Cell growth and accumulation of polyhydroxyalkanoates from CO 2 and H 2 of a hydrogen-oxidizing bacterium, Cupriavidus eutrophus B-10646

Kiselev

et al. 2016

Biotechnology Progress

This study investigates synthesis of poly(3-hydroxybutyrate)/diethylene glycol copolymers (P3HB/DEG) by Cupriavidus eutrophus B-10646 cells as related to DEG concentration in the medium and the time when it is added to the culture of cells synthesizing P3HB. The study determines the limits of physiological effect of DEG on C. eutrophus cells, showing that at DEG concentrations above 30 g/L, it inhibits cell growth, decreasing cell concentration and total P3HB/DEG yield and inducing an increase in the degree of saturation of fatty acids in lipids of cell cytoplasmic membrane. A series of copolymers containing different molar fractions of DEG (between 0.13 and 3.0 mol%) have been synthesized and their physicochemical, physical/mechanical, and biological properties have been investigated as related to the chemical composition and proportions of DEG monomers of the polymers. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1017-1028, 2016.

Section: Methodssupporting

confidence: 91%

A study of synthesis and properties of poly‐3‐hydroxybutyrate/diethylene glycol copolymers

Kiselev

et al. 2016

Biotechnology Progress

“…P(3HB) concentration in cell biomass was not affected by CO concentration; after 56 h of cultivation, it reached 52.6-58.0 % in the experiment with nitrogen deficiency, 60.6-62.8 % under sulfur deficiency, and 58.9-62.7 % under nitrogen and sulfur deficiencies. P(3HB) productivity reached 0.13-0.22 g/L h. That was considerably higher than the P(3HB) productivity achieved in previous studies [30], when the yield of P(3HB) synthesized by S. carboxydohydrogena Z-1062 cells was 27-28 % of the biomass weight, but polymer productivity was no more than 0.1 g/L h. P(3HB) yields were similar to those achieved in studies of CO-resistant strains of hydrogen-oxidizing bacteria Ralstonia eutropha B5786 and Cupriavidus eutrophus 10646 [15,21] and Ideonella sp. O-1 at CO concentrations 5 and 20 % v/v [17].…”

Section: Discussionsupporting

confidence: 79%

“…The Japanese team scaled up P(3HB) synthesis in fermenters with high mass exchange parameters, in the culture of Alcaligenes eutrophus, and achieved cell biomass and polymer content of 91.3 g/L and 61.9 %, respectively [11,14]. The research team at the Institute of Biophysics SB RAS produced P(3HB) and copolymers with different chemical structures in autotrophic cultures of the strains Ralstonia eutropha B5786 and Cupriavidus eutrophus B-10646 [12,15].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of poly(3-hydroxybutyrate) by the autotrophic CO-oxidizing bacterium Seliberia carboxydohydrogena Z-1062

Journal of Industrial Microbiology and Biotechnology

Shishatskaya

2015

The present study addresses growth parameters and physiological and biochemical characteristics of the aerobic CO-oxidizing carboxydobacterium Seliberia carboxydohydrogena Z-1062. Poly(3-hydroxybutyrate) yields were investigated in experiments with limiting concentrations of mineral nutrients (nitrogen or sulfur or nitrogen and sulfur) in batch culture of S. carboxydohydrogena Z-1062 grown on gas mixtures consisting of CO(2), O(2), H(2), and CO. CO concentrations of 10, 20, and 30 % v/v did not affect polymer synthesis, whose content after 56-h cultivation under limiting concentrations of nitrogen and sulfur was 52.6-62.8 % of biomass weight at a productivity of 0.13-0.22 g/L h. The inhibitory effect of CO on cell concentration was revealed at CO concentration of 30 % v/v. That also caused a decrease in substrate (H(2) and O(2)) use efficiency. Thus, this carboxydobacterium can be regarded as a potential producer of polyhydroxyalkanoates from industrial hydrogenous sources.

“…Cell biomass increase was evaluated by periodically measuring culture optical density and determining cell concentration (by weighing the dry matter). Analyses for the determination of optical density and cell dry biomass were carried out following procedures described previously …”

Section: Methodsmentioning

confidence: 99%

Biosynthesis and properties of P(3HB‐co‐3HV‐co‐3H4MV) produced by using the wild‐type strain Cupriavidus eutrophus B‐10646

Меньшикова

J of Chemical Tech & Biotech

et al. 2018

BACKGROUND Polyhydroxyalkanoates (PHA) containing 3‐hydroxy‐4‐methylvalerate (3H4MV) have better processing properties than other PHA types and were not prone to ageing. The main challenge in the production of these polymers is to simultaneously achieve high cell biomass, high polymer content, and high molar fraction of 3H4MV. The aim of this study was to investigate the production of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate‐co‐3‐hydroxy‐4‐methylvalerate) [P(3HB‐co‐3 HV‐co‐3H4MV)] by Cupriavidus eutrophus B‐10646, synthesize polymers with different contents of 3H4MV and investigate their properties. RESULTS It was shown that 4‐methylvalerate (4MV, the precursor substrate) concentration in the culture medium must not be higher than 1 g L−1, and that 4MV must be carefully dosed, with at least 10–12 h intervals between supplementations. A series of polymers with molar fractions of 3H4MV between 2.7 and 11.3 mol% was synthesized. Degrees of crystallinity, molecular weight characteristics, and thermal properties of the polymers have been investigated as dependent on proportions of monomers. CONCLUSION The content of 3H4MV depends on the concentration of 4MV and conditions of carbon nutrition. The molar fraction of 3H4MV had a strong effect on the crystalline to amorphous region ratio. PHA containing 3H4MV specimens synthesized in this study had a degree of crystallinity of below 50%, which remained unchanged for 2.5 years. © 2018 Society of Chemical Industry