Carboxymethyl cellulase production optimization from newly isolated thermophilic Bacillus subtilis K-18 for saccharification using response surface methodology

Muhammad Irfan, Qudsia Mushtaq, Fouzia Tabssum, Hafiz Abdullah Shakir, Javed Iqbal Qazi

In this study, a novel thermophilic strain was isolated from soil and used for cellulase production in submerged fermentation using potato peel as sole carbon source. The bacterium was identified by 16S rRNA gene sequencing technology. Central composite design was applied for enhanced production using substrate concentration, inoculum size, yeast extract and pH as dependent variables. Highest enzyme titer of 3.50 ± 0.11 IU/ml was obtained at 2% substrate concentration, 2% inoculum size, 1% yeast extract, pH 5.0, incubation temperature of 50 °C for 24 h of fermentation period. The crude enzyme was characterized having optimum pH and temperature of 7.0 and 50 °C, respectively. The efficiency of enzyme was checked by enzymatic hydrolysis of acid/alkali treated pine needles which revealed that 54.389% saccharification was observed in acid treated pine needles. These results indicated that the cellulase produced by the Bacillus subtilis K-18 (KX881940) could be effectively used for industrial processes particularly for bioethanol production.