Design of microbial fuel cell for power generation using milk and Lactobacillus bacteria

Abstract

This study investigates the use of milk as a substrate in a Microbial Fuel Cell (MFC) for power generation with Lactobacillus bacteria. In place of semipermeable membrane separating the anodic and cathodic chamber in MFC, salt bridge made from agar-agar gel is used as a conducting medium. KMnO₄ is used as an oxidizer in cathodic chamber in MFC and open circuit voltage (OCV) is observed for various systems by changing anodic and cathodic chamber volume, bacterial concentration. Maximum OCV of 2.01 V is obtained with 300 million Lactobacillus sporogenes added to anode of 600 mL working volume containing 100 mL milk and 500 mL water mixture. Novel approach was used to design new structure of salt bridge which can act as conducting medium and also as a cathode. This system achieved a maximum OCV of 1.13 V. Sodium hypochlorite (0.6 w/v%) has been evaluated as an alternative oxidant to potassium permanganate, achieving a maximum OCV of 1.66 V. The obtained results depicted that the milk as a substrate in MFC along with Lactobacillus has considerable power generation scope which can be further improvised.