Biodegradation of a Nigerian Crude Oil by a Micro Alga and a Cyanobacterium

Abstract

This study investigated the ability of pure and co-cultures of the eukaryotic green microalga Chlorella and the Cyanobacterium, Chroococcus sp. (Anacystis) obtained from a freshwater system in the Niger Delta, to degrade a Nigerian crude (Bonny Light) in a batch system for a 28-day period. Biodegradation experiments were carried out using BGII medium with pH range of 6.0-7.7. At day 28 percentage primary biodegradation of Chlorella, Chroococcus, co-cultures, and control, were 64.8%, 67.69. 69.8% and 3.8% respectively. Percentage of total organic carbon lost in these systems at day 28 were 64.8%, 67.9%, 80.9% and 2.9% respectively. The percentage of hydrocarbon levels of these systems remaining at day 28 were 26.7%, 16.7% 10.0% and 97.5% respectively. These results showed that there was no significant difference (P>0.05) between percentage primary biodegradation, total organic carbon and crude oil losses between cultures of Chlorella, Chroococcus and co cultures of both organisms. Thus both organisms may be used separately in the bioaugumentation protocol for remediation of crude oil contaminated aquatic systems. The use of co-cultures of both organisms did not offer any significant (P>0.05) advantage over the use of pure cultures of both organisms.

Keywords: eukaryotes, prokaryotes, pure cultures, co-cultures, cyanobacteria, algae.

Tropical Freshwater Biology Vol. 16 (1) 2007: pp. 17-30