Isolation and characterization of bacterial diversity from soils supplemented with electrical transformer fluids

Abstract

Repetitive enrichment of soils samples from an agricultural land and newly marked dumpsite on electrical transformer fluid yielded six bacterial species that have the capacity to utilize electrical transformer fluids (askarel) as carbon and energy source. Bacterial species namely:

Micrococcus, Arthrobacter, Pseudomonas putida, Pseudomonas spp, Norcadia and Corynebacterium were identified using morphological and biochemical characteristics. The abilities of these bacterial species to utilize the electrical transformer fluids as carbon source in minimal salt medium (MSM); sub cultured in concentrations of 5, 10, 15 and 20μL of electrical transformer fluids were investigated for twentyâ€Âone days period. Physiological changes in terms of biomass increase were monitored by measuring the pH and optical density of the culture medium. From the results obtained, there was observed a general decrease in the pH and  increase in Optical density (O.D). The mean pH and O.D. readings ranged between (4.34â€Â6.13 and 0.073â€Â0.386) respectively. The decreased pH could justify for the acidic metabolites produced in the course of utilization of askarel as growth substrates. This study suggested that, the tropical ecosystems can provide exotic bacterial species that are capable of degrading or mineralizing polychlorinated biphenyls and their derivatives from dumpsites and agricultural soils.