Banana Waste-to-Energy Valorization by Microbial Fuel Cell Coupled with Anaerobic Digestion

Abstract

Banana is the most cultivated fruit plant in the world. It is produced in Latin America, Asia and Africa. India and China are the world’s largest banana producers, with almost 41% of the world’s production. This fruit reaches a total world production of 158.3 million tons per year. However, during their production cycle, the banana agroindustry produces large volumes of solid waste derived from overripe fruit. It contributes between 8–20 percent of the waste (around 100 kg of banana waste for every ton of banana produced). Therefore, the use of overripe banana waste represents a huge opportunity for bioenergy production. This work demonstrates that banana waste can be further used for power generation using a microbial fuel cell (MFC) coupled with anaerobic digestion (AD). First, the maximum methane production (MMP), methane production rate (MPR) and biochemical methane potential (BMP) were measured using an anaerobic batch bioreactor for 64 days of monitoring. Finally, the digestate generated from AD was used in the MFC to determine the polarization curve, maximum voltage, maximum power density (MPD), resistance and current. As a result, the AD generated an MMP of 320.3 mL, BMP of 373.3 mLCH4/gVS and MPR of 18.6 mLCH4/Lb⋅day. The MFC generated 286 mV (maximum voltage), 41.3 mW/m2 (MPD), 580.99 Ω (resistance) and 0.0002867 A (current). Both processes together produced a total bioenergy of 13.38 kJ/gVS. This coupled system showed a suitable and promising use of banana waste for ecofriendly bioenergy generation. Therefore, this feedstock could be taken advantage of for generating sustainable processes and developing a circular economy in the banana agroindustry.

Bioenergy, Electricity, Biogas Production, and Emission Reduction Using the Anaerobic Digestion of Organic Municipal Solid Waste in Campinas, One of the Largest Brazilian Cities

“…production from lignocellulosic materials [62]. This same characteristic (of this low degradability) was observed for banana waste (76.2%) [57].…”

“…The biomethane production by FFW was similar to that of the inoculum; that is, it exhibited two phases of gas production and followed a gradual path. The result in this work was 381.9 ± 14.5 NmLCH 4 gVS −1 , which approximates the AD process for banana waste (373.3 NmLCH 4 gVS −1 ) [57]. Zhang et al [58] found an inoculum-to-substrate ratio that varied between 445 ± 2 NmLCH 4 gVS −1 and 456 ± 7 NmLCH 4 gVS −1 .…”

“…The low degradability of FFW (74.8%) and GFW (61.3%) is related to the possible recalcitrance of both substrates, which slows the hydrolysis efficiency of the AD process and limits biomethane production from lignocellulosic materials [62]. This same characteristic (of this low degradability) was observed for banana waste (76.2%) [57].…”

Potential Use of Andean Tuber Waste for the Generation of Environmentally Sustainable Bioelectricity

“…The generation of electric current depends on the different mechanics that microbes have for the generation of electrons due to their different forms, and these microbes grow at specific pH values, which is why the standardization of an optimal pH in each MFC is important [27]. Rincon et al (2022) standardized its optimal operating pH at 7.2, using banana waste as substrates in their single-chamber MFC, managing to generate voltage and electric current peaks of 300 mV and 0.2867 mA, attributing the pH value to the state of maturity of the banana used and its components (oxalic, citric, and malic) [28]. Molasses has been used as a substrate in single-chamber MFCs, achieving an optimal pH of 5.25 ± 0.12, and it was shown that the increase in pH value causes the performance of the MFC to decrease due to the variation in the ionization state of the amino and carboxyl functional groups that are present in the bacterial biofilm of the anode electrode [29].…”

Obtaining Sustainable Electrical Energy from Pepper Waste

“…The reduction in the COD confirms that the organic substances were oxidized by the microorganisms present in the substrate and that as the electrons were generated, a continuous decrease in the suspended organic matter occurred [50,51]. Rincón et al (2022) used banana waste as fuel in their MFCs, managing to reduce the COD by 85.4 ± 1.0% due to the degradation of banana waste where they found salts belonging to the stems and green peels; these salts helped the transport of electrons giving stability to the output potential [52]. The reduction in the COD is related to the drop in voltage due to the decrease in the metabolism of microbes [53].…”