Lactobacillus delbrueckii ssp. bulgaricus (CCR.C14009) and L. acidophilus (CCRC14079), immobilized with chitosan and polyacrylamide, were tested for CLA production. A 10-ml aliquot of L. delbrueckii ssp. bulgaricus cell suspension (3.59 x 10(7) CFU/ ml) was adsorbed to 0.5 g chitosan and polyacrylamide, mixed with 0.2 ml linoleic acid (0.9 g/ml), and incubated at 37 degrees C for 24 h at pH 5, 6, 7, and 8 for CLA production. CLA levels, produced by immobilized cells of L. delbrueckii ssp. bulgaricus and L. acidophilus with increasing cell counts to 1.08 and 1.28 x 10(10) CFU/ml, respectively, at optimal reaction pHs were evaluated. More CLA was formed at pH 8 of chitosan and pH 7 of polyacrylamide-immobilized L. delbrueckii ssp. bulgaricus cell treatments. Increase in cell count resulted in higher CLA production. The adsorption of L. delbrueckii ssp. bulgaricus cells onto polyacrylamide at pH 7 showed significant improvement in total CLA level. Results demonstrated a potential for enhancing CLA production through immobilization. (c) 2004 Elsevier Ltd. All rights reserved.
