초록
The combination of dark- and photo-fermentative bacteria is quite a new approach in hydrogen (H<SUB>2</SUB>) production biotechnology, which offers potential efficient production of H<SUB>2</SUB> from renewable resources. This study is focused on the attempt to obtain high H<SUB>2</SUB> yield by pure and mixed cultures of dark-fermentative (Escherichia coli) and photo-fermentative (Rhodobacter sphaeroides) bacteria using distillers grains (DG), the ethanol fermentation waste. During the growth in diluted DG media H<SUB>2</SUB> production by pure and mixed cultures started at 24 h growth. Moreover, the mixed culture produced significantly more H<SUB>2</SUB> from DG: 2-folds diluted media provided the ~1.5-3-folds higher H<SUB>2</SUB> yield in comparison with pure culture. These effects were obtained for continuous H<SUB>2</SUB> production at 72-96 h growth. DG dilution and neutralization to pH 7.0 were required. The results indicated that DG can be used as effective and valuable source of organic substances in H<SUB>2</SUB> production by bacteria. This study can provide novel approach for an inexpensive energy generation, as well as to resolve the problem of waste utilization.