title: Relationships between functional genes in Lactobacillus delbrueckii ssp. bulgaricus isolates and phenotypic characteristics associated with fermentation time and flavor production in yogurt elucidated using multilocus sequence typing.
abstract: Lactobacillus delbrueckii ssp. bulgaricus (L. bulgaricus) is well known for its worldwide application in yogurt production. Flavor production and acid producing are considered as the most important characteristics for starter culture screening. To our knowledge this is the first study applying functional gene sequence multilocus sequence typing technology to predict the fermentation and flavor-producing characteristics of yogurt-producing bacteria. In the present study, phenotypic characteristics of 35 L. bulgaricus strains were quantified during the fermentation of milk to yogurt and during its subsequent storage; these included fermentation time, acidification rate, pH, titratable acidity, and flavor characteristics (acetaldehyde concentration). Furthermore, multilocus sequence typing analysis of 7 functional genes associated with fermentation time, acid production, and flavor formation was done to elucidate the phylogeny and genetic evolution of the same L. bulgaricus isolates. The results showed that strains significantly differed in fermentation time, acidification rate, and acetaldehyde production. Combining functional gene sequence analysis with phenotypic characteristics demonstrated that groups of strains established using genotype data were consistent with groups identified based on their phenotypic traits. This study has established an efficient and rapid molecular genotyping method to identify strains with good fermentation traits; this has the potential to replace time-consuming conventional methods based on direct measurement of phenotypic traits.
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, P. R. China, Inner Mongolia Agricultural University, Huhhot, 010018, China; Dairy Processing Laboratory of National Dairy Production Technology and Research Centre, Huhhot, 010018, China.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Liu
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, P. R. China, Inner Mongolia Agricultural University, Huhhot, 010018, China; Dairy Processing Laboratory of National Dairy Production Technology and Research Centre, Huhhot, 010018, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Yu
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, P. R. China, Inner Mongolia Agricultural University, Huhhot, 010018, China; Dairy Processing Laboratory of National Dairy Production Technology and Research Centre, Huhhot, 010018, China.
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Sun
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, P. R. China, Inner Mongolia Agricultural University, Huhhot, 010018, China; Dairy Processing Laboratory of National Dairy Production Technology and Research Centre, Huhhot, 010018, China.
authors.forename: Yuqin
authors.initials: Y
authors.lastname: Song
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, P. R. China, Inner Mongolia Agricultural University, Huhhot, 010018, China; Dairy Processing Laboratory of National Dairy Production Technology and Research Centre, Huhhot, 010018, China.
authors.forename: Xueni
authors.initials: X
authors.lastname: Wang
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, P. R. China, Inner Mongolia Agricultural University, Huhhot, 010018, China; Dairy Processing Laboratory of National Dairy Production Technology and Research Centre, Huhhot, 010018, China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Wang
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, P. R. China, Inner Mongolia Agricultural University, Huhhot, 010018, China; Dairy Processing Laboratory of National Dairy Production Technology and Research Centre, Huhhot, 010018, China.
authors.forename: Tuoya
authors.initials: T
authors.lastname: Wuren
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, P. R. China, Inner Mongolia Agricultural University, Huhhot, 010018, China; Dairy Processing Laboratory of National Dairy Production Technology and Research Centre, Huhhot, 010018, China.
authors.forename: Musu
authors.initials: M
authors.lastname: Zha
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, P. R. China, Inner Mongolia Agricultural University, Huhhot, 010018, China; Dairy Processing Laboratory of National Dairy Production Technology and Research Centre, Huhhot, 010018, China.
authors.forename: Bilige
authors.initials: B
authors.lastname: Menghe
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, P. R. China, Inner Mongolia Agricultural University, Huhhot, 010018, China; Dairy Processing Laboratory of National Dairy Production Technology and Research Centre, Huhhot, 010018, China. Electronic address: hepingdd@vip.sina.com.
authors.forename: Zhang
authors.initials: Z
authors.lastname: Heping
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D005285:Fermentation; D048668:Lactobacillus delbrueckii / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D008892:Milk / Q000737:chemistry*; D008969:Molecular Sequence Data; D058885:Multilocus Sequence Typing; D010641:Phenotype; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics / Q000378:metabolism; D013649:Taste; D015014:Yogurt / Q000032:analysis*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S
keywords: Lactobacillus delbrueckii ssp. bulgaricus; acidification; dairy starter; functional gene; multilocus sequence typing