A novel bacterial strain, MG7, with high cellulase activity was isolated and identified by morphological characteristics and molecular phylogeny analysis as Paenibacillus barcinonensis. Maximum production of cellulase by MG7 was observed at pH 7.0 and $35^{circ}C$. The enzyme was purified with a specific activity of 16.88 U/mg, the cellulase activity was observed in a zymogram, and its molecular mass (58.6 kDa) was confirmed by SDS-PAGE. The purified enzyme showed maximum activity at pH 6.0 and $65^{circ}C$ and degraded cellulosic substrates such as carboxy methyl cellulose (CMC), Avicel, filter paper, and ${eta}$-glucan. The enzyme showed stability with 0.5% concentration of various surfactants. The $K_m$ and $V_{max}$ of cellulase for CMC and Avicel were found to be 0.459mg/ml and 10.46mg/ml/h, and 1.01 mg/ml and 10.0 mg/ml/h, respectively. The high catalytic activity and its stability to temperature, pH, surfactants, and metal ions indicated that the cellulase enzyme by MG7 is a good candidate for biotechnological applications.