Isolation, Identification and Enzyme Activity Determination of Cellulose-degrading Bacteria from the Intestinal Symbionts of Cyrtotrachelus buqueti in Guizhou

Purpose To isolate and identify symbiotic cellulose-degrading bacteria from the intestine of Cyrtotrachelus buqueti, and to evaluate their cellulase activities, providing bacterial resources for the efficient utilization of cellulose resources.

Methods A medium with sodium carboxymethyl cellulose as the sole carbon source was used to isolate and screen intestinal symbiotic cellulose-degrading bacteria from C. buqueti by combining Congo red staining. The bacteria were identified through 16S rRNA gene sequence comparison, and their endoglucanase, exoglucanase, and β-glucosidase activities were measured using the 3,5-dinitrosalicylic acid (DNS) method.

Results A total of 47 bacterial strains were isolated from the intestine of C. buqueti. Through Congo red staining, eight strains with cellulose-degrading ability were selected, belonging to the genera Bacillus, Brevibacterium, Serratia, and Mammaliicoccus. Among them, strain ZC16 exhibited the strongest β-glucosidase activity, strain ZC34 exhibited the strongest endoglucanase activity, and strain ZC20 exhibited the strongest exoglucanase activity.

Conclusion The intestine of C. buqueti contains abundant cellulose-degrading bacteria with strong enzyme activities, indicating their potential for further development and utilization.