Upgrading the enzymatic hydrolysis of lignocellulosic biomass by immobilization of metagenome-derived novel halotolerant cellulase on the carboxymethyl cellulose-based hydrogel

Degradation of various types of lignocellulosic biomass that require harsh pretreatment and abnormal operating conditions often occur in presence of a large amount of salt. Therefore, identification and use of stable and halotolerant cellulases is essential for industrial lignocellulose applications under extreme pH and temperature. This study focuses on discovering a novel thermostable and halotolerant cellulase from rumen microbiota by employing a multi-stage in-silico screening pipeline. According to this cost-effective strategy, the new PersiCel3 was cloned, expressed, purified, and characterized. The enzyme demonstrated suitable thermal and storage stability. To improve the thermal stability and halotolerance of the enzyme, it was immobilized on the CMC-based hydrogel. The maximum activity of the PersiCel3 could be seen in the concentration of 3 M NaCl for both free (132.46%) and immobilized (197.47%) enzyme. Applying both the free and immobilized PersiCel3 on degrading the rice straw in saline condition leads to an increment in generating the reducing sugars. The immobilized enzyme presented a significant enhancement in the hydrolysis of rice straw in saline conditions compared to its free form. Our results demonstrated the potential of the robust PersiCel3 in the harsh condition and the superb performance of the immobilized enzyme for the lignocellulosic biomass industries to increase the yield of value-added products in high temperatures and saline conditions. Graphic abstract