Preliminary Study of Bioelectricity Generation Using Lettuce Waste as Substrate by Microbial Fuel Cells

Abstract

Agricultural waste negatively impacts the environment and generates economic difficulties for agro-industrial companies and farmers. As a result, it is necessary for an eco-friendly and sustainable alternative to managing this type of waste. Therefore, the research aimed to investigate lettuce waste as an alternative substrate to generate bioelectricity in single-chamber microbial fuel cells (scMFCs). It was possible to report voltage and electric current peaks of 0.959 ± 0.026 V and 5.697 ± 0.065 mA on the fourteenth day, values that were attained with an optimum pH of 7.867 ± 0.147 and with an electrical conductivity of 118.964 ± 8.888 mS/cm. Moreover, as time passed the values began to decline slowly. The calculated value of maximum power density was 378.145 ± 5.417 mW/cm2 whose current density was 5.965 A/cm2, while the internal resistance reported using Ohm’s Law was 87.594 ± 6.226 Ω. Finally, it was possible to identify the Stenotrophomonas maltophilia bacterium (99.59%) on a molecular scale, as one of the microorganisms present in the anodic biofilm. The three microbial fuel cells were connected in series and demonstrated that they were capable of lighting an LED bulb, with a voltage of 2.18 V.

Obtaining Sustainable Electrical Energy from Pepper Waste

“…The values of the electric current decrease when the organic matter is depleted because the microbes lose their nutrients to carry out their metabolism and release electrons to the medium [38]. Lettuce waste has been reported as substrates in MFCs, generating electrical current peaks of 5.697 ± 0.065 mA, mentioning that the corrosion of the metal electrodes in the last days of the operation of the MFCs influenced the decrease in its current values [39]. Abubakar et al (2023) reported that the absence or low concentration of exoelectrogenic microbes or other types of microorganisms with high concentrations of organic matter leads to the low efficiency of the MFCs, and the absence of microorganisms is due to the inadequate choice of the standardization of the pH value during the operation of the MFCs [40].…”

Activated Carbon Electrodes for Bioenergy Production in Microbial Fuel Cells Using Synthetic Wastewater as Substrate

“…In the following days, the values experienced a gradual decrease until they produced 1.93 mA on day 30. The peak current values shown in the first days are attributed to the good formation of the electrogenic biofilm [46], which depends largely on the measurement of the carbon sources present in the substrates [47], which act as an energy supply in the biological process of microorganisms to produce electric current [48]. As the organic compounds decrease, the production of electrons is reduced, thus generating a lower electrical current in the last few days [49].…”

Sustainable Electricity Production Using Avocado Waste

“…Currently, the large scientific community has begun to use different types of waste as fuel, but in recent years, agricultural waste has become relevant for its use as fuel. Recently, Rojas-Villacorta et al (2023) reported that using vegetable waste, for example lettuce, as a substrate in MFCs and Cu and Zn electrodes can generate current and voltage values of 5.697 ± 0.065 mA and 0.959 ± 0.026 V [20]. Likewise, Aleid et al ( 2023) used fruit waste mixtures as fuel, generating peaks of 0.125 V on day 25 in their single-chamber MFCs with graphite electrodes [21].…”