Crude oil contamination of soil is a major concern for tea industry in Assam, India. Crude oil is a persistent organic contaminant which alters soil physical and biochemical characteristics and makes tea plants more susceptible against crude oil contamination. Therefore, two native bacterial strains designated as AS 03 and NA 108 having crude oil degradation ability was isolated from crude oil contaminated soil. Isolates were evaluated for reduction of crude oil phytotoxicity and soil bioremediation. Biochemical and 16s ribosomal ribonucleic acid (rRNA) analysis confirmed that the bacterial strains belong to Pseudomonas aeruginosa. Under in vitro evaluation, it was found that both the strain could tolerate crude oil up to 40% (v/v). However, structural changes including morphology, difference in number of colonies were found in the presence of hydrocarbon in both AS 03 and NA 108. Also, an improvement in growth of bacterized tea plants was observed compared to non-bacterized plants grown in crude oil contaminated soil. The cumulative increment in height was 5 to 42%, compared to non-bacterized plants and with significantly higher root and shoot dry biomass accumulation. Soil treatment with both AS 03 and NA 108 improved soil quality including organic carbon, conductivity, pH and degradation of total petroleum hydrocarbon (TPH) of the contaminated soil. These findings suggest that the tested bacteria can be exploited for bioremediation of crude oil contaminated soil in the geographical region of Assam.
Keywords: Pseudomonas, tea plant, total petroleum hydrocarbon, crude oil
African Journal of Biotechnology Vol. 12(19), pp. 2600-2610