초록
The effect of heat-shock treatment to selectively enrich acidogenic, H<SUB>2</SUB> producing consortia was investigated for inoculum preparation and to control the process operation. Long term operation (520 days) in suspended-batch mode bioreactors illustrated relative efficiency and feasibility of heat-shock treated consortia (15.78 mol/kg COD<SUB>R</SUB>) in enhancing H<SUB>2</SUB> production (3.31 mol/kg COD<SUB>R</SUB>) when compared to parent (control) consortia. On the contrary, substrate degradation was higher in the control operation (ξ<SUB>COD,</SUB> 62.86%; substrate degradation rate (SDR), 1.34 kg COD<SUB>R</SUB>/m<SUP>3</SUP>-day) compared to heat-shock operation (ξ<SUB>COD,</SUB> 52.6%; SDR, 1.10 kg COD<SUB>R</SUB>/m<SUP>3</SUP>-day). Heat-shock pretreatment has resulted in a marked fermentation pathway shift towards acetic-butyric acid type production. The microbial diversity illustrated dominance in the Clostridia class after applying heat-shock pretreatment. The redox catalytic currents and Tafel analysis strongly support the conclusion of an improved biocatalyst performance after pretreatment with regards to H<SUB>2</SUB> production.