Ethane-dependent synthesis of polyhydroxyalkanoates by the obligate methanotroph Methylocystis parvus OBBP

Abstract

Under conditions of nutrient-limited growth, Type II obligate methanotrophs oxidize C ₁ compounds, such as methane or methanol and accumulate intracellular granules of poly(3-hydroxybutyrate) (P3HB). Here, we report that, under same nutrient-limited conditions, the Type II obligate methanotroph Methylocystis parvus OBBP can use ethane as its sole carbon and energy source for synthesis P3HB granules, accumulating up to 35 ± 4 wt% P3HB. ¹³ C-NMR spectra of the P3HB confirmed incorporation of ¹³ C from [ ¹³ C ₂ ]ethane. Moreover, when valerate was added as a co-substrate with ethane, oxidation of the ethane supported synthesis of the copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV).