Indigenous Bacillus paramycoides and Alcaligenes faecalis: potential solution for the bioremediation of wastewaters

Farmers near towns and cities are using wide range of untreated wastewaters for crop irrigation in Pakistan due to severe freshwater shortage. The present study aimed to treat different types of wastewater including domestic, hospital, textile, pharmaceutical and mixed wastewaters using indigenous bacterial isolates to remove contaminants and render these wastewaters safer for irrigation. 37 bacterial strains were isolated from the 5 wastewater samples collected from different sites in Lahore, Pakistan. Under optimum growth conditions, the isolates D6, D7 and P1 showed maximum decolourisation potential of 96, 96, 93 %, respectively against hospital wastewater. GCMS analysis of the untreated hospital wastewater confirmed the presence of pharmaceutic pollutants i.e. Phenol, Salicylic acid, Caffeine, Naproxen, Octadecene and Diazepam. These organic compounds were biodegraded into derivate Ticlopidine in the case of isolate D6, derivatives Tetradecene and Griseofulvin in the case of isolate D7, and derivatives Lidocaine and Butalbital in the case of isolate P1. 16S rDNA sequencing was used to identify these isolates. Isolates D6 and D7 showed 100 and 99.86 % homology to Bacillus paramycoides, a novel strain from Bacillus cereus group (Liu et al., 2017). Isolate P1 showed 97.47 % homology to Alcaligenes faecalis. These strains therefore could represent a low-cost and low-tech alternative to bioremediate complex wastewaters prior to irrigation to support the achievement of the Sustainable Development Goal 6 - clean water and sanitation in Pakistan.