Variation of Microcerotermes diversus Silvestri (Isoptera: Termitidae)Gut Bacteria and Isolation of Gut Lignin-Degrading Bacteria

Lignin is the most abundant aromatic (phenolic) polymer and the second most plentiful raw material in the terrestrial environment. It is degraded by bacteria and fungi in the natural world.  To evaluate whether the role of symbiotic bacteria in lignin degradation among termites, four colonies of Microcerotermes diversus Silvestri (Termitidae) were collected from traps in Ahvaz, Bandar Abbas, and two islands of Khark and Kish. Sample suspensions were prepared from guts in 5 ml D.H2O. The samples were cultured on nutrient agar (NA) medium. The plates were incubated at a temperature of 270C for 24-72 h. Different types of bacteria with different colony morphologies were selected and purified. To differentiate lignin-degrading bacteria, all 47 bacterial isolates were grown on different extracted lignin agar containing MSM. In total, 45 isolates were positive for lignin degradation. Culture-independent 16S rDNA sequencing in combination with classical culturing methods were applied to identify the bacteria. These were assigned to genus/species Stenotrophomonas maltophilia, Elizabethkingia anopheles, Ochrobactrum anthropic, Serratia marcescens, Lysinibacillus pakistanensis, Actinetobacter pitti, Pseudomonas spp., and Bacillus spp.  To specify the amount of ligninolytic activity, family selected bacteria were grown on lignin agar medium.  Dye decolorization in culture plate assays with Methylene Blue was evaluated. Clear zones in agar around the isolates were measured.