Enhancement effect of defoamer additives on photo-fermentation biohydrogen production process

Foaming is a key issue should be solved in the process of photo-fermentation biohydrogen production (PFHP), since it has negative influence on the hydrogen yield potential, especially when taken straw as substrate. Appropriate foam control measures must be considered for industrialization. Hence, in this work, foam height and biohydrogen yield were selected as index, the effect of defoamer addition on PFHP was investigated. The defoamer has no negative effect on bacterial growth. In the addition range of 0-1 mL/L, the higher addition amount, indicates better foam control effect. The maximum foam height could be reduced by 55% and the foam existence time by 36 h. The reduction of foam was beneficial to biohydrogen production, and the highest cumulative hydrogen yield was increased 23% at the addition level of 0.125 mL/L.