Team:TU-Munich/Project/Biodegradation

Biodegradation is defined as "a process by which microbial organisms transform or alter the structure of chemicals introduced into the environment" (U.S. Environmental Protection Agency, 2009). We work with this concept by degrading or transforming noxious substances in waste water into non-hazardous compounds. These substances, such as antibiotics, hormones or pesticides are not removable by common waste water treatment plants, but there exist enzymes from natural catabolic mechanisms in different microorganisms to inactivate them. To utilize these enzymes we integrated them into a plant as a self-sustaining sedentary organism to create a functional water filter system. To illustrate this approach we chose three potent enzymes:

• The Erythromycin esterase, which degrades macrolides, a persistant group of antibiotics
• The Laccase BPUL, which degrades several noxious substances, for example the artificial hormone ethinyl estradiol, the main ingredient of contraception pills
• The Catechol-2,3-dioxygenase, catalyzing the degradation of aromatic pollutants, which occur in pesticides and insecticides

As ever more third world countries around the globe experience a rapid industrialization without establishing proper environmental practices as well as big companies outsourcing their production facilities in order to avoid expensive sewage treatment the problem of water pollution is more urgent then ever. In order to tackle this problem we were looking for a suitable pollutant which our moss could degrade resulting in a better overall water quality. The organic compund catechol, or 1,2-dihydroxybenzene, met all our criteria as it was a byproduct or raw material in several processes in the chemical industry as well as a stable product of several natural pathways in microbia degrading catechol-like pollutants. Further research into this topic showed that catechol was already a popular target for degredation not only in the iGEM competition but also regarding phytoremediation were it was degraded by Arabidopsis thaliana. Nevertheless we felt that no applicable or effective method to remove catechol from the environment was presented yet, as microbial degredation is unsuitable to establish in poor countries as to its lower cost-effectiveness compared to our moss system. Additionally a removal of the highly soluble catechol through a waterborne moss like Physcomitrella patens seems more fitting then through other plants.

[Edens et al., 1984]

1. [Edens et al., 1984] Edens, L., Bom, I., Ledeboer, A. M., Maat, J., Toonen, M. Y., Visser, C., and Verrips, C. T. (1984). Synthesis and processing of the plant protein thaumatin in yeast. Cell, 37(2):629–33.