Effectiveness of cross-linked enzyme aggregates of cellulolytic enzymes in hydrolyzing wheat straw.

Development of industrially potent cellulolytic enzymes is one of the greatest challenges faced in lignocellulosic feed-stock based bio-refining. In the current work cross-linked enzyme aggregates (CLEAs) of commercial cellulase mix were successfully prepared and their performance to be used as potential industrial enzymes in terms of stability and wheat straw hydrolysis was evaluated. The CLEAs were more stable compared to native enzymes with half-lives being 2.30-, 1.56-, 3.07- and 1.67-fold higher at 70°C for filter paper activity (FPA), endoglucanase, β-glucosidase and xylanase, respectively. CLEAs retained 77.4% of endoglucanase and 85.9% of xylanase activity after five cycles of hydrolysis of soluble substrates such as carboxymethyl cellulose and xylan, respectively. A maximum saccharification yield of 31.8% by soluble enzymes and 32.9% by CLEAs were obtained when alkali-pretreated wheat straw was subjected to hydrolysis. On repeated batch hydrolysis for five consecutive cycles of 24 h each, the CLEAs showed an overall higher saccharification yield of 43.3% compared to 31.8% with soluble enzymes.