Potential of newly isolated wild Streptomyces strains as agents for the biodegradation of a recalcitrant pharmaceutical, carbamazepine.

ABSTRACT

Carbamazepine (CBZ) is a recalcitrant xenobiotic pharmaceutical pollutant highly stable in soil and wastewater during treatment. The biodegradation of CBZ using streptomycetes has been few studied up to now. Sixteen newly filamentous bacteria belong to genus Streptomyces spp. isolated from different Romanian soil samples and three strains from a collection of microorganisms (MIUG) were morphologically characterized, tested based on their resistance against CBZ toxicity and then selected as agents for bioremediation. Five Streptomyces spp. strains coded MIUG 4.88, MIUG 4.89, SNA, LP1 and LP2 showed CBZ tolerance at all of the tested concentrations, i.e. 0.05, 0.2, 1, 5 and 8 mg L⁻¹. Two of these (MIUG 4.89 and SNA strains) were selected based on their resistance to target compound and were then assessed for CBZ biodegradation. The strain Streptomyces MIUG 4.89 showed an interesting efficiency for CBZ removal, with a yield of 35% when it was cultivated in submerged conditions on a minimal medium supplemented with 5 g L⁻¹ glucose. This ability was linked to extracellular laccase production. These results are promising for the use of these filamentous bacteria as bioremediation agents.