The effect of yellow affinity substance on cellulases of Ruminococcus flavefaciens

Cellulolytic cultures of Ruminococcus flavefaciens produced a yellow affinity substance (YAS) with a strong affinity to microcrystalline cellulose (MC). YAS was bound to MC in the range of pH from 5 to 8 and at temperatures from 10 degrees C to 60 degrees C. The positive effect of YAS on adsorption of ruminococcal cellulases was demonstrated by comparing the adsorption behaviour of endoglucanases and cellobiohydrolases onto MC and YAS-treated MC. HPLC chromatography proved the presence of two yellow compounds with affinity to cellulose as well as to ruminococcal cellulases. Both YAS compounds were sensitive to oxidation. The observed YAS properties showed a close relation to YS of Clostridium thermocellum.