Studies On The Culture Of Lactic Acid Bacteria Immobilized By NaCS-PDMDAAC Biomicrocapsule

The NaCS-PDMDAAC microcapsule was used to immobilize the lactic acid bacteria, and the effect of species, temperature, pH, etc was studied. The species had deep effect on the producing of lactic acid. At 40 癈 and pH 6.0, the Lactobacillus brevis can grow well and produce the most amount of lactic acid. The effect of the concentration of glucose and lactic acid on immobilized Lactobacillus can be neglected.Free bacteria culture had some advantages in comparison with immobilized bacteria culture. The less mass transfer resist, more production rate and simpler of separation process would make the microcapsule a broader applications. The diffusion properties of the microcapsule are studied and the diffusion coefficients were measured. The effective diffusion coefficients of lactic acid and glucose are 10.56xlO~lom2-s~' and 3.75xlO"10m2-s"'. The effective diffusion coefficients of entrapped growing lactic acid bacteria of lactic acid and glucose are 9.89xlO~'癿2-s~' and 3.62xlO~'癿2-s~1. respectively. Partition coefficients also confirmed the obstruction effect due to the cells, and decreased from 0.876 to 0.814. from 0.952 to 0.913, for lactic acid and glucose, respectively. A mathematical model was propose to analyze the mass transfer behavior in lactic acid fermentation using immobilized cells in microcapsule. The application of this model can be used in other cells immobilized by NaCS-PDMDAAC microcapsule.