Impact of Inorganic Nutrients and Heavy Metals Present as Co-contaminants on Biodegradation of Petroleum Hydrocarbons by Phormidium ambiguum Strain TISTR 8296

Abstract

The purpose of this research was to evaluate the biodegradation extent of petroleum hydrocarbons by Phormidium ambiguum strain TISTR 8296 in the presence of inorganic nutrients and heavy metals as co-contaminants. In this context, waste motor oil served as a source of petroleum hydrocarbons. Strain TISTR 8296 grew actively with waste motor oil at 0.5–2.0% (v/v) concentrations and also exhibited good biodegradation potential at this concentration range. Meanwhile, its growth and biodegradation capacity fell down with increasing oil concentration to 3.0 and 4.0%. Strain TISTR 8296 adapted quickly to pH changes, showing good growth ability and biodegradation capability at a pH range of 4.0–9.0 with an acidic pH of 4.0 and 5.0 appearing to decelerate its biodegradation efficiency. The addition of PO4 3− and NO3 − exerted a strong stimulatory effect on growth and biodegradation efficiency, while a slight promoting effect was observed for NO2 −. By contrast, amendment of NH4 + as well as heavy metals caused a substantial inhibitory effect on growth and biodegradation efficiency with NH4 + and Mn(II) appearing to show a weak suppressing effect. GC-MS analyses indicated that strain TISTR 8296 could transform and degrade both aliphatic and aromatic compounds.