Abstract: The present invention provides a method for manufacturing organic acid by high-efficiency fermentation, which comprises the steps of continuous culture of organic acid bacteria and collection of organic acid produced from the culture employing a cell-recycle multiple-stage continuous fermentor with serially connected fermentors, each of which comprises a fermentor containing a ferment container, temperature controller, stirrer, and pH controller; pumps for efflux-circulation of media from the fermentor; and, cell separator for separation and circulation of media from the pumps. According to the present method, the high-concentration lactic acid of 90 g/L can be produced with the high productivity of 50 g/L/h, which can reduce the facility cost and production cost in the bulk manufacturing process.

Abstract: A method is provided for immobilization of whole microbial cells containing enzymes in Ca-alginate capsules. Whole microbial cells are mixed with a CaCl.sub.2 solution, a small amount of xanthan gum is added, the resultant mixture is added drop-wise while stirring to a Na-alginate solution containing a small amount of surfactant which is preferably polyoxyethylenesorbitan monolaurate to obtain the capsules containing the cells. The capsules may be washed with distilled water, hardened by in a CaCl.sub.2 solution and incubated in a growth medium. The microbial cells are bacteria or fungi cells and may be recombinant cells.