Identification and Enzyme Activity Comparison of Cellulase-producing Bacillus

Objective The research was carried out to screen out celllulase-producing strains from 14 strains of bacteria in order to provide a material basis for the development of new feed additives.

Method The cellulase-producing strains were screened out from 14 strains by Congo red staining. Then the colony morphologies of them were observed and 16S rDNA gene sequence homology was analyzed and identified. After comparing the ability of each strain to degrade cellulose by Congo red staining, the cellulase activity of each strain was detected by DNS method.

Result Seven cellulase-producing strains were screened, including 4 strains of Bacillus licheniformis and 3 strains of Bacillus subtilis. Based on Congo red staining, it was preliminarily identified that the cellulose degradation ability of 7 Bacillus strains was showed as: LW006 > LW 005 > LW004 > LW002 > LW007 > LW003 > LW001. Among them, strain LW006 (B. subtilis) had the strongest ability to degrade cellulose, producing a clear circle with a diameter of 22.5 mm. The cellulase activities of 7 strains of Bacillus were determined by DNS method as follows: LW006 > LW005 > LW004 > LW007 > LW003 > LW002 > LW001. Among them, strain LW006 (B. subtilis) showed the highest cellulase activity with 1.22(±0.07) U/mL (P < 0.01).

Conclusion Strain LW006 is a relatively high cellulase-producing strain, which is expected to provide new strain resources for new feed additives.