초록
<P><B>Abstract</B></P><P>This study used a DNA recombination method to knock out the poly-β-hydroxybutyrate (PHB) synthesis gene <I>phbC</I> in the photosynthetic bacterium <I>Rhodopseudomonas palustris</I> WP3-5. The experimental results indicated that the mutant strain <I>Rps. palustris</I> M23 could be successfully screened. Fluorescent observation with Nile blue staining showed no significant PHB granule accumulation in the mutant cells. Batch mode experiments using acetic acid as a carbon source revealed a 29.1% and 25.9% hydrogen gas content from M23 and WP3-5, respectively. However, this trend did not appear when using propionic acid as carbon source. Under continuous operation, the hydrogen gas content from M23 could be maintained above 72%. The average hydrogen production rates of the WP3-5 and M23 strains were 264mL-H<SUB>2</SUB>/L/day and 457mL-H<SUB>2</SUB>/L/day, respectively. The total biogas volume collected from M23 was 1.7 times higher than that from the wild type.</P>