**1. Introduction**

Today, several challenges are besieging the environment, and as such, an equal measure to address such challenges must be in place to counter environmental and ecological degradation [1]. For example, in maintaining a clean and safe environment, waste reduction and recovery of valuable products [2] and/or their repurposing is a must [3]. Nutrient-rich agro-waste is usually produced from agro-processing industries [4]. Similarly, one of the major wastes is agro-based wastewater containing many carbon-based compounds [5], which in turn affects the receiving water bodies when released untreated [5]. Agricultural residues are also considered one of the most prominent substrates in energy and

**Citation:** Pandit, S.; Savla, N.; Sonawane, J.M.; Sani, A.M.; Gupta, P.K.; Mathuriya, A.S.; Rai, A.K.; Jadhav, D.A.; Jung, S.P.; Prasad, R. Agricultural Waste and Wastewater as Feedstock for Bioelectricity Generation Using Microbial Fuel Cells: Recent Advances. *Fermentation* **2021**, *7*, 169. https://doi.org/10.3390/ fermentation7030169

Academic Editors: Giuseppa Di Bella and Alessia Tropea

Received: 25 June 2021 Accepted: 19 August 2021 Published: 28 August 2021

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carbon source content. Their sugars are obtained either via treatment with dilute acids or enzymes [6].

An example of an important agricultural residue is wheat straw containing about 34–40% cellulose organic carbon content, hemicellulose containing about 21–26% of organic carbon, and lignin-containing about 11–23% of organic carbon. All of these can undergo hydrolysis yielding wheat straw hydrolysate, generating a substantial amount of electricity in a microbial fuel cell (MFC) [7]. Similarly, raw corn stover is another important agricultural waste that contributes immensely to the production of electricity when a single-chamber MFC is used. However, the treatment thereof was effective, but the power output was much lower compared to MFC in which glucose is used as a substrate [8].

Agricultural waste, even in agro-industrial wastewater, is produced during agriculture produce pre-harvesting, harvesting, and processing activities. Agricultural processing activities and industrial food processing operations contribute to agro/food-waste and wastewater generation. Agricultural waste can easily undergo biodegradation as it contains a high level of organic matter and many other different macro-and micro-nutrients suitable for microbial growth. Many agro-industrial wastewaters also contain a high concentration of organic pollutants, including a large amount of waste effluent produced from livestock and agro-products processing [9]. However, these agricultural residues and wastewater can be considered new alternative sources of renewable energy that can be converted into biofuels, biogas, bioelectricity, bio-bricks, fertilizer, and biochar [9] suitable technology such as MFCs, among others.
