University of Calcutta, India
Piyabrata Sarkar is a Professor in the University of Calcutta, India. Prof. Sarkar completed his Bachelor and Master’s degrees in Chemical Engineering from Jadavpur University, India. He received his PhD degree from IIT Kanpur in 1991. He has taught Chemical Engineering in Jadavpur University, Indian Institute of Technology, Kharagpur and University of Calcutta in various capacities. He has 30 years of research and teaching experience and is a recipient of INSA, DAAD, Wellcome Trust, Commonwealth Fellowship awards. His areas of research interest include design and applications of electrochemical sensors, removal of toxic heavy metals from drinking water and bioremediation
Microbial fuel cells (MFC) are in the focus of interest for last few decades as an alternative source of electricity generation. These bio-electrochemical systems depends on bacterial metabolism of a variety of organic substrates . The electricity generation in MFC mainly depends upon the microbial electrogenicity. Mixed cultures have been reported to generate greater power using specific compounds or organic matter in wastewater and marine sediment in mediator-less MFCs . In the present study, Pseudomonas sp. BT 302 (NCBI Acc. No.JQ782891) and Comamonas sp. BT UA (NCBI Acc. No.GU265556) were used for utilization of uric acid and generation of electricity. Poultry waste soil contains mainly uric acid along with crude protein, crude fibre, calcium, phosphorous etc. Synthetic media with uric acid were prepared as prototype of poultry waste soil and MFC was constructed in a dual-chamber continuous flow design. Three sets of experiments were continuously run with BT UA pure culture, BT 302 pure culture and both microbes mixed culture for comparative study with respect to power generation. Current generation, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were recorded for investigating the anode-biofilm electron transfer behaviour. Total organic carbon (TOC) was determined to evaluate the feasibility of substrate utilization by bacterial strains. The continuous input flow of fresh media and subsequent discard of waste helped to maintain the bacterial growth at equilibrium (average O.D.600 = 1.879 ± 0.095). Microbes were found acclimatized in the fuel cell within 15-18 h having an average CFU of 2×1012 for M-1, 2.16×1014 for M-2 and 1.51×1016 for M-3. Within this time interval the open circuit voltage (OCV) reached a maximum of 582mV for mixed microbes. After 7 days, utilization of substrate resulted in low uric acid, much higher allantoin and highest amount of urea in the waste soup of MFC. The maximum current density and power density were found to be 78.12 mA m-2 and 13.65mW m-2 respectively for mixed culture with the total anodic volume of 1liter against external load of 10kΩ. The optimal external resistance was found to be 806Ω for all three sets. A uric acid-MFC was successful in achieving moderate cell efficiency and continuous power generation. This continuous flow fuel cell would have potential application in power generation and valuable by-product formation through green route.