Molecular analysis and cloning of a cellulase gene from Bacillus velezensis RB.IBE29

Bacillus velezensis RB.IBE29 was originally isolated from the rhizospheric soil of black pepper cultivated in the Central Highlands. Previous studies showed that this bacterium was a good chitinase producer, biocontrol agent, and biofertilizer. The complete genome sequence of strain RB.IBE29 was reported and revealed that it harbors the gene coding for the family 5 cellulase of glycoside hydrolases, however, this gene has not been experimentally characterized. This small work aimed to analyze and clone the gene encoding the family 5 cellulase of strain RB.IBE29 for subsequent studies. Results showed that strain RB.IBE29 possesses the celA encoding the family 5 cellulase. The ORF of the celA contains 1500 bp and encodes cellulase with 499 aa and 55.0 kDa. Primary structure analysis found that the enzyme contains a signal peptide sequence at the N-terminus, a GH5 catalytic domain, and a CBM3 domain at C-terminus. A fragment (1410 bp) without signal peptide sequence was successfully amplified and cloned in Escherichia coli DH5α. Sequencing analysis confirmed that no mutations or frameshift mutations were found in the insert of the recombinant vector from the positive clone. This work provided valuable material for our next expression, purification, and characterization of the cellulase from strain RB.IBE29.