Dark fermentative hydrogen gas production from molasses using hot spring microflora

Abstract

This study reports hydrogen gas (H2) production from molasses by hot spring microflora in three stages. During the first two stages most convenient temperature, inoculation percentage (INP) ensuring the highest H2 yield and rate were determined using suspended culture. Then, H2 was produced by the same culture immobilized on porous ceramic rings at three different hydraulic retention times. For the suspended culture experiments, the most effective H2 production resulting 202.32 mL H2/g COD was obtained at 37 °C with 10 INP. The highest H2 formation of 534.35 mLH2/d was realized for the biofilm culture at 0.53-day hydraulic retention time and H2 production using hot spring microflora in biofilm form was found to be promising. The pH of the experiments remained stable around 5.5–6.5 without a requirement for pH adjustment during the fermentation. © 2022 Hydrogen Energy Publications LLC