초록
<P><B>Abstract</B></P> <P>Photo-fermentative H<SUB>2</SUB> production by mixed bacteria and pure bacterium <I>Rhodopseudomonas faecalis</I> RLD-53 using single and mixed substrate as carbon source was investigated in batch culture. Experimental results showed that 60 mmol/L acetate was the optimal concentration for mixed bacterial H<SUB>2</SUB> production and maximum cumulative H<SUB>2</SUB> volume was 2468 ± 123 mL H<SUB>2</SUB>/L-culture. It was also found that propionate or butyrate was a key factor for enhancing H<SUB>2</SUB> production in mixed substrate system. Photo-H<SUB>2</SUB> production can be greatly promoted when proper concentration of propionate and butyrate were added into acetate medium as mixed substrate and a higher H<SUB>2</SUB> yield of 2931 ± 146 mL H<SUB>2</SUB>/L-culture was obtained. In addition, it was worth noting that when the strain RLD-53 was added into mixed bacteria with different concentration ratios, H<SUB>2</SUB> yield did not yet increase. Interestingly, H<SUB>2</SUB> production capacity gradually decreased with ratio of strain RLD-53 to mixed bacteria from 8:0 to 4:4, and then gradually increased from 4:4 to 0:8. This implied that the competition relationship between strain RLD-53 and mixed bacteria in substrate utilization strongly influenced their H<SUB>2</SUB> production.</P> <P><B>Highlights</B></P> <P> <UL> <LI> 60 mmol/L acetate was optimal concentration for mixed bacterial H<SUB>2</SUB> production. </LI> <LI> Proper concentration of propionate and butyrate can promote H<SUB>2</SUB> production. </LI> <LI> The strain RLD-53 added into mixed bacteria, an interesting trend was observed. </LI> </UL> </P>