Abstract:
Microbiota of termites is crucial for nitrogen cycle activities and degradation of recalcitrant components
of plant biomass that influence soil structure and carbon mineralization in tropical and subtropical
regions. The aim of this study was to isolate and characterize gut bacteria that may be potentially
associated with nitrogen metabolism from two fungus-feeding termites (Macrotermes and
Odontotermes spp.). Twenty termites from the intact colony of each termite species were aseptically
degutted. Gut homogenate was inoculated and cultured on selective media for the isolation of pure
bacteria. Pure bacterial isolates were characterized using their morphological, biochemical and
molecular characters. DNA was extracted from the isolates, polymerase chain reaction (PCR) amplified
and sequenced. The 16S rDNA gene sequences were blastn analyzed against the Genbank database
and phylogenetic analysis was performed using MEGA 5 software. All forty-six isolates reacted positive
for the ammonifying, nitrate, catalase and nitrogenase tests. Phylogenetic analysis grouped the isolates
into three phyla: Firmicutes, Proteobacteria and Actinobacteria. Isolates were affiliated with the genera
Pseudomonas, Citrobacter, Enterobacter, Proteus, Klebssiella, Bacillus, Staphylococcus, Rhodococcus
and Micrococcus. The results confirm that termites harbor diverse gut bacterial groups that have
different physiological/enzymatic activities and might have functional implications in the termitemicrobe
symbiotic association.
