Abstract:[Background] Mole crickets (Gryllotalpa spp.) are widely distributed agricultural underground pests in China, and the composition of their gut bacteria and the functional bacterial resources remain to be studied. [Objective] To obtain the culturable bacteria from the gut of G. orientalis, screen out the strains capable of producing cellulase, measure the cellulase activities of the strains, and explore the culture conditions of the strains with high cellulase activities. [Methods] The gut bacteria of G. orientalis were isolated by the culture method and identified by methods of molecular biology. The cellulose-producing strains were screened by the carboxymethylcellulose sodium (CMC-Na) hydrolysis assay, and the cellulase activity was determined by the 3,5-dinitrosalicylic acid (DNS) method. [Results] A total of 23 strains were isolated from the gut of G. orientalis, belonging to 10 species of 7 genera (4 species of Bacillus and 1 species of Enterococcus, Staphylococcus, Acinetobacter, Proteus, Enterobacter, and Lactococcus, respectively). The results showed that all the 22 strains except strain N18 had cellulase-producing capacity, among which strains N3 and N14 had the strongest cellulase-producing capacity, followed by N15 and N21. The medium pH, culture time, and inoculum amount had different effects on the cellulase production. Within the ranges set in this study, strains N3 and N14 always had the highest cellulase production under the influences of different single factors. [Conclusion] The gut of G. orientalis harbors rich culturable bacterial resources, and 95% of the isolates of gut bacteria have the function of producing cellulase. Among the isolates, Bacillus subtilis N3 and N14 with the highest cellulase production demonstrate the most potential for development.
