Abstract
Mutanases are enzymes that have the ability to cleave α-1,3 linkages in glucan polymer. In the present investigation, mutanase enzyme purified from the culture filtrate of Paracoccus mutanolyticus was evaluated for Streptococcal biofilm degradation and antimicrobial activity against pathogenic fungi along with enzyme kinetics, activation energies, pH and thermal stability. Biochemical and molecular characterization depicted that the enzyme showed optimum activity at pH 5.5 and at 50 °C. It displayed Michaelis-Menten behaviour with a K(m) of 1.263 ± 0.03 (mg/ml), V(max) of 2.712 ± 0.15 U/mg protein. Thermal stability studies denoted that it required 55.46 and 135.43 kJ mol(-1) of energy for activation and deactivation in the temperature range of 30-50 °C and 50-70 °C respectively. Mutanase activity was enhanced ~ 50 and 75% by Fe(2+) and EDTA, respectively, while presence of Hg(2+) and Mn(2+) inhibit > 90% of its activity. This enzyme has a molecular mass of 138 kDa and showed monomeric nature by Zymography. Scanning electron microscopy analysis of mutanase treated Streptococcal cells revealed cleavage of linkages among the cells and complete separation of cells, indicating its potential in dentistry as an anticaries agent in the prophylaxis and therapy of dental caries. In addition, antifungal activity of mutanase against Colletotrichum capsici MTCC 10147 and Cladosporium cladosporioide MTCC 7371 revealed that the enzyme has potential towards biological control of phytopathogens which could be used as an alternative bio-control agent against chemical pesticides in the future.