Application of magnetite supplementation for enhancing biohydrogen production using Gelidium amansii hydrolysate

Acid hydrolysis of biomass generates a high concentration of hydrolysis by-products, which must be removed. Magnetite (Fe3O4) supplementation can reduce the amount of powdered activated carbon (PAC) input required for detoxification by increasing hydrogen productivity and alleviating the inhibitory effects of hydrolysis byproducts. In this study, sugars were extracted by acid hydrolysis of Gelidium amansii, and hydrogen production using this was quantified with the magnetite supplementation. The total sugar concentration of 0.5 % H2SO4 hydrolysate was 24.4 g/L, including 3.7 g/L of glucose, 18.9 g/L galactose, and 1.7 g/L of arabinose, as well as hydrolysis by-products of 0.9 g/L of formic acid, 1.2 g/L of levulinic acid, and 11.4 g/L of 5-hydroxymethylfurfural (5-HMF). Magnetite supplementation at a concentration of 1.3 g/L or less in 5-HMF, the main by-product, increased hydrogen production by an average of 11.4 %. This strategy will optimize future biohydrogen production processes using Gelidium amansii and reduce detoxification costs.