Abstract

In the suspension culture, the sharp structure of some nano-metals may destroy the cells and cause metal washout from the system, causing secondary pollution. A novel method of combination of nano-metals addition and immobilized dark fermentation microorganism can overcome this problem. In this study, the co-immobilization approach, nano-metal and the dark-fermented bacteria were incubated together within PVA-boric acid gel granule, could prevent washout of hydrogen producing microorganism as well as the added nano-metals. The results showed when 400 mg/L nano-metal nickel (NP-Ni) and 400 mg/L nano-metal iron (NP-Fe) were added within the immobilized cell, both the maximum H2 production yield (HPY) and H₂production rate (HPR) were improved to be 1.28 mol H₂/mol glucose, 3.13 H₂ L/L/day and 1.19 mol H₂/mol glucose, 1.90 H₂ L/L/day, respectively. The method is expected not only to allow microorganisms to have higher environmental tolerance but also increase hydrogen production.