Triggering photo fermentative biohydrogen production through NiFe2O4 photo nanocatalysts with various excitation sources

The triggering effects of nickel ferrite (NiFe 2 O 4 ) photo nanocatalysts on photo fermentative hydrogen production (PFHP), and metabolic pathways under various excitation sources (incandescent lamp, Xenon lamp, and 532 laser) have been investigated. Compare to the control group (CG) highest cumulative hydrogen volume (CHV) and the maximum hydrogen production rate (HPR) of 568.8 mL and 9.17 mL/h, respectively were achieved at a loading centration of 150 mg/L excited with an incandescent lamp. The change in metabolites with NiFe 2 O 4 incorporation suggests that bacterial activity is significantly affected by photo nanocatalysts. Triggering of NiFe 2 O 4 by laser excitation showed the highest HPR of 7.83 mL /h within 24 h, which greatly reduces the lag time. The microbial community investigation showed that the addition of NiFe 2 O 4 photo nanocatalysts and the change of light source effectively improved the microbial community structure and increased the abundance of hydrogen-producing bacteria (HPB) which leads to enhanced hydrogen production.