2.3. Identification and examination of growth characteristics of isolated cellulolytic bacterium
The isolated strain was morphologically identified by Gram staining and malachite green spore staining [13], and physiological-biochemical identification was performed in accordance with Bergey's Manual of Systematic Bacteriology [14]. For further identification, 16S rRNA was amplified by polymerase chain reaction (PCR) from the genomic DNA of the strain using universal primer pair 27F/1492R [15]. The purified PCR products were cloned into the pGEM-T vector and sequenced by BGI Biotechnology. The sequencing results were compared using the Basic Local Alignment Search Tool (BLAST) program on NCBI and 16S rRNA gene sequence homology analysis using GenBank data. A phylogenetic tree was constructed using the neighbor-joining model of the MEGA 5.1 program. Lastly, the microbial optical density (OD) at 600 nm was determined at different growth periods to reflect the growth characteristics of the bacterium.