Enzyme-Mediated Transformation of 17 Beta-Estradiol in Soil.

Widespread presence of reproductive hormones in soil and natural water bodies is gaining attention as it has the potential of influencing public health and environment. Increasing concentration of these hormones in the environment is of foremost concern as they interfere with normal biological behavior of human, aquatic, and wildlife animals. Among sexual steroidal hormones 17-beta estradiol (E2) is the most potent, and is persistent in environment. Land application of estrogen-containing solid wastes (eg. animal manure) is considered as a major entry pathway of these hormones to natural water bodies via- surface runoff and/or leaching. Transformations of these hormones in soil impact their presence in water bodies. Previous studies show that extracellular enzymes are capable of transforming persistent chemicals into non-harmful products, indicating that enzymes produced by microorganisms may play an important role in transformation of hormones. We conducted experiments to examine the transformation of radiolabeled  and non-labeled E2, in well characterized sandy loam soil to which Laccase or Horseradish Peroxidase was added. Additional experiments were also done to assess the impact of organic matter on these enzyme-mediated reactions and to identify optimum enzyme activity.Very low concentration of both radiolabeled and non-labeled E2 in soils treated with enzymes was found as compared to control. This study aims toward providing a better understanding of fate of hormones in environment and to develop a efficient and eco-friendly bioremediation technique using enzymes.