Diversity and functional profiling of culturable cellulolytic bacteria in wood-feeding termites (Order: Blattodea)

Abstract

Termites are a large and diverse group of phytophagous insects that feed on cellulose-rich organic materials. During the decomposition of organic matter, they rely on symbiotic microorganisms, particularly bacteria and protozoa present in their digestive tract, to facilitate cellulose degradation. This study aims to identify the cellulolytic bacteria from the gut of the wood feeding termite species based on sequences of 16S ribosomal RNA (rRNA) gene. Berg’s agar media supplemented with carboxymethyl cellulose (CMC) was used to culture the cellulose degrading bacteria. Cellulolytic activity was confirmed based on clear zone formation and the cellulolytic index on Berg’s agar media using Congo red assay. Total nine isolates of bacteria from the gut of wood feeding termites showed cellulolytic activity. The highest cellulolytic index was recorded in Bacillus cereus (CI- 1.31), followed by Bacillus subtilis (CI-
1.09). The high cellulolytic index in these isolates is likely owing to their ability to secrete greater amounts of cellulases, which degrade the amorphous regions of cellulose in the CMC substrate.