Kappa-carrageenan gel immobilisation of lager brewing yeast

Abstract

Kappa-carrageenan has been found to be a suitable carrier for yeast immobilisation for continuous fermentation systems due to its unique properties. Brewing lager yeast immobilised in kappa-carrageenan beads was studied both in batch and in a continuously fermenting gas lift bioreactor. The cells were monitored over a six month period of continuous fermentation. Viability (methylene blue), immobilised cell concentration and distribution, and the morphological characteristics of the cells (electron microscopy) were investigated. Viability of cells within the beads was found to decline to less than 50% after six months of continuous wort fermentation and maximum bead population did not exceed 109 cells/mL of gel bead.