Bioprospection of sulfate-reducers and metal-reducers from acidic and alkaline sites: biotechnological applications for the treatment of metal and metalloid containing wastes – BIOMETAL

All over the world there is a crescent interest for clean technologies as microbial-based remediation and treatment processes. These technologies can be applied to metal and metalloid contaminations that can be a source of metal inputs for surface and groundwaters. Nevertheless, one of the features of many metal contaminated sites, such as acid mine drainages (AMD), geothermal spills and some industrial wastes, is their strong acidity or alkalinity. This makes the use of most of the existing systems useless because the microorganisms are not adapted to such conditions. The relevance of BIOMETAL project is based on the bioprospection of acidophilic/alkaliphilic microorganisms, from anthropogenic contaminated sites (AMD in Carnoulès, France), natural alkaline lake (Parangueo, Mexico) as well as from natural metal-contaminated acidic thermal springs (“Los Azufres”, Michoacan, Mexico). This bioprospection will be conducted in the view of developing bioprocesses for chromium and arsenic reduction and removal under acidic or alkaline conditions. The knowledge of microbial populations adapted to these environments is of great interest to promote and improve bio-treatments.
Arsenic and chromium are two of the main metal contaminants in Mexico surface and groundwaters as well as in AMD systems or industrial wastes all over the world. BIOMETAL will focus on the microorganisms that could be used in the treatment of such contaminants by direct or indirect reduction and precipitation. Among the bio-processes, applicable to metal removal or attenuation the most efficient and promising use sulfate- or sulfur-reducing prokaryotes (metal reduction and precipitation with sulfide). According to the knowledge (metal bioprocesses) and the relevant environmental issues, BIOMETAL also aims to investigate the microorganisms of interest in terms of chromium and arsenic reduction.
In order to achieve these goals, BIOMETAL is organized into four experimental tasks including 1/ acidic and alkaline sites characterization (task2), acidophilixc and alkaliphic sulfate-, sulfur-, and metal reducers isolations and characterizations (task 3), design and optimization of bioreactors for the arsenic removal under acidic conditions (Task4) and chromium removal from industrial wastes (Task5).