Figure 2
From: Production of biohydrogen by recombinant expression of [NiFe]-hydrogenase 1 in Escherichia coli
Analysis of metabolism related to H 2 production in E. coli BL21. H2 production in vivo was compared between strains under different conditions. (a) Wild-type BL21, (b) recombinant BL21 expressing hydrogenase 1, (c) recombinant BL21 expressing hydrogenase 1 with addition of 10 mM sodium hypophosphite, (d) wild-type BL21 with addition of 10 mM formate, (e) recombinant BL21 expressing hydrogenase 1 with addition of 10 mM formate. Culture was performed at 37°C and 220 rpm in 125 mL serum bottles containing 100 mL M9CA medium with ampicillin (50 μg/mL) and addition of Ni and Fe at final concentration of 30 μM each, with tight capping for H2 measurement in a shaking incubator (seeding and medium preparation were performed in normal aerobic conditions). Serum bottle containing medium was exposed to air for 5 min, and culture performed under micro-aerobic conditions. H2 production by hydrogenase 1 was initiated upon induction with 1 mM IPTG, and measured using GC, as described in Materials and methods. Each value and error bar represents the mean of two independent cultures and standard deviation.