Team:UANL Mty-Mexico/Project

Abstract

One of the major environmental problems in northern Mexico is arsenic contamination of groundwater. Several projects have previously aimed to biorremediate heavy metals and metalloids using bacteria, but without scalable potential due to the lack of an efficient cell recovery system. We aim to develop an easy-to-recover arsenic biosensor and chelator. Recovery strategy will consist of a new adhesion mechanism that enables bacteria to bind to silica surfaces through the expression of the L2 ribosomal protein, attached to the outer membrane protein AIDA-I. A quantifiable, highly-sensitive luciferase-based reporter system coupled to an oligomeric metallothionein is expected to increase our system’s capability of arsenic sensing and chelation.

Overview

Arsenic is an invisible, tasteless, odorless, frequently undetectable but highly toxic contaminant, even at small concentrations (NRC, 1999). Drinking of arsenic-contaminated water is associated with various kinds of cancer; acute arsenic poisoning produces vomiting, oesophageal and abdominal pain, and bloody diarrhea. It is therefore a severe cause for concern in many countries of the world including Argentina, Bangladesh, Chile, China, India, Mexico, Thailand and the United States of America (WHO, 2012).

In Mexico, sources of drinking water exceeding 50 ug/L have been found in several cities, included Monterrey (our hometown) and many other regions (figure 1) mostly in northern Mexico (Camacho et al. 2011). The maximum contaminant level (MCL) in Mexico is 25 ug/L since 2005 (SSA, 2000); although in the USA the MCL is 10 ug/L, which according to the WHO is a reasonable expectation achievable by conventional treatment.

Our project, E.cologic, addresses this severe health public issue through an environmentally friendly, scalable biological device. It will be divided into three main modules: detection, capture and recovery. Each of them can be used as a separate tool; we are then to construct a biorremediation kit whose parts are potentially useful for other purposes.

Figure 1. Mexican regions affected by Arsenic contamination of drinking water.