Polyhydroxyalkanoate production and related processes

Abstract

Embodiments of the invention relate generally to processes for the production and processing of polyhydroxyalkanoates (PHA) from carbon sources. In several embodiments, PHAs are produced at high efficiencies from carbon-containing gases through the utilization of a regenerative polymerization system.

Description

RELATED APPLICATIONS[0001]This application is a continuation of co-pending U.S. patent application Ser. No. 13 / 392,502 filed Feb. 24, 2012, which is the U.S. National Phase of International Application No. PCT / US2010 / 047052, filed Aug. 27, 2010, which claims the benefit of U.S. Provisional Application Nos. 61 / 237,606, 61 / 237,609, 61 / 237,635, 61 / 237,603, 61 / 237,616, 61 / 237,615, 61 / 237,620, 61 / 237,643, 61 / 237,633, 61 / 237,630, 61 / 237,626, 61 / 237,642, 61 / 237,639, and 61 / 237,627, all filed on Aug. 27, 2009, the entire disclosure of each application in the priority chain is incorporated by reference herein.BACKGROUND[0002]1. Field of the Invention[0003]Embodiments of the invention relate to an improved process for the production and processing of polyhydroxyalkanoates, and specifically to a process for the production of polyhydroxyalkanoates from carbon-containing gases.[0004]2. Description of the Related Art[0005]Polyhydroxyalkanoates (PHAs) are thermoplastic polyesters that serve as ene...

AI Technical Summary

Benefits of technology

This process significantly improves energy, carbon, and chemical efficiencies, enabling the production of PHA at costs competitive with food crop-based and fossil fuel-based plastics by achieving higher cell densities and PHA concentrations, thereby reducing the energy-to-PHA output ratio and increasing carbon input-to-PHA yield.

Problems solved by technology

Unfortunately, despite these maximized efficiency advantages, sugar-based PHA production remains many times more expensive than fossil fuel-based plastics production.

Thus, given the apparent efficiency maximization of the high density sugar-derived PHA production process, PHAs are widely considered to be fundamentally unable to compete with fossil fuel-based plastics on energy, chemical, and cost efficiency.

Despite the environmental advantages of PHAs, the high cost of PHA production relative to the low cost of fossil fuel-based plastics production has significantly limited the industrial production and commercial adoption of PHAs.

Unfortunately, the fermentation of carbon-containing gases presents technical challenges and stoichiometric limitations that have, in the past, rendered the gas-to-PHA production process significantly more energy and chemical intensive, and thus more costly, than the food crop-based PHA production process.

Specifically, these technical challenges and stoichiometric limitations include: low mass transfer rates, low microorganism growth rates, extended polymerization times, low cell densities, high oxygen demand, and low PHA cellular inclusion concentrations.

As a result, the ratio of energy-to-PHA required to carry out upstream carbon injection, optional oxygen injection, and culture mixing, as well as downstream PHA purification, significantly exceeds the energy-to-PHA ratio required for sugar-based PHA production methods, thereby rendering the emissions-based process uncompetitive when compared to both petroleum-based plastics and sugar-based PHAs.

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