Isolation and characterization of Rhodococcus qingshengii, a cellulolytic bacteria from Cnaphalocrocis medinalis (Lepidoptera: Crambidae) gut

Abstract

Herbivorous Lepidopteran insects depend on microbial cellulases for cellulose digestion. The present study aimed to investigate the herbivorous Lepidoptera Cnaphalocrocis medinalis gut for isolation of cellulose degrading bacteria. A Gram positive rod, non-motile, mesophilic, neutrophile bacterial strain TCI11 was isolated from C. medinalis (Lepidoptera: Crambidae) 5^th instar larvae gut. The isolate was found to be a potent cellulose degrader, which was isolated on carboxymethylcellulose agar medium using carboxymethylcellulose as a sole carbon source and screened by Congo red and Gram’s iodine dye staining method. The cellulose degrading strain was characterized on the basis of Gram staining, morphological and biochemical properties. Based on 16S rRNA gene analysis, the strain was found to be most closely related to Rhodococcus baikonurensis, Rhodococcus erythropolis, Rhodococcus globerulus (99.77, 99.35 and 99.06% similarity, respectively) and was identified as Rhodococcus qingshengii. R. qingshengii is being reported for the first time as a potent cellulose degrader. The source of isolation of this particular bacterial strain is also novel.