초록
The key factors influencing a co-digestion of the oil palm trunk (OPT) hydrolysate with a slaughterhouse wastewater (SHW) to produce hydrogen by Thermoanaerobacterium thermosaccharolyticum KKU19 were investigated. The OPT hydrolysate was obtained by the hydrolysis of OPT by microwave-H<SUB>2</SUB>SO<SUB>4</SUB> method using 1.56% (w/v) H<SUB>2</SUB>SO<SUB>4</SUB> and 7.50 min reaction time at 450 W. The Plackett-Burman method was used to screen the key factors that influenced the hydrogen production potential (P<SUB>s</SUB>). Results indicated that initial cell concentration, tCOD/TN (total COD/total nitrogen) ratio and CuSO<SUB>4</SUB> concentration influenced the P<SUB>s</SUB>. These factors were further optimized using response surface methodology (RSM) with central composite design (CCD). A maximum P<SUB>s</SUB> of 2604 +/- 86 mL H<SUB>2</SUB>/L substrate was achieved at an initial cell concentration of 224 mg dry cell/L, tCOD/TN ratio of 49.87 and CuSO<SUB>4</SUB> concentration of 13.33 mg/L. The main soluble metabolite products were butyric and acetic acids. The P<SUB>s</SUB> obtained when the hydrolysate was supplemented with SHW (2604mL +/- 86 mL H<SUB>2</SUB>/L substrate) was comparable to the P<SUB>s</SUB> obtained when it was supplemented with yeast extract at the same tCOD/TN (2802 +/- 87 mL H<SUB>2</SUB>/L substrate). This result suggests that SHW can be used to replace the costly nitrogen source.