Bioremediation of phenol from synthetic and real wastewater using Leptolyngbya sp.: a comparison and assessment of lipid production

Bioremediation of wastewater is gaining popularity over chemical treatment due to the greener aspect. The volume of literature containing algal biodegradation is small. Especially, removal of toxic materials like phenol from coke-oven wastewater using fast-growing cyanobacteria was not tried. The current study, therefore, targeted at bioremediation of phenol from wastewater using Leptolyngbya sp., a cyanobacterial strain, as a finishing step. Furthermore, the growth of the strain was studied under different conditions, varying phenol concentration 50-150 mg/L, pH 5-11, inoculum size 2-10% to assess its ability to produce lipid. The strain was initially grown in BG-11 as a reference medium and later in phenolic solution. The strain was found to sustain 150 mg/L concentration of phenol. SEM study had shown the clear difference in the structure of cyanobacterial strain when grown in pure BG-11 medium and phenolic solution. Maximum removal of phenol (98.5 +/- 0.14%) was achieved with an initial concentration 100 mg/L, 5% inoculum size at pH 11, while the maximum amount of dry biomass (0.38 +/- 0.02 g/L) was obtained at pH 7, initial phenol concentration of 50 mg/L, and 5% inoculum size. Highest lipid yield was achieved at pH 11, initial phenol concentration of 100 mg/L, and 5% inoculum size. Coke-oven wastewater collected from secondary clarifier of effluent treatment plant was also treated with the said strain and the removal of different pollutants was observed. The study suggests the utilization of such potential cyanobacterial strain in treating industrial effluent containing phenol.