Gram-positive anthracene degrading bacteria in the gut of Eisenia fetida

The intestinal system of earthworms has different conditions than surrounding soil and may contain some bacteria which are involved in the biodegradation of organic contaminants such as PAHs. Eisenia fetida possess a variety of enzymes that contribute in breakdown of organic compounds. The aim of this study was to investigate the presence of anthracene degrading bacteria in the gut of Eisenia fetida. The earthworms were exposed to the soil contaminated with 1000 ppm anthracene for 60 days. The live earthworms were then removed and rinsed with distilled water. Then the content of their intestine were removed and its metagenome were extracted. A PCR were carried out using NMR331f and NMR1134r primers which were designated to target conserve region of the gen encodes Naphthalene dioxygenase enzyme which initiates the degradation of anthracene and some other PAHs in gram-positive bacteria. Results indicates that those bacteria possessing the gene existed in the gut of Eisenia fetida. Results showed also that there was no gram positive anthracene-degrading bacteria in the surrounding soil. The existence of those bacteria in the gut of Eisenia fetida was not dependent to the surrounding soil and the bacteria could be found even in the control earthworms which were not exposed to the anthracene contaminated soil. It can be concluded that the gut of Eisenia fetida contain bacteria which are able to degrade anthracene.

Keywords:

Bioremediation , Earthworm , Gut , Intestinal System , Metagenomics , Naphthalene dioxygenase , NMR primers