Butane metabolism by butane-grown ‘Pseudomonas butanovora’

The pathway of butane metabolism by butane-grown ‘Pseudomonas butanovora' was determined to be butane → 1-butanol → butyraldehyde → butyrate. Butane was initially oxidized at the terminal carbon to produce 1-butanol. Up to 90% of the butane consumed was accounted for as 1-butanol when cells were incubated in the presence of 5 mM 1-propanol (to block subsequent metabolism of 1-butanol). No production of the subterminal oxidation product, 2-butanol, was detected, even in the presence of 5 mM 2-pentanol (an effective inhibitor of 2-butanol consumption). Ethane, propane and pentane, but not methane, were also oxidized. Butane-grown cells consumed 1-butanol and other terminal alcohols. Secondary alcohols, including 2-butanol, were oxidized to the corresponding ketones. Butyraldehyde was further oxidized to butyrate as demonstrated by blocking butyrate metabolism with 1 mM sodium valerate. Butyrate also accumulated from butane when cells were incubated with 1 mM sodium valerate. The pathway intermediates (butane, 1-butanol, butyraldehyde and butyrate) and 2-butanol stimulated O2 consumption by butane-grown cells. 1-Butanol, butyraldehyde and butyrate supported growth of ‘P. butanovora’, as did 2-butanol and lactate.