Being constituents of the effluents of many industries, heavy metals cause severe environmental pollution given the fact that they are recalcitrant and persistent in the environment. Conventional remediation strategies used to treat heavy metals loaded wastewater are neither economical nor environmentally friendly. To overcome these challenges, the rise of a new process that combines energy conservation and recovery was mandatory. Microbial fuel cells have emerged as a promising technology to mitigate environmental pollution; it provides a solution to wastewater treatment and the removal and/or recovery of heavy metals. They are bioelectrochemical systems that utilize the catalytic activity of microorganisms organized in biofilms to oxidize organic or inorganic compounds by producing electric current, thus providing a new opportunity for sustainable energy production and bioremediation. The removal and recovery of metals, such as Cr(VI), V(V), and Cu(II) have been evaluated using both single and double chambered MFCs. The fact that some heavy metals have high redox potential makes it possible to utilize them as effective electron acceptors instead of oxygen in the cathodic chamber of microbial fuel cells. Biotic/Abiotic cathode chambers can not only remove but also recover heavy metals. However, a number of challenges such us: low production rates and limited efficiencies make the application of this technology restricted to lab scale only. In this chapter, we review the removal/recovery of metals from effluents using the microbial fuel cells technology. We'll first summarize the principle of metal removal/recovery in microbial fuel cells, and then provide an overview of literature that attempted to treat metal loaded effluents in both single and double chambered microbial fuel cells while discussing power output, heavy metal removal efficiency and mechanisms involved in the process. Furthermore, the main challenges facing microbial fuel cells and their future applications in the treatment of heavy metals contaminated wastewater will be outlined.

Pseudomonas aeruginosa has a high propensity to develop biofilms that are resistant to exogenous deleterious agents. The aim of this study was to investigate whether carvacrol and thymol can interfere with adherence phenomena as well as acting on biofilm formation. Tests of P. aeruginosa strains showed that carvacrol and thymol interferes with the starting phases of adherence as well as with P. aeruginosa biofilms. Carvacrol and thymol (2MIC) inhibition was 97±8.5 and 89±6.3% for P. aeruginosa (ATCC 27853)and 72±4.6 and 69±6.8% for P. aeruginosa (CIP A22) adherence respectively. Carvacrol (2MIC) inhibition exceeds 90% for P. aeruginosa (ATCC 27853) and P. aeruginosa (IL5)biofilm. Thymol (2MIC) inhibition is 86±2.1, 54±5.9 and 70±4.3% for P. aeruginosa (ATCC 27853) P. aeruginosa (CIP A22), P. aeruginosa (IL5), respectively. Key words: Biofilm, adherence, carvacrol, thymol, Pseudomonas aeruginosa.

The initial interaction between microorganisms and substrata is mediated by physicochemical forces, which in turn originate from the physicochemical surface properties of both interacting phases. In...