A Comparative Study of Hemin and TiO₂ under Fed‑Batch Anaerobic Digestion
Description
Research hypothesis This study tested whether soluble Hemin (Ferriprotoporphyrin IX chloride) and particulate TiO₂ act through distinct catalytic mechanisms during anaerobic digestion of corn ethanol stillage under fed-batch conditions. It was hypothesized that: Hemin, as a soluble homogeneous electron mediator, would enhance extracellular electron transfer and methanogenic activity, especially when combined with laboratory-enriched photosynthetic bacteria (LE-PSB). TiO₂, as a heterogeneous conductive particle, would promote electron exchange at particle interfaces, favor hydrolytic and fermentative populations, and accelerate the conversion of metabolic intermediates. The synergistic combination of Hemin and LE-PSB would improve methane yield, methane-to-TOC conversion coefficient (MCC), coenzyme F₄₂₀, cytochrome c (Cyt-c), electrochemical responses, and microbial community structure compared with the control and single treatments. Data content The dataset was generated from a five-cycle fed-batch anaerobic digestion system treating corn ethanol stillage. The treatments include control, Hemin, TiO₂, and Hemin + LE-PSB. The data contain: Cumulative methane production per cycle and across five cycles, Methane-to-TOC conversion coefficient (MCC), Coenzyme F₄₂₀ content, Cytochrome c (Cyt-c) content, Cyclic voltammetry (CV) responses, Microbial community composition. Data collection Laboratory-scale anaerobic digesters were operated in fed-batch mode for five consecutive cycles using corn ethanol stillage as substrate. Hemin and TiO₂ were added at defined concentrations, while LE-PSB was enriched in the laboratory and co-inoculated in the synergistic treatment. Methane production was monitored by gas chromatography or a gas flow meter. TOC was measured with a TOC analyzer. Coenzyme F₄₂₀ and Cyt-c were quantified spectrophotometrically or by HPLC. Cyclic voltammetry was performed using a potentiostat with a three-electrode system. Microbial community composition was analyzed by high-throughput sequencing of 16S rRNA gene amplicons. Each treatment was generally run in replicate, and data are reported as mean ± standard deviation where applicable. Significant findings The synergistic combination of Hemin and LE-PSB enhanced methanogenic performance. Data interpretation and use These data can be used to: Compare the catalytic effects of soluble Hemin and particulate TiO₂ on anaerobic digestion of corn ethanol stillage. Evaluate the synergistic effect of Hemin and LE-PSB on methane production, MCC, F₄₂₀, Cyt-c, and electrochemical activity and so on.