Among the various nitrogen sources, casein hydrolysate (CH) showed the highest cell growth and EPS
production for both strains after 18 h incubation and therefore it was selected for subsequent work. Based
on fermentation experiments using different levels of CH (from 0.5 to 2.5% w/v) it was deduced that 1.5%
(w/v) CH resulted in the highest EPS production, yielding 102 and 285 mg L−1 for B. infantis NCIMB
702205 and B. longum subsp. infantis CCUG 52486, respectively.