*4.5. Fruit Waste*

To date, the biodegradation of fruit waste effluent is a challenge due to monosaccharides, disaccharides, and polysaccharides which can facilitate an exponential proliferation of disease-causing organisms when such effluent is release into rivers untreated. As observed indifferent MFCs configurations, a proportion of fruit wastes can generate about 330 mV during conversion, as observed in some biotransformation of effluent from fruit processing (Table 2) [96]. In another study, a voltage of 0.563 V and 0.492 V in MFC was generated when an orange and banana peel effluent was used with no chemical pretreatment. The residual total reducible sugars were a source of carbon for the microbial consortium [97]. Different fruit processing effluent containing residues and soluble components from orange, lemon, grape, and mixed fruit processing were observed for their performance in MFCs to assess the generation of power output compared to conventional MFCs. Improved performance resulting from highly fermentable carbohydrates was observed; albeit, the concentration of organic acids such as citric acid from lemon fruit processing, might have been detrimental for the MFC performance [98]. Lemon processing effluent was considered a source of energy in which the electrogenic population in the dual-chambered MFC led to an electron recovery of 0.99 A/m<sup>2</sup> with 32.3% CE [99]. Therefore, fruit waste and peel extract containing effluent can be considered an alternative source of energy-rich support for electrochemical oxidation in MFCs and possibly can invigorate an emerging renewable energy technology development field.
