Structural insights into the thermal stability of endo-mannanase belonging to family 26 from Bacillus sp CFR1601

Structural insights into the thermal stability of endo-mannanase belonging to family 26 from Bacillus sp. CFR1601 Praveen K. Srivastava, Appu Rao G. Appu Rao, Mukesh Kapoor: Department of Protein Chemistry and Technology, CSIR-Central Food Technological Research Institute, Cheluvamba Mansion, Mysore-570020. Endo-β-mannanase (endo-1,4-β-mannosidase; EC 3.2.1.78) is the key enzyme that catalyzes random hydrolysis of β-mannosidic linkages in mannans and heteromannans. Mannanases play an important role in modification of gums, oil drilling industry and in the preparation of pre-biotics for food industry. An endo-mannanase obtained from soil bacterium Bacillus sp. CFR1601 was purified to apparent homogeneity and characterized. Partial biochemical and molecular characterization of purified enzyme reveals that it belongs to the glycosyl hydrolase family 26 with highest specific activity (10,400 ± 100 IU/mg) in its class. The enzyme retains its structure and activity up to 700C with activation energy of 10.8 ± 1.0 kcalmol-1. Based on kinetics of thermal inactivation, enthalpy, free energy and entropy were found to be 86.7± 0.0 kcalmol-1, 24.192± 0.7 kcalmol-1 and 186.3± 0.21cal mol-1 K-1,respectively. Thermal stability measurements in presence of additives suggested the role of surface charges in thermal inactivation. Modification of surface charges could lead to development of highly stable and active endo-mannanase for food and oil drilling applications. Source of research support: Council of Scientific and Industrial Research (CSIR), New Delhi, Indi