Gas Fermentation-A Flexible Platform for Commercial Scale Production of Low-Carbon-Fuels and Chemicals from Waste and Renewable Feedstocks.

There is an immediate need to drastically reduce the emissions associated with global fossil fuel consumption in order to limit climate change. However, carbon-based materials, chemicals, and transportation fuels are predominantly made from fossil sources and currently there is no alternative source available to adequately displace them. Gas-fermenting microorganisms that fix carbon dioxide (CO2) and carbon monoxide (CO) can break this dependence as they are capable of converting gaseous carbon to fuels and chemicals.

Biosynthesis of poly[(R)-3-hydroxyalkanoate] copolymers with controlled repeating unit compositions and physical properties.

As applications for biodegradable and biologically produced poly[(R)-3-hydroxyalkanoates] (PHAs) grow into more specialized areas, the need to precisely control the repeating unit composition and consequently the physical properties of these polymers has become essential. A previous study reported our development of Escherichia coli LSBJ in order to produce PHA polymers composed of single repeating units ranging from 4 to 12 carbon atoms. This investigation expands the scope of our effort toward controlling the repeating unit composition of a variety of PHA copolymers.

Glycerine and levulinic acid: renewable co-substrates for the fermentative synthesis of short-chain poly(hydroxyalkanoate) biopolymers.

Glycerine (a biodiesel co-product) and levulinic acid (a pulp and paper co-product) were used as co-substrates for the fermentative synthesis of short-chain polyhydroxyalkanoate (sc-PHA) biopolymers with tunable monomer and molecular weight characteristics. Pseudomonas oleovorans NRRL B-14682 utilized glycerine alone to produce poly(3-hydroxybutyrate) (PHB). When levulinic acid was added to the media at shake-flask scale in concentrations ≤0.

Precise control of repeating unit composition in biodegradable poly(3-hydroxyalkanoate) polymers synthesized by Escherichia coli.

The composition of medium-chain-length (MCL) poly(3-hydroxyalkanoate) (PHA) biopolymers is normally an uncontrollable random mixture of repeating units with differing side chain lengths. Attempts to generate MCL PHA homopolymers and control repeating unit composition have been published in native PHA-producing organisms but have limited ranges for the different sizes of repeating units that can be synthesized. In this study, a new Escherichia coli-based system that exhibits control over repeating unit composition for both MCL PHAs and short-chain-length (SCL) PHAs has been developed, covering an unprecedented range of repeating units.

Development of a new strategy for production of medium-chain-length polyhydroxyalkanoates by recombinant Escherichia coli via inexpensive non-fatty acid feedstocks.

Pseudomonas putida KT2440 is capable of producing medium-chain-length polyhydroxyalkanoates (MCL-PHAs) when grown on unrelated carbon sources during nutrient limitation. Transcription levels of genes putatively involved in PHA biosynthesis were assessed by quantitative real-time PCR (qRT-PCR) in P. putida grown on glycerol as a sole carbon source.