Engineering electroactive microbes for environmental sensing.

Abstract

Environmental contaminants, including pesticides, endocrine disruptors, and industrial chemicals, cause thousands of illnesses and deaths annually. Unfortunately, exposures are often detected by monitoring degradation products in blood and urine, with few effective methods for detection and remediation at the point of contamination. We have developed innovative strategies to remediate these compounds. In one specific engineered microbial technology, we have targeted detection and destruction of pesticides. This system is based upon microbial electrochemistry using two engineered strains. The strains are combined such that the first microbe (E. coli) degrades the contaminant, while the second (S. oneidensis) generates current in response to the degradation product without requiring external electrochemical stimulus or labels. This cellular technology is unique in that the E. coli serve only as an inert scaffold for enzymes to degrade pesticides, circumventing a fundamental requirement of co-culture design: maintaining the viability of two microbial strains simultaneously. We can detect OP degradation products at sub-micromolar levels, outperforming reported colorimetric and fluorescence sensors. This, and our similar bioengineered technologies, enable detection and degradation of dangerous environmental contaminants.