title: Exopolysaccharide production by lactose-hydrolyzing bacteria isolated from traditionally fermented milk.
abstract: With increasing consumer demands for safer, healthier and more natural products, bacterially produced exopolysaccharides (EPSs) are becoming a viable option as an additive in designer-type foods. Fresh milk samples from cattle and sheep were collected from informal settlements in South Africa. After a three day incubation period at 25 degrees C, 550 bacterial strains were isolated and evaluated for EPS production from lactose as sole carbon source. Strains producing EPS on lactose were identified to species level with 16S rRNA gene sequencing and encompass 11 Gram-positive and 6 Gram-negative bacteria. EPS production was assigned for the first time to members of the species Staphylococcus hominis and Enterococcus lactis, and also to apparently novel species of the genera Sphingomonas and Acinetobacter. The polymers consisted mainly out of galactose and glucose, while a few isolates also incorporated rhamnose. Isolates produced diverse biopolymers as seen by significant differences in monomer ratios.
authors.affiliation: Institute for Plant Biotechnology, Genetics Department, Stellenbosch University, Matieland 7602, Stellenbosh, South Africa. rkrit@sun.ac.za
authors.forename: Rolene
authors.initials: R
authors.lastname: Bauer
authors.forename: Jan P
authors.initials: JP
authors.lastname: Bekker
authors.forename: Nathan van
authors.initials: Nv
authors.lastname: Wyk
authors.forename: Christian
authors.initials: C
authors.lastname: du Toit
authors.forename: Leon M T
authors.initials: LM
authors.lastname: Dicks
authors.forename: Jens
authors.initials: J
authors.lastname: Kossmann
mesh_terms: D000150:Acinetobacter / Q000302:isolation & purification / Q000378:metabolism; D000818:Animals; D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001483:Base Sequence; D002417:Cattle; D016983:Enterococcus / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D005285:Fermentation; D006601:Hexoses / Q000032:analysis*; D006868:Hydrolysis; D007785:Lactose / Q000378:metabolism*; D008892:Milk / Q000382:microbiology*; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis* / Q000235:genetics; D012335:RNA, Ribosomal / Q000032:analysis; D017385:Sequence Homology; D012756:Sheep; D013019:South Africa; D020578:Sphingomonas / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D041181:Staphylococcus hominis / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D006601:Hexoses; D011135:Polysaccharides, Bacterial; D012335:RNA, Ribosomal; D007785:Lactose