Production of extracellular β-mannanases by yeasts and yeast-like microorganisms

Publisher Website
Google Scholar
Abstract
A new screening method for simultaneous detection of endo-β-1,4-mannanase and endo-β-1,4-xylanase producing microorganisms is described. Two differently dyed substrate Ostazin Brilliant Red-galactomannan and Remazol Brilliant Blue-xylan were incorporated into the same agar media. Decolorizing of one or both substrates around the cell colonies indicates secretion of the corresponding enzyme(s). The method was used to screen 449 yeasts and yeast-like microorganisms belonging to 68 different genera. The secretion of endo-β-1,4-mannanases and/or endo-β-1,4-xylanases was found within 10 genera (42 positive strains out of 261 tested). A low frequency of occurrence of endo-β-1,4-mannanases was observed within the generaCryptococcus (1 positive strain out of 15 tested),Geotrichum (1 of 6) andPichia (1 of 35). The highest frequency of occurrence of endo-β-1,4-mannanases was found within the generaStephanoascus (2 of 2) andAureobasidium (14 of 14). Strains hydrolyzing Ostazin Brilliant Red-galactomannan were cultivated in liquid media containing 1 % locust bean gum. The best producers of extracellular endo-β-1,4-mannanases were found to be the strains ofAureobasidium pullulans.