Service Communautaire d'Information sur la Recherche et le Développement - CORDIS

Optimisation of fermentation technology for CLA production in milk based medium

For use in product manufacture and spray drying, CLA-producing bifidobacteria should grow and produce CLA efficiently in milk based medium (RSM). CLA production was assessed in RSM, and found in general to be inefficient. The increased conversion of linoleic acid to CLA was assessed following addition of a selection of bifidogenic supplements to 20 % RSM.

This was done by assessing the % conversion of linoleic acid to CLA in RSM containing a selection of supplements, including sugars, short chain fatty acids, and other bifidogenic agents. Of the supplements tested, sodium propionate and yeast extract were found to be the most effective, resulting in conversion rates from linoleic acid to c9, t11 CLA of >50% in RSM, while casein hydrolysate and sodium acetate also yielded satisfactory results, yielding conversion rates of 40-50%.

A medium containing 200mM sodium acetate and 20mg mL-1 yeast extract was selected for further evaluation, and fermentation of B. breve NCIMB 702258 in this medium increased the percentage bioconversion of 0.35 mg ml-1 linoleic acid to the c9, t11 CLA isomer, from 15.5 +/- 1.1% (in 20% RSM) to 48.1 +/- 2.2 %. Inclusion of a further supplement into this medium, i.e. inulin (20mg mL-1), and optimization of inoculum and linoleic acid concentration resulted in further increases in the conversion rate up to 55.0 +/- 3.2%. This rate of conversion of linoleic acid to CLA was found to be comparable to that obtained in synthetic medium (cys-MRS), in which 58.8 +/- 2.7% of the linoleic acid was converted to c9, t11 CLA, under identical experimental conditions.

Reported by

Moorepark Food Research Centre, Fermoy,