초록
<P><B>Abstract</B></P> <P> <I>Escherichia coli</I> wild type has the ability to utilize lactose or the mixture of lactose and glycerol producing bio-hydrogen (H<SUB>2</SUB>) at different pH values. At pH 7.5 in <I>hyaB</I> (lacking large subunit of hydrogenase (Hyd)-1) and <I>hybC</I> (lacking large subunit of Hyd-2) single mutants fermenting lactose (1 g L<SUP>−1</SUP>) H<SUB>2</SUB> yield was ∼7- and 5-fold more, respectively, compared to the wild type. During the fermentation of lactose (1 g L<SUP>−1</SUP>) and glycerol (10 g L<SUP>−1</SUP>) mixture H<SUB>2</SUB> yield in wild type increased ∼3-fold, compared to fermenting lactose only. H<SUB>2</SUB> generation in wild type was monitored in batch cultures during 168 h of growth when utilizing the mixture of lactose and glycerol in all combinations of different concentration. In <I>hyaB</I> but not in <I>hybC</I> mutant H<SUB>2</SUB> evolution was detected till 240 h in the mixture of 5 g L<SUP>−1</SUP> lactose and 10 g L<SUP>−1</SUP> glycerol. The highest H<SUB>2</SUB> production rate of 21.94 mL L<SUP>−1</SUP> h<SUP>−1</SUP> was detected in <I>hyaB</I> mutant at pH 7.5 when 1 g L<SUP>−1</SUP> lactose was applied. The results showed optimized H<SUB>2</SUB> production using different mutants, lactose and its mixture with glycerol. They can be applied for renewable energy, especially bio-H<SUB>2</SUB> production.</P> <P><B>Highlights</B></P> <P> <UL> <LI> H<SUB>2</SUB> production during fermentation of lactose and/or glycerol by <I>E. coli</I> was studied. </LI> <LI> At pH 7.5 in <I>hyaB</I> and <I>hybC</I> mutants high H<SUB>2</SUB> yield was obtained. </LI> <LI> 1 g L<SUP>−1</SUP> lactose, pH 7.5 are optimal conditions for high H<SUB>2</SUB> production rate. </LI> <LI> In <I>hybC</I> mutant H<SUB>2</SUB> evolution was monitored till 240 h. </LI> <LI> <I>hyaB</I> mutant reached H<SUB>2</SUB> production rate of 21.94 ml L<SUP>−1</SUP> h<SUP>−1</SUP> at optimized conditions. </LI> </UL> </P>