Partial characterisation of acid-stable cellulase enzymes produced by Bacillus isolates

In this study, two acidophilic Bacillus sp. isolates exhibiting cellulase activity were obtained from soil. The isolates were designated as Bacillus sp. CNK1 and CNK2, respectively. CNK1 cellulase reached its maximum activity level at the 48th hour of the bacterium's growth period, while CNK2 cellulase reached its maximum activity at the 72nd hour. Both CNK1 and CNK2 cellulases exhibited optimal activity at 40 °C, with CNK1 cellulase showing optimal activity at pH 4.0 and CNK2 cellulase at pH 5.0. CNK1 cellulase was stimulated by CaCl2 and inhibited by MgCl2, CoCl2, EDTA, and SDS. Conversely, CNK2 cellulase was stimulated by CaCl2, CoCl2, MgCl2, and EDTA, but inhibited by SDS. Zymogram analysis determined the molecular weights of CNK1 and CNK2 cellulase enzymes to be approximately 21.1 and 231.9 kDa, respectively.