Kumar, Krishan2020-08-242023-10-192020-08-242023-10-192019ROLL NO.146106035https://gyan.iitg.ac.in/handle/123456789/1607Supervisor: Arun GoyalThe thermophilic bacterium Clostridium thermocellum contains multienzyme complex called cellulosome which is known to degrade recalcitrant substrates. In this study one of the cellulosomal enzymes, β-1,3-glucanase (CtLam81A) of family 81 GH from Clostridium thermocellum was explored. CtLam81A was highly thermostable and displayed endo β-1,3-glucanase activity. The in silico and X-ray crystal structure of CtLam81A showed N-terminal β-sandwich domain, a (α/α)6 domain and a short β-sandwich domain at C-terminal. Structural analysis of CtLam81A displayed the inverting hydrolytic mechanism. The docking of laminari-oligosaccharides to CtLam81A revealed that the active site can occupy maximum 5 glucose residues of β-1,3-glucan. The aromatic amino acid residues create the binding pocket at active site of CtLam81A to hold the ligand. The laminari-oligosaccharides generated by hydrolysis of curdlan by CtLam81A displayed prebiotic properties. They showed resistance or low digestibility against artificial gastric juice, intestinal fluid and α-amylase than inulin indicating their bioavailability to the probiotic bacteria present in the gastrointestinal tract of human. Therefore, laminari-oligosaccharides can be used for functional food additives.enBIOSCIENCES AND BIOENGINEERINGThesis