Watchareeya Thammasorn1, Kronsirinut Rothjanawan2, Pinkaew Siriwong3, Alisa Kongthong4, Pimprapa Chaijak4*
1Faculty of International School of Tourism, Surattani Rajabhat University, Surattani 84100, Thailand
2Department of Computer Engineering, Faculty of Engineering, Princess of Naradhiwas University, Naradhiwat 96000, Thailand
3Mathematics and Data Management Program, Faculty of Science and Digital Innovation, Thaksin University, Phatthalung 93210, Thailand
4Biotechnology Program, Faculty of Science and Digital Innovation, Thaksin University, Phatthalung 93210, Thailand
*Corresponding author’s email: pimprapa.c@tsu.ac.th
Received: 15 October 2025 / Revised: 04 December 2025 / Accepted: 09 December 2025 / Published Online: 23 December 2025
Abstract
Microbial fuel cells (MFCs) represent a promising biotechnological approach for sustainable electricity generation from waste substrates without combustion or secondary pollutant formation. In this study, a kombucha starter culture was employed to convert organic compounds in coconut processing waste into electricity within a carbon-capture MFC integrated with the green microalga Chlorella sp. BF03. The electrochemical performance of the MFC was evaluated according to Ohm’s law. By-products, carbon fixation rates, and degraded metabolites of the waste were also analyzed. The maximum current density and power density of the system were 6.40 ± 0.01 A/m2 and 0.77 ± 0.02 W/m2 respectively, with Komagataeibacter saccharivorans and Acetobacter tropicalis as the main bacterial cultures. No harmful compounds were detected among the degraded metabolites. The system achieved a maximum carbon fixation rate of 0.13 ± 0.00 g/L/day and a bacterial nanocellulose production rate of 0.54 ± 0.04 g/L/day accompanied by total chlorophyll a and b contents of 0.31 ± 0.01 µg/L and 0.32 ± 0.02 µg/L, respectively. Biomass extracts contained various nutraceuticals, including limonene, n-hexadecanoic acid, octadecanoic acid and vitamin E. These results demonstrate the potential of kombucha-based carbon-capture MFCs for integrated energy generation, waste valorization, and production of high-value bioproducts.
Keywords: Agricultural waste, By-product, Electricity generation, Fatty acid, SCOBY, Upcycling
