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Fig. 5 | Biotechnology for Biofuels

Fig. 5

From: Renewable and tuneable bio-LPG blends derived from amino acids

Fig. 5

Bio-alkane production by Halomonas TQ10 expressing IHKFG462I in plasmid or chromosomally integrated constructs. Cumulative alkane production by the plasmid-borne inducible construct pHT7LIHKFG462I in LB60 medium supplemented with a casamino acids or b valine. Rate of alkane production of Halomonas TQ10 expressing chromosomally integrated c N3T7LIHKFG462I (inducible) or d N3cΔLIHKFG462I (constitutive). Photobioreactor cultivation (400 mL) was performed with medium pH 6.8 containing 0.5 mL/L antifoam and antibiotic (50 μg/mL spectinomycin or 34 μg/mL chloramphenicol for plasmid-borne and constitutive constructs, respectively). The culture was maintained at 30 °C with 60% stirring output with an airflow rate of 1.21 L/min, and ambient room lighting until mid-log phase (4–5 h). Protein expression was induced by 0.1 mM IPTG, where required, and the culture was maintained for 24–240 h with blue light exposure (1656). Culture medium feeding was employed to maintain an optical density of 0.8 and to replenish the carbon source for the chromosomal constructs. Alkane gas production was monitored by automated (a, b) or manual (c, d) headspace sampling using a Micro GC. The effect of amino acid supply on gaseous alkane titres was investigated by performing triplicate fermentations in three different culture media (Additional file 1: Figs. S8–10). Cumulative propane, isobutane and butane titres were calculated from the average production rates per hour in fermentations from freshly transformed Halomonas TQ10 in each media (a, b and Additional file 1: Fig. S11)

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