Formate Production by Streptococcus thermophilus Cultures

Metabolic engineering of acetaldehyde production by Streptococcus thermophilus.

The process of acetaldehyde formation by the yogurt bacterium Streptococcus thermophilus is described in this paper. Attention was focused on one specific reaction for acetaldehyde formation catalyzed by serine hydroxymethyltransferase (SHMT), encoded by the glyA gene. In S. thermophilus, SHMT also possesses threonine aldolase (TA) activity, the interconversion of threonine into glycine and ace...

Enhanced exopolysaccharide production by metabolic engineering of Streptococcus thermophilus.

It is possible that the low levels of production of exopolysaccharides (EPSs) by lactic acid bacteria could be improved by altering the levels of enzymes in the central metabolism that influence the production of precursor nucleotide sugars. To test this hypothesis, we identified and cloned the galU gene, which codes for UDP glucose pyrophosphorylase (GalU) in Streptococcus thermophilus LY03. H...

Streptococcus thermophilus.

Streptocus tmophilus, as a species designation (Orla-Jensen, 1919), has included those members of the nonhemolytic streptococci that possess the unusual combination of characteristics of extreme salt sensitivity, nonobligate thermophily, a rigorous fermentative pattern with respect to certain sugars (Sherman, 1937), and, based upon attempts to culture on synthetic media, a notoriety for nutriti...

The Fermentation of Disaccharides by Streptococcus thermophilus.

Production of beta-galactosidase from Streptococcus thermophilus grown in whey.

beta-D-Galactosidase (EC 3.2.1.23) was extracted from Streptococcus thermophilus grown in deproteinized cheese whey. Cultural conditions optimum for maximum enzyme production were pH 7.0, 40 degrees C, and 24 h. Proteose peptone (2.0%, wt/vol) and corn steep liquor (2.8%, wt/vol) were highly stimulatory, increasing the enzyme units available in their absence from 660 U/liter of medium to 18,200...