Novel precipitated fluorescent substrates for the screening of cellulolytic microorganisms

Abstract

New substrates, 2-(2′-benzothiazolyl)-phenyl ( BTP) cellooligosaccharides with degree of polymerization (d.p.) 2–4 ( BTPG 2–4) were synthesized for the screening of microbial cellulolytic activity in plate assays. The substrates were very efficient that was shown for several cellulolytic bacteria, including yeast-like isolates from Kamchatka hot springs. Three tested bacterial strains and eighteen of 30 of the yeast isolates showed ability to degrade cellulose with cellobiohydrolase, β-glucosidase and endo-cellulase activities measured with standard substrates. The structures of 2-(2′-benzothiazolyl)-phenyl oligosaccharides were solved by NMR- and mass-spectrometry. The usefulness of the 2-(2′-benzothiazolyl)-phenyl substrates were also shown during purification of the B. polymyxa cellulolytic complex, which consists of at least three types of the enzymes: cellobiohydrolase, endo-β- d-glucanase and β-glucosidase.