Electrostatic generation of alginate microbeads loaded with brewing yeast

The substantial concern with the possible use of immobilized yeast cells fo r beer production is reduction of internal mass transfer resistance during continuous fermentation. One way to minimise this problem is to use small-d iameter beads. The effects of bead diameters in the range 0.3-2.0 mm on yea st cell immobilization and growth over a short-term cultivation were invest igated. Bead diameters in the range 0.5-0.6 mm were optimal and provided ra pid cell growth and the highest final cell concentration (2.33 x 10(9) cell s/ml of beads). Electrostatic droplet generation was investigated as a tech nique for production of alginate microbeads. The effects of applied potenti al, internal needle diameter and electrode position on bead diameter were a ssessed. The results have shown that this method can be used for controlled production of small-size microbeads loaded with yeast. Depending on applie d conditions it was possible to produce the beads in the range 250 mum-2.0 mm in diameter. (C) 2001 Elsevier Science Ltd. All rights reserved.