초록
This work reports on the effect of initial substrate concentration on COD consumption, pH, and H<SUB>2</SUB> production during cassava processing wastewater fermentation by Clostridium acetobutylicum ATCC 824. Five initial COD wastewater concentrations, namely 5.0, 7.5, 10.7, 15.0, and 30.0 g/L, were used. The results showed that higher substrate concentrations (30.0 and 15.0 COD/L) led to lower H<SUB>2</SUB> yield as well as less efficient substrate conversion into H<SUB>2</SUB>. On the other hand, initial COD concentrations of 10.7, 7.5 and 5 g/L furnished 1.34, 1.2 and 2.41 mol H<SUB>2</SUB>/mol glucose, with efficiency of glucose conversion into H<SUB>2</SUB> of 34, 30, and 60% (mol/mol), respectively. These results demonstrate that cassava processing wastewater, a highly polluting effluent, can be successfully employed as substrate for H<SUB>2</SUB> production by C. acetobutylicum at lower COD concentrations.