Production and characterization of endoglucanase from an indigenous yeast strain

Cellulases, group of industrially important enzymes, are commercially obtained from mold or bacterial strains. Yeasts strains have scarcely been reported for their cellulolytic potential and are not applied on industrial scale. This study was aimed at the isolation of a promising cellulolytic yeast strain with the possible biotechnological application. The strain, MK-157, was identified as Saccharomyces cerevisiae on traditional and molecular basis. The gene encoding 1,3-endoglucanase was also amplified by Nested PCR and sequenced. The activity of endoglucanase (EG) band corresponding to 30 kDa was observed in zymogram. The data showed that at 30oC and pH 7.0, in presence of 1% Carboxymethyl cellulose (CMC), the strain produced more than 15 IU/ml of EG. The activity of EG was also characterized in crude preparation. The strain was able to tolerate up to 12% alcohol and produced 5.45 % ethanol when cultivated in a complex medium. The potential of the strain to grow and produce EG on untreated and alkali-treated wheat-bran (WB) and sugarcane-bagasse (SCB) was also evaluated. The results showed the ability of the strain MK-157 to produce EG in presence of CMC, SCB and WB. The study provides some insights on less explored cellulolytic yeasts. The strain MK-157 can find its application in consolidated bioprocessing of cellulosic mass. (author)