Screening of lactic acid bacteria isolates from dairy and cereal products for exopolysaccharide production and genes involved.
A total of 174 lactic acid bacteria (LAB) strains isolated from dairy and cereal products were screened for the production of exopolysaccharides (EPS). Therefore, a rapid screening method was developed based on ultrafiltration and gel permeation chromatography. Furthermore, a screening through the polymerase chain reaction (PCR) was performed with primer pairs targeting different genes involved in EPS production. Nine isolates produced a homopolysaccharide of the glucan type, whereas only one strain produced a heteropolysaccharide. The production of a glucan by a strain of Lactococcus lactis and the production of a heteropolysaccharide by a strain of Lactobacillus curvatus are reported for the first time. The PCR screening revealed many positive strains. For three of the ten EPS-producing strains, no corresponding genes could be detected. Furthermore, a lot of strains possessed one or more eps genes but did not produce an EPS. Therefore, a screening on the molecular level should always be accompanied by another screening method that is able to distinguish true EPS producer strains from non-producing ones. Statistical analysis did not reveal any relationship between the type and origin of the strains, the presence or absence of a capsular polysaccharide or EPS, and the presence or absence of eps genes.
Van der Meulen
Roel
R
Research Group of Industrial Microbiology and Food Biotechnology (IMDO), Department of Applied Biological Sciences and Engineering, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium.
Grosu-Tudor
Silvia
S
Mozzi
Fernanda
F
Vaningelgem
Frederik
F
Zamfir
Medana
M
de Valdez
Graciela Font
GF
De Vuyst
Luc
L
D000595:Amino Acid Sequence; D000818:Animals; D003611:Dairy Products / Q000382:microbiology*; D002523:Edible Grain / Q000382:microbiology*; D005374:Filtration; D005516:Food Microbiology; D006801:Humans; D007778:Lactobacillus / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D016133:Polymerase Chain Reaction / Q000379:methods; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis* / Q000235:genetics*; D016415:Sequence Alignment
D011135:Polysaccharides, Bacterial