초록
<P>Cellulose utilization by hydrogen producers remains an issue due to the low hydrogen yields reported and the pretreatment of cellulose prior to fermentation requires complex and expensive steps. <I>Clostridium termitidis</I> is able to breakdown cellulose into glucose and produce hydrogen. On the other hand, <I>Clostridium beijerinckii</I> is not able to degrade cellulose but is adept at hydrogen production from glucose; therefore, it was chosen to potentially enhance hydrogen production when co-cultured with <I>C. termitidis</I> on cellulose. In this study, batch fermentation tests were conducted to investigate the direct hydrogen production enhancement of mesophilic cellulolytic bacteria <I>C. termitidis</I> co-cultured with mesophilic hydrogen producer <I>C. beijerinckii</I> on cellulose at 2 g l<SUP>−1</SUP> compared to <I>C. termitidis</I> mono-culture. Microbial kinetics parameters were determined by modeling in MATLAB. The achieved highest hydrogen yield was 1.92 mol hydrogen mol<SUP>−1</SUP> hexose equivalent<SUB>added</SUB> in the co-culture compared to 1.45 mol hydrogen mol<SUP>−1</SUP> hexose equivalent<SUB>added</SUB> in the mono-culture. The maximum hydrogen production rate of 26 ml d<SUP>−1</SUP> was achieved in the co-culture. Co-culture exhibited an overall 32 % enhancement of hydrogen yield based on hexose equivalent added and 15 % more substrate utilization. The main metabolites were acetate, ethanol, lactate, and formate in the mono-culture, with also butyrate in the co-culture. Additionally, the hydrogen yield of <I>C. beijerinckii</I> only in glucose was 2.54 mol hydrogen mol<SUP>−1</SUP> hexose equivalent. This study has proved the viability of co-culture of <I>C. termitidis</I> with <I>C. beijerinckii</I> for hydrogen production directly from a complex substrate like cellulose under mesophilic conditions.</P><P><B>Electronic supplementary material</B></P><P>The online version of this article (doi:10.1186/s13568-016-0256-2) contains supplementary material, which is available to authorized users.</P>