초록
<P><B>Abstract</B></P> <P>A mutant, JL1601, with a <I>cheR2</I> gene deletion was constructed with <I>Rhodobacter capsulatus</I> JL1 as the wild type strain. The effects of pH, ammonia nitrogen concentration and light intensity on the photo-fermentative hydrogen production performance of JL1601 were studied. Suitable pH range for hydrogen production with the <I>cheR2</I> <SUP> <I>-</I> </SUP> mutant migrated from faintly acid to weak alkaline condition, and <I>R.capsulatus</I> JL1601 (<I>cheR2</I> <SUP>-</SUP>) showed higher NH<SUB>3</SUB> N tolerance. The mutant performed better H<SUB>2</SUB> production performance than the wildtype under the same illumination condition. The maximum H<SUB>2</SUB> yield and rate of <I>R.capsulatus</I> JL1601 (<I>cheR2</I> <SUP>-</SUP>) obtained to be 4406.7 ± 45.9 mL/L and 54.1 ± 1.6 mL/(L·h) with the mixture of acetate and butyrate as the carbon sources, which were increased by 36.3% and 12.3% in comparison to those of wildtype, respectively. Practical experiments using acid-enzymatic pretreated cornstalk as the carbon source indicated that, the maximum hydrogen yields by the mutant JL1601 (<I>cheR2</I> <SUP> <I>-</I> </SUP>) was up to 224.85 ± 5.18 mL-H<SUB>2</SUB>/g-cornstalk, which increased by 171.43% compared with that of wild type strain.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A <I>cheR2-</I>deletion strain <I>Rhodobacter capsulatus</I> JL1601 was constructed. </LI> <LI> Its suitable pH range for H<SUB>2</SUB> production migrated from faintly acid to weak alkaline. </LI> <LI> It showed higher NH<SUB>3</SUB> N tolerance than its parental strain <I>R. capsulatus</I> JL1. </LI> <LI> The H<SUB>2</SUB> yield of JL1601 with cornstalk was about 2.7-fold of that using wildtype. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P> <I>cheR2</I> gene inactivation in <I>R.capsulatus</I> JL1601 reduced the energy (ATP) consumption, and enhanced the photo-fermentative H<SUB>2</SUB> production from acid-cellulase pretreated cornstalk.</P> <P>[DISPLAY OMISSION]</P>