초록
<P><B>Abstract</B></P> <P>The effects of overexpressing <I>atpXF</I> genes encoding <I>b</I> <SUB> <I>2</I> </SUB> subunits of F<SUB>0</SUB>F<SUB>1</SUB>-ATPase in <I>Rhodobacter sphaeroides</I> HY01 on ATPase, nitrogenase and photo-fermentative hydrogen production activities were studied. The results showed that the expression levels of <I>atpXF</I> and <I>f</I> <SUB> <I>1</I> </SUB> operon in ZTHBB (<I>F</I> <SUB> <I>0</I> </SUB> <I>P</I> <SUP>+</SUP> <I>atpXF</I> <SUP>+</SUP>) enhanced by 1870% and 40% while its expression levels of <I>f</I> <SUB> <I>0</I> </SUB> operon and <I>nif</I> decreased by 20% and 50% compared with those of ZTH, respectively; and the expression levels of <I>b</I> <SUB> <I>2</I> </SUB> subunits, <I>f</I> <SUB>0</SUB> operon, <I>f</I> <SUB> <I>1</I> </SUB> operon and <I>nif</I> in ZTHCB (<I>pucP</I> <SUP>+</SUP> <I>atpXF</I> <SUP>+</SUP>) enhanced by 370%, 60%, 130% and 160% compared with those of ZTH, respectively. The ATP contents of ZTHBB and ZTHCB increased by 41.5% and 52.8% compared with that of ZTH, and their nitrogenase activities were increased by 30.0% and 41.0% compared with that of ZTH, respectively. When 25 mM acetic acid and 34 mM butyric acid were employed as carbon source and 6 mM <SMALL>L</SMALL>-glutamate was employed as nitrogen source, their hydrogen yields were 7677 ± 176 mL/L (ZTHBB) and 8458 ± 129 mL/L (ZTHCB), which increased by 16.0% and 29.1% compared with that of ZTH, and their maximum hydrogen production rates were 98.0 ± 4.3 mL/(L·h) (ZTHBB) and 100.1 ± 5.1 mL/(L·h) (ZTHCB) under the same conditions, which increased by 14.6% and 17.1% compared with that of ZTH, respectively. The results suggest that overexpressing <I>atpXF</I> could enhance the expression level of F<SUB>0</SUB>F<SUB>1</SUB>-ATPase and hydrogen production performance of purple non-sulfur bacteria.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Overexpressing <I>atpXF</I> of ATPase in <I>Rhodobacter sphaeroides</I> was achieved. </LI> <LI> The expressions of <I>atpXF</I>, <I>f</I> <SUB> <I>0</I> </SUB> <I>/f</I> <SUB> <I>1</I> </SUB> operon and <I>nif</I> enhanced remarkably in ZTHCB. </LI> <LI> Overexpressing <I>atpXF</I> improved ATP content and nitrogenase activity. </LI> <LI> Overexpressing <I>atpXF</I> could enhance hydrogen production in <I>R. sphaeroides</I>. </LI> </UL> </P>