Screening For Gamma-Cgtase

Abstract

Cyclodextrin glucosyltransferase (CGTase)-pos. alkalophilic microorganisms were selected by parallel application of two screening techniques based on colorimetric distinction of the colonies at the cultivation plate level. One of the techniques uses Congo Red and xylene cyanole dyes which form a clear halo only in the presence of γ-cyclodextrin (γ-CD), whereas the other uses phenolphthalein that is specific for β-cyclodextrin (β-CD). The CGTase produced by strains selected up to now yields, however, mainly β-CD. The prodn. of β-CD by the CGTase of strain 37 is, nevertheless, very interesting since β-cyclodextrin concn. reached 16 mM at 50°C, pH 8.0, 10% w/v initial substrate concn. [on SciFinder(R)]