초록
<P><B>Abstract</B></P> <P>In this paper, the effect of hydraulic retention time (HRT, 16 h–4 h) on fermentative hydrogen production by mixed cultures was firstly investigated in a sucrose-fed anaerobic continuous stirred tank reactor (CSTR) at 35 °C and initial pH 8.79. After stable operations at HRT of 16–6 h, the bioreactor became unstable when the HRT was lowered to 4 h. The maximum hydrogen yield reached 3.28 mol H<SUB>2</SUB>/mol-Sucrose at HRT 4 h. Supplementation of Cu<SUP>2+</SUP> at HRT 4 h improved the operation stability through enhancement of substrate degradation efficiency. The effect of Cu<SUP>2+</SUP> concentration ranging from 1.28 to 102.4 mg/L on fermentative hydrogen production was studied. The results showed that Cu<SUP>2+</SUP> was able to enhance the hydrogen production yield with increasing Cu<SUP>2+</SUP> concentration from 1.28 to 6.4 mg/L. The maximum hydrogen yield of 3.31 mol H<SUB>2</SUB>/mol-Sucrose and the maximum hydrogen production rate of 14.44 L H<SUB>2</SUB>/Day/L-Reactor were obtained at 6.4 mg/L Cu<SUP>2+</SUP> and HRT 4 h Cu<SUP>2+</SUP> at much higher concentration could inhibit the hydrogen production, but it could increase substrate degradation efficiency (12.8 and 25.6 mg/L Cu<SUP>2+</SUP>). The concentration of Cu<SUP>2+</SUP> had effect on the distribution of soluble metabolite.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The effect of Cu<SUP>2+</SUP> concentration on biohydrogen production was examined. </LI> <LI> The concentration of Cu<SUP>2+</SUP> had effect on the distribution of soluble metabolite. </LI> <LI> 6.4 mg/L Cu<SUP>2+</SUP> is the optimum concentration for the CSTR at HRT 4 h. </LI> </UL> </P>