Folate Production Case Study

A number of physical and nutritional growth factors have been reported to affect the folate production by microorganisms (Lin and Young, 2000; Sybesma et al., 2003). Published efforts to optimize folate production in LAB have included studies evaluating the effects of environmental conditions as temperature, pH, oxygen tension, and incubation time and composition of the medium (C and N sources, growth factors. Several investigators find higher folate production by LAB strains under conditions optimal for growth for instance with respect to temperature, pH, oxygen tension, lactose and folate precursors.

The report by Lin and Young (2000) highlights the influence of lactose, calcium chloride and incubation time on folate production in reconstituted non-fat dry milk. Lactose, in addition to playing a significant role in fermentation, also plays an important role in folate production. The increase in folate content by yoghurt culture was not significant (3-7%) when incubated for 6h with 2% lactose, but increased to 12-198% when grown for 18h. The addition of CaCl2 at 0.02% concentration decreased folate production by yoghurt culture in contrary to the result by Reif et al. (1975) who observed increased folate levels

In L. lactis addition of growth inhibitory concentrations of chloramphenicol (2 g ml-1) and erythromycin (0.1 g ml-1) lead to 40 and 215% increase in folate production, respectively. Folate production increased both in L. lactis and S. thermophilus by addition of NaCl to the growth medium. The reason for increased folate production when growth was inhibited is not clear but it could be that under conditions of low growth rate, GTP, one of folate precursors, accumulates because of decreased DNA and RNA synthesis. Thus increase in in situ folate level could be best performed at low growth rates and a high