Microbial production of poly- D- 3-hydroxybutyrate from CO 2

Abstract

This short review covers the biotechnological aspects of the production of poly-D-3-hydroxybutyric acid, P(3HB), from H2, O2 and CO2 by autotrophic culture of the hydrogen-oxidizing bacterium, Ralstonia eutropha. Considering the efficiency of utilization of a gas mixture as substrate, a practical fermentation process using R. eutropha for the mass production of P(3HB) from CO2 should be designed on the basis of a recycled-gas, closed-circuit culture system. Also, maintaining the O2 concentration in a gas phase lower than 6.9% (v/v) is essential to prevent the gas mixture from exploding. Our study, using an explosion-proof fermentation bench plant and a two-stage culture system with a newly designed air-lift fermenter, demonstrated that very high P(3HB) yield and productivity could be obtained while the O2 concentration was maintained below 6.9%. However, a study on the continuous production of P(3HB) from CO2 by chemostat culture of R. eutropha revealed that the productivity and content of P(3HB) in the cells was considerably lower than by fed-batch culture. It is deduced that the use of the hydrogen-oxidizing bacterium, Alcaligenes latus, which accumulates P(3HB) even in the exponential growth phase, will be useful for the effective production of P(3HB) from CO2.

Biomediated production of structurally diverse poly(hydroxyalkanoates) from surplus streams of the animal processing industry

“…As reviewed by Khosravi-Darani et al [113], some microbial specialists can even convert gaseous C1-compounds like methane [114,115] or CO 2 [116] towards PHA. The photosynthetic fixation of CO 2 by phototrophic cyanobacteria to produce PHA is especially attracting more and more attention as demonstrated by the increasing global research activities in this direction [117,118].…”

A Glucose-Utilizing Strain, Cupriavidus euthrophus B-10646: Growth Kinetics, Characterization and Synthesis of Multicomponent PHAs

“…Among promising PHA producers are representatives of the genus Cupriavidus (formerly known as Wautersia, Ralstonia, Alcaligenes, Hydrogenomonas ) [12], which have high growth rates and are able to synthesize PHAs from various substrates [13]–[15]. Cupriavidus species include recombinant and wild-type strains that are capable of synthesizing not only poly-3-hydroxybutyrate, a high-crystallinity and brittle polymer, but also PHA copolymers containing monomer units with carbon chains of different lengths (hydroxybutyrate, hydroxyvalerate, hydroxyhexanoate, etc.)…”

Detection of phase-dependent transcriptomic changes and Rubisco-mediated CO2 fixation into poly (3-hydroxybutyrate) under heterotrophic condition in Ralstonia eutropha H16 based on RNA-seq and gene deletion analyses

“…A number of studies have focused on P(3HB) biosynthesis by R. eutropha H16, particularly regarding the biosynthetic pathways and enzymes, as well as the biogenesis, structure, and mobilization of intracellular P(3HB) granule [2-7]. In this strain, P(3HB) is synthesized from the central intermediate acetyl-CoA through three step reactions catalyzed by β-ketothiolase (PhaA), NADPH-dependent acetoacetyl-CoA reductase (PhaB1), and PHA synthase (PhaC1), the genes of which are clustered in phaC1-A-B1 .…”