Fig 1.
MFC system performance under low and high seasonal production at a canned-pineapple factory.
A, A schematic diagram of a horizontal flow MFC bioreactor featuring key components such as an anode electrode, air-cathode, and external resistance is shown in the upper panel. The wastewater characteristics at low and high seasonal production and an overview of the MFC operation conditions are presented in the lower panel. B, The performance metrics of all MFC reactors (M1L, M2L, M1H, and M2H) as well as their comparative analysis.
Fig 2.
MFC performance evaluation over 300 days: A, COD concentration, B, sulfide concentration, C, sulfate concentration, D, COD removal rate, E, sulfide removal rate, F, sulfate removal rate, G, voltage, and H, oxidation-reduction potential (ORP) values.
Fig 3.
Characteristics of microbial communities in the MFC systems: A, Principal coordinate analysis (PCoA) using the Bray-Curtis dissimilarity. Microbial community profiles of MFC systems at the phylum (B) and genus (C) levels. Venn diagrams comparing anode-attached microbial genera in M1L and M2L (D) and M2L and M2H reactors (E). All microbiome samples in MFC systems were collected from anodes attached at the inlet (A1), middle (A2), and outlet (A3) points of the reactor, pooled suspended samples (S) of M1L, M2L, and M2H reactors, as well as the inoculum sludge (INOC) and anaerobically-treated pineapple wastewater (PWW).
Fig 4.
Proposed metabolic activities based on microbial abundance profiles of each MFC reactor.
M1H has the highest current density (D) followed by M1L (C), M2L (A), and M2H (B). The range and average microbial abundance are reported in parenthesis for M1L, M2L, and M2H, while estimates for M1H are based on its performance. The predominant genera in each group are indicated along with their abundance.
Fig 5.
M1L-specific microbes potentially related to MFC performance.
A, Venn diagram illustrating the distribution of all 29 microbes specific to M1L within both the anode-attached biofilms and reactor. B, The average microbial abundance, current density and sulfide removal rate for anodes and reactors in different systems. C, Association of microbial abundance with current density and sulfide removal at anode (left), and reactor (right) levels.