
authors.affiliation: Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (M(2)S), KU Leuven, Campus De Nayer, B-2860 Sint-Katelijne-Waver, Belgium; Scientia Terrae Research Institute, B-2860 Sint-Katelijne-Waver, Belgium; Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Belgium; Leuven Institute for Beer Research (LIBR), KU Leuven, Belgium.
authors.forename: S
authors.initials: S
authors.lastname: Crauwels
authors.affiliation: Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Belgium; Leuven Institute for Beer Research (LIBR), KU Leuven, Belgium; Laboratory of Enzyme, Fermentation, and Brewing Technology (EFBT), M(2)S, KU Leuven, KAHO Sint-Lieven Technology Campus, B-9000 Gent, Belgium.
authors.forename: L
authors.initials: L
authors.lastname: De Cooman
authors.affiliation: Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Belgium; Leuven Institute for Beer Research (LIBR), KU Leuven, Belgium; Laboratory of Enzyme, Fermentation, and Brewing Technology (EFBT), M(2)S, KU Leuven, KAHO Sint-Lieven Technology Campus, B-9000 Gent, Belgium.
authors.forename: G
authors.initials: G
authors.lastname: Aerts
authors.affiliation: Center for Microbial Ecology, Michigan State University, East Lansing, MI 48824, USA.
authors.forename: T L
authors.initials: TL
authors.lastname: Marsh
authors.affiliation: Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (M(2)S), KU Leuven, Campus De Nayer, B-2860 Sint-Katelijne-Waver, Belgium; Scientia Terrae Research Institute, B-2860 Sint-Katelijne-Waver, Belgium; Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Belgium; Leuven Institute for Beer Research (LIBR), KU Leuven, Belgium.
authors.forename: S
authors.initials: S
authors.lastname: Ruyters
authors.affiliation: Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (M(2)S), KU Leuven, Campus De Nayer, B-2860 Sint-Katelijne-Waver, Belgium; Scientia Terrae Research Institute, B-2860 Sint-Katelijne-Waver, Belgium; Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Belgium; Leuven Institute for Beer Research (LIBR), KU Leuven, Belgium.
authors.forename: K
authors.initials: K
authors.lastname: Willems
authors.affiliation: Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (M(2)S), KU Leuven, Campus De Nayer, B-2860 Sint-Katelijne-Waver, Belgium; Scientia Terrae Research Institute, B-2860 Sint-Katelijne-Waver, Belgium; Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Belgium; Leuven Institute for Beer Research (LIBR), KU Leuven, Belgium.
authors.forename: P
authors.initials: P
authors.lastname: Busschaert
authors.affiliation: Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (M(2)S), KU Leuven, Campus De Nayer, B-2860 Sint-Katelijne-Waver, Belgium; Scientia Terrae Research Institute, B-2860 Sint-Katelijne-Waver, Belgium; Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Belgium; Leuven Institute for Beer Research (LIBR), KU Leuven, Belgium. Electronic address: bart.lievens@kuleuven.be.
authors.forename: B
authors.initials: B
authors.lastname: Lievens
mesh_terms: D044822:Biodiversity; D005511:Food Handling; D001467:Hordeum / Q000737:chemistry / Q000382:microbiology*; D019344:Lactic Acid / Q000378:metabolism; D007777:Lactobacillaceae / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length
chemical_list: D019344:Lactic Acid
keywords: 454 pyrosequencing; Lactic acid bacteria (LAB); Malt microflora; Microbial community analysis; Terminal restriction fragment length polymorphism (T-RFLP)