Use of poly(ethylene glycol) to control the end group structure and molecular weight of poly(3-hydroxybutyrate) formed by Alcaligenes latus DSM 1122

Ashby, Richard D.; Shi, Fengying; Gross, Richard A.

doi:10.1016/s0040-4020(97)00958-7

Cited by 38 publications

(65 citation statements)

References 16 publications

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“…This was partly a consequence of their influence on cell mass (Shi et al 1996b). Similar studies using A. latus have shown that PEGs with molecular weights between 106 and 600 had a greater impact on polymer synthesis compared to their higher molecular weight counterparts (1,000 -10,000), with PHB productivity also being reduced depending on PEG concentration in the cultivation medium (Ashby et al 1997). Thus, while 5% (w/v) PEG-106 in the growth media resulted in no PHA synthesis, 10% (w/v) of PEG-10,000 still showed some biopolymer synthesis, although the impact was greater than that observed when the studies were conducted with R. eutropha (Ashby et al 1997).…”

Section: Influence Of Pegs On Pha Bioprocessing Parametersmentioning

confidence: 84%

PEGylation and BioPEGylation of Polyhydroxyalkanoates: Synthesis, Characterisation and Applications

Foster¹

2010

Biopolymers

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Section: Influence Of Pegs On Pha Bioprocessing Parametersmentioning

confidence: 84%

PEGylation and BioPEGylation of Polyhydroxyalkanoates: Synthesis, Characterisation and Applications

Foster¹

2010

Biopolymers

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“…Previous research also showed poly(ethylene glycol) (PEG) could end cap P(3HB). 103,104 In a word, addition of chain termination agents, such as glycerol, PEG, and methanol, results in the production of P(3HB) polymers with lower molecular mass during biosynthesis, and thus, needs to be taken into account for PHA production when using waste glycerol as a carbon source in fermentation process.…”

Section: Production and Characterization Of Polyhydrox-yalkanoates Frmentioning

confidence: 99%

Bioplastics from waste glycerol derived from biodiesel industry

Zhu

Chiu

Nakas

et al. 2013

J of Applied Polymer Sci

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Polyhydroxyalkanoates (PHAs) are polyesters that can be biologically synthesized by many microorganisms and engineered plants that have been investigated by microbiologists, biochemists, polymer scientists, material engineers, and medical researchers for several decades. Research on microbial production of PHAs has been extensively focused on using pure carbon sources, such as sugars and fatty acids. Practical considerations of production costs of PHAs have resulted in research efforts to use alternative renewable and inexpensive feedstocks. One potential feedstock for the production of PHA polymers is the glycerol waste byproduct of biodiesel production. The major focus of this review is the production of PHA polymers from glycerol. A review of biosynthetic pathways for PHAs production from glycerol, current production of waste glycerol in biodiesel industry, physical and mechanical properties of PHAs, and applications of PHAs in the areas of packaging industry, implant materials, drug carrier, biofuels, are covered.

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“…Hence, rational methods for PHA molecular weight control other than our investigations into the use of polyethylene glycol (PEG) in culture media (Shi et al, 1996b;Ashby et al, 1997) have not been reported. However, the variation of PHA molecular weights remains of considerable interest.…”

Section: Introductionmentioning

confidence: 99%

“…The extent of molecular weight reduction depended on the PEG molecular weight and concentration in the incubation medium (Shi et al, 1996b;Ashby et al, 1997). This technology has resulted in the biosynthesis of PHBs with molecular weights (M n ) ranging from 1.1 × 10 4 to 1.2 × 10 6 g/mol.…”

Section: Introductionmentioning

confidence: 99%

“…This technology has resulted in the biosynthesis of PHBs with molecular weights (M n ) ranging from 1.1 × 10 4 to 1.2 × 10 6 g/mol. In one report, control of the PHB molecular weight occurred due to the termination of propagating PHB chains by PEG (Ashby et al, 1997). This resulted in the in vivo formation of PHB-PEG diblock copolymers (natural-synthetic hybrids) by A. latus.…”

Section: Introductionmentioning

confidence: 99%

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A tunable switch to regulate the synthesis of low and high molecular weight microbial polyesters

Ashby

Shi

Gross

1999

Biotechnol. Bioeng.

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The addition of poly(ethylene glycol) (M n = 200 g/mol) to the fermentation media of Alcaligenes eutrophus and Alcaligenes latus at various stages of growth resulted in the synthesis of poly(3hydroxybutyrate) (PHB) with bimodal molecular weight distributions. The presence of 2% w/v-PEG-200 did not have deleterious effects on PHB volumetric yields and cell productivity. In general, the M n values of the high (H) and low (L) fractions showed little variability as a function of the time at which PEG-200 was added to the cultures. By this approach, the H:L ratios (w/w) of the PHB synthesized by A. eutrophus and A. latus were varied from 9:91 to 76:24 and from 16:84 to 88:12, respectively. It is believed that the H fractions were formed prior to the addition of PEG-200 to the cultures. Also, once PEG-200 was made available to the cells, PEG-200 acted as a switch so that the reduced molecular weight fraction was formed. In addition, a necessary requirement for the above is that the frequency of transesterification reactions during polymer synthesis was small. The efficiency that PEG-200 reduced the molecular weight of the PHBs formed by both bacteria appears similar. Indirect evidence suggests that the PHB L fractions formed by A. latus subsequent to PEG-200 addition consist primarily of chains that have PEG terminal groups. This terminal chain structure was not observed for PHB formed by A. eutrophus.

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Use of poly(ethylene glycol) to control the end group structure and molecular weight of poly(3-hydroxybutyrate) formed by Alcaligenes latus DSM 1122

Cited by 38 publications

References 16 publications

PEGylation and BioPEGylation of Polyhydroxyalkanoates: Synthesis, Characterisation and Applications

PEGylation and BioPEGylation of Polyhydroxyalkanoates: Synthesis, Characterisation and Applications

Bioplastics from waste glycerol derived from biodiesel industry

A tunable switch to regulate the synthesis of low and high molecular weight microbial polyesters

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