Mono- and co-substrate utilization kinetics using mono- and co-culture of Clostridium beijerinckii and Clostridium saccharoperbutylacetonicum

The effect of co-culturing C. beijerinckii and C. saccharoperbutylacetonicum for H2 production using mono- and co-substrates of glucose, starch, and cellulose was assessed. Monod kinetic parameters (K, maximum specific substrate utilization rate; and Ks, half-saturation constant) of the C. beijerinckii, C. saccharoperbutylacetonicum, and the co-culture were determined. Co-cultures utilizing glucose competed for the substrate, but showed enhancement for utilizing starch. The maximum values for K on glucose and starch were 0.48 g substrate/gVSS.h achieved by C. saccharoperbutylacetonicum mono-culture and 0.39 g substrate/gVSS.h achieved by the co-culture, respectively. The average Ks for all mono- and co-culture experiments was 0.93 ± 0.03 g/L. Acetate, butyrate, and propionate were the main fermentation products for all experiments. Maximum H2 production yields on glucose (2.69 mol/molglucose) and starch (1.07 mol/molhexose) were achieved by C. beijerinckii and C. saccharoperbutylacetonicum mono-cultures, respectively; however, neither culture was able to degrade cellulose as a mono-substrate.