Bio-electrochemical Characterization of Indigenous Bacteria from Tofu Wastewater in Dual-Chamber Microbial Fuel Cells with HCl-Activated Carbon Anodes

Fahmi Fatkhomi; Putut Marwoto; Sunyoto Eko Nugroho; Surani Abu Bakar

doi:10.21009/1.12112

Authors

Fahmi Fatkhomi Science Education Study Program, Universitas Pancasakti Tegal
Putut Marwoto Doctoral Study Program in Natural Sciences, Universitas Negeri Semarang, Indonesia
Sunyoto Eko Nugroho Physics Education Study Program, Universitas Negeri Semarang, Indonesia
Surani Abu Bakar Nanotechnology Research Centre, Faculty of Science & Mathematics, Universiti Pendidikan Sultan Idris, Malaysia

DOI:

https://doi.org/10.21009/1.12112

Keywords:

Microbial Fuel Cell, Tofu Waste, Indigenous Bacteria, Biofilm, Activated Carbon, Renewable Energy

Abstract

Tofu liquid waste is a high-content organic pollutant that has the potential to become a renewable energy source through Microbial Fuel Cell (MFC) technology. This study aims to characterize the bio-electrochemical performance of indigenous bacteria from tofu waste in a Dual-Chamber MFC (DCMFC) system using recycled carbon anodes from spent batteries. The innovation of this research lies in the electrode activation through a combination of thermal and chemical treatments (32% HCl for 12 hours) to increase surface porosity and biocompatibility. The system utilized a 17 cm salt bridge with a 7% (w/v) agar and 15% (w/v) NaCl matrix. The results showed a highly consistent increase in Open Circuit Voltage (OCV), rising from 48.0 mV to a peak of 231.0 mV at the 31st hour. Linear regression analysis indicated an average growth rate of 4.81 mV/hour with a very high coefficient of determination ($R^2$) of 0.9066, indicating excellent stability in ionic and electrical conduction. Qualitatively, the formation of a macroscopic, wax-like biofilm was observed on the anode surface at the end of the observation period, providing physical validation for the surge in the system's electrical performance. This study proves that engineered recycled electrodes and the utilization of local indigenous bacteria are capable of generating stable and progressive electrical energy.

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