초록
A hydrogen producing facultative anaerobic alkaline tolerant novel bacterial strain was isolated from crude oil contaminated soil and identified as Enterobacter cloacae DT-1 based on 16S rRNA gene sequence analysis. DT-1 strain could utilize various carbon sources; glycerol, CMCellulose, glucose and xylose, which demonstrates that DT-1 has potential for hydrogen generation from renewable wastes. Batch fermentative studies were carried out for optimization of pH and Fe<SUP>2+</SUP> concentration. DT-1 could generate hydrogen at wide range of pH (5-10) at 37 <SUP>o</SUP>C. Optimum pH was; 8, at which maximum hydrogen was obtained from glucose (32 mmol/L), when used as substrate in BSH medium containing 5 mg/L Fe<SUP>2+</SUP> ion. Decrease in hydrogen partial pressure by lowering the total pressure in the fermenter head space, enhanced the hydrogen production performance of DT-1 from 32 mmol H<SUB>2</SUB>/L to 42 mmol H<SUB>2</SUB>/L from glucose and from 19 mmol H<SUB>2</SUB>/L to 33 mmol H<SUB>2</SUB>/L from xylose. Hydrogen yield efficiency (HY) of DT-1 from glucose and xylose was 1.4 mol H<SUB>2</SUB>/mol glucose and 2.2 mol H<SUB>2</SUB>/mol xylose, respectively. Scale up of batch fermentative hydrogen production in proto scale (20 L working volume) at regulated pH, enhanced the HY efficiency of DT-1 from 2.2 to 2.8 mol H<SUB>2</SUB>/mol xylose (1.27 fold increase in HY from laboratory scale). 84% of maximum theoretical possible HY efficiency from xylose was achieved by DT-1. Acetate and ethanol were the major metabolites generated during hydrogen production.