Enhanced Biodegradation of Crude Oil in Seawater by Using Microbial Consortia

Abstract

A biodegradation study was performed to assess the biodegradation of crude oil in seawater by consortium of Candida tropicalis RETL-Cr1, Pseudomonas aeruginosa BAS-Cr1 and Chromobacterium violaceum MAB-Cr1. Two independent experiments using different growth substrates, 5 mM glucose and 5% (v/v) crude oil, were undertaken to compare the microbial growth profile. The study was carried out using shake flask culture at 30°C, agitated 200 rpm. Microbial growth profile was monitored by measuring the optical density (OD600) on hourly and weekly basis. Biodegradation efficiency and rate were quantified by comparing the initial and final crude oil concentration, whereas the degradation of selected aliphatic hydrocarbons was quantified by comparing the initial and final area in chromatogram. The biodegradation ratios were monitored using Gas Chromatography Mass Spectrometry (GC-MS) method. Present finding showed that glucose was completely utilized at T10. However, the consortia can growth in crude oil even after 28 days. Overall biodegradation efficiency is 69.74% while the overall biodegradation rate is 24.85 g/L/d. The consortia could degrade 37% of n-alkane in crude oil after 28 days. Besides, biodegradation ratios shown that biodegradation had took place throughout the degradation period. It can be concluded that the consortia have high potential to degrade crude oil efficiently.