Heavy metals and antibiotics resistance of bacteria isolated from Marchica lagoon: biodegradation of anthracene on submerged aerated fixed bed reactor

Abstract

ABSTRACT Heavy metals resistant and polyaromatic hydrocarbon (PAH)-degrading bacteria isolated from Marchica lagoon. Six isolates, Pseudomonas putida, Orchobactrum antropi, Staphylococus epidermidis, Brevundimonas diminuta, Serratia ficaria and Bacillus anthracis were characterized on the basis of biochemical and 16S rDNA. The strains that showed high resistance to heavy metals were also studied for their antibiotics resistance and growth kinetics. The minimal inhibitory concentrations (MIC) of metals at variant concentrations (10-38 mM) were determined in liquid and solid medium. Strains were showed an extreme resistance against metals with the MIC values of Cu (9 mM), Cd (6.25 mM), Cr (2.5 mM), Ag (0,625), and Hg (0,156). Furthermore, growth rates were decreased in the presence of metals (compared to the control). The anthracene elimination from synthetic wastewater was determined in a submerged aerobic fixed-film reactor. Optimal conditions for bacterium growth and biodegradation of anthracene are determined as: temperature of 37 °C, pH 7, and initial anthracene concentration of 20 mg/l. It emerged that at anthracene concentrations 5-40 mg/l, COD removal efficiency were 84.62%; 90.62%; 91.36% and 71.4% respectively.