Quantification of yeast flocculation

Abstract

A sedimentation method based in the Helm's flocculation test was improved. In this method, all steps were standardised: initial cell concentration, agitation, sampling and determination of settled cells. The results obtained with the sedimentation test do not differ significantly (P=0.05) from those obtained with the Stratford test; besides the precision of the two methods do not differ significantly (P=0.05). The results presented clearly demonstrated that the method improved in this work is rigorous for quantification of yeast flocculation and allows the differentiation of flocculation ability of the strains. The respective micro-flocculation tests were also compared; Stratford micro-flocculation test was selected as producing the most meaningful results.