The Occurrence of Crude Oil-Degrading Bacteria in Some Sponges Collected at the Persian Gulf: Ecological Importance and Biotechnological Application

Abstract

The Persian Gulf is the most critical aquatic environment in the world. The relationship between marine animals and degrading bacteria not well understand. The purpose of this investigation is the description of symbiont crude oil-degrading bacteria in some sponges in the Persian Gulf. Marine sponges were collected from four stations at the Persian Gulf. Symbiont crude oil-degrading bacteria were isolated from marine sponges by enrichment in ONR7a medium after four subcultures. The isolated bacteria were identified by biochemical and molecular methods. The degradation of crude oil was determined by spectrophotometric, gravimetric, and GC-FID methods for each strain. In this study, 38 crude oil-degrading bacteria were isolated from 8 sponge samples. The efficient strains that had the highest crude oil degradation belonged to the genus Cellulosimicrobium, Shewanella, Alcanivorax and Cobetia. The GC-FID analysis confirmed that the strains IAUK3532, IAUK3537 and IAUK3519 exhibit maximum degradation of crude oil (respectively, 94.5%, 88.13% and 85%). It is observed that when the concentration of crude oil increased, the degradation decreased. It can be concluded from these results that the microbes that coexist in the sponges located at the Persian Gulf can degrade crude oil. These symbionts crude oil-degrading bacteria can be applied to decrease the oil pollution in the Persian Gulf. Also, the symbiotic relationship between sponges and crude oil-degrading bacteria increases sponge survival and contributes to the development of their colonies in the Persian Gulf.