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Streptococcus thermophilus strains of plant origin as dairy starters: Isolation and characterisation
Author(s) -
Umamaheswari Thiyagamoorthy,
Anbukkarasi Kaliyaperumal,
Singh Prashant,
Tomar Sudhir K,
Singh Rameshwar
Publication year - 2014
Publication title -
international journal of dairy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.061
H-Index - 53
eISSN - 1471-0307
pISSN - 1364-727X
DOI - 10.1111/1471-0307.12098
Subject(s) - streptococcus thermophilus , biology , isolation (microbiology) , microbiology and biotechnology , diacetyl , food science , 16s ribosomal rna , bacteria , fermentation , lactobacillus , genetics
Streptococcus thermophilus strains have been isolated mainly from dairy environments. To prospect for new strains of S. thermophilus , isolation was made from different plant sources. In this study, 74 plant isolates were characterised as S. thermophilus by a polyphasic approach and by 16S rRNA sequencing. The isolates were further evaluated for their physiological and biochemical properties. Plant isolates exhibited good acid production and varying proteolytic activity. All the isolates showed acetaldehyde and capsular exopolysaccharide (EPS) production and few revealed diacetyl production. In contrast to industrial strains, six isolates were able to ferment galactose and 25 were found to have no urease activity. Both the plant isolates and reference dairy cultures were found to possess similar physiological and biochemical properties and can be considered for developing new starters.