Analysis of Termite Microbiome and Biodegradation of Various Phenolic Compounds by a Bacterium Isolated from the Termite gut in Louisiana, USA

Abstract

The eastern subterranean termite (EST) Reticulitermes flavipes is an insect pest in the USA. Like all wood-feeding termites (WFT), EST relies on a complex system of microbes to meet its nutritional requirements. The microbiome of WFT is stable, but the relative abundance of bacteria changes depending on diet. The purpose of this study was to explore the microbial diversity within EST collected in Thibodaux and St. Francisville, LA and detect differences based on diet and location to determine if the microbiome has a strict structure. It was found that taxa did not differ much between nearby colonies, but relative abundance is impacted by the wood in the diet. Half of bacteria from the gut of termites on nuttall oak were Bacteroidales, of which 22.7% were members of the family Porphyromonadaceae. 44% of bacteria from termites on red maple were Spirochaetes. All Spirochaetes were members of the genus Treponema. Elusimicrobia, a phylum found exclusively within termites and wood-feeding cockroaches was not abundant in either St. Francisville colony. Taxa differed more between termite colonies from different locations, but the mircobiome of St. Francisville colonies appeared to begin diverging at the family level. Overall, the microbiome was typical of termites, harboring cellulolytic protozoa, nitrogen-fixing bacteria, acetogenic Spirochaetes, and methanogenic archaeans. This has implications in microbial ecology because the organisms are changing, but the function, digestion of lignocellulose, is not. A bacterium was isolated and identified from termite gut as Acinetobacter tandoii from our previous studies degraded various phenolics, including phenol, nitrophenol, dinitrophenol, trinitrophenol, and toluene.