Continuous fermentation of a supplemented milk with immobilized Bifidobacterium infantis

Abstract

Bifidobacterium infantis immobilized in κ-carrageenan - locust bean gum gel beads (1.0–2.0 mm diameter) was used to ferment. 10% reconstituted skim milk supplemented with 1% yeast extract in a continuous stirred tank reactor. Cell release rate from the gel beads into the milk and growth of free cells in the bioreactor allowed for a steady inoculation of the feed, with cell counts in the outflow varying from 1.0 to 2.2 × 109 CFU/mL for dilution rates in the range 0,5 to 1,0 h-1. High mechanical stability of the gel beads was observed in milk.