Concerns about Earth’s climate change and environmental pollution have provoked the search for new power sources

such as microbial fuel cells (MFCs)

which offer a clean energy alternative. Hence

the development of an eco-friendly MFC which utilizes or recycles natural materials is required. The MFC was designed as a single chamber that contains soil (electrolyte media)

a cathode electrode (graphite rod)

and an anode electrode (zinc cylinder) as one unit in experiments. The soil in the MFC was adjusted to pH 7–8

and the moisture content was maintained at 70% of soil field capacity. The MFC units were incubated at 25–30°C. To optimize electrical generation

three sequential experiments were conducted in triplicate by testing different ratios of charcoal

gypsum

and sheep manure. A Fluke 175 multimeter was used to measure direct current voltage and current across the anode and cathode in a closed circuit.The results of optimization were then applied to construct MFC units for two further experiments

which were powering light-emitting diodes (LEDs) and a clock. The voltage generated ranged from 1.96 to 2.85 Volts (V) and the current ranged from 0.055 to 0.17 milliampere (mA) (0.108–0.485 milliwatts [mW]) during the 180-day in the LEDs experiment

and from 0.69 to 1.88 V and 0.068 to 0.242 mA (0.047–0.455 mW) during the 250-day in the clock operated experiment. The MFC showed a potential for continuous power supply

waste recycling

soil properties improvement

and soil nutrient enrichment. The power harvest may offer advantages for renewable energy that can operate apparatus that needs low voltage and current.