UPSC CSE Prelims 2011
Microbial Fuel Cells (MFCs) are considered a sustainable energy source due to their unique operational principles:
Statement 1 is correct: MFCs utilize living microorganisms, primarily bacteria, as biocatalysts. These microbes oxidize organic substrates, such as glucose or organic waste, in an anaerobic environment. During this metabolic process, electrons are released and subsequently transferred to an anode, generating an electrical current. This biological conversion of chemical energy into electrical energy is a core aspect of their sustainability.
Statement 3 is correct: MFCs can be effectively integrated into wastewater treatment plants. In such applications, they serve a dual purpose: treating organic pollutants present in wastewater by degrading them, and simultaneously producing electricity. This capability offers an environmentally friendly approach to waste management while also generating renewable energy, contributing significantly to their sustainability profile.
Statement 2 is incorrect: MFCs primarily rely on organic materials as substrates for microbial metabolism and electricity generation. The microorganisms require carbon-based compounds for their metabolic processes. While specific designs might involve certain inorganic electron acceptors or mediators, the fundamental energy source for MFCs is organic matter, not a wide variety of inorganic materials.
Option (a) is incorrect because statement 3 is also correct.
Option (b) is incorrect because statement 2 is false, and statement 1 is correct.
Option (d) is incorrect because statement 2 is incorrect.