Production of Polyhydroxyalkanoates Copolymers by Recombinant Pseudomonas in Plasmid- and Antibiotic-Free Cultures

2018 ◽  
Vol 28 (5) ◽  
pp. 225-235
Author(s):  
Edmar Ramos Oliveira-Filho ◽  
Linda P. Guamán ◽  
Thatiane Teixeira Mendonça ◽  
Paul F. Long ◽  
Marilda Keico Taciro ◽  
...  

Three different polyhydroxyalkanoate (PHA) synthase genes (<i>Ralstonia eutropha</i> H16, <i>Aeromonas</i> sp. TSM81 or <i>Aeromonas hydrophila</i> ATCC7966 <i>phaC</i>) were introduced into the chromosome of two <i>Pseudomonas</i> strains: a native medium-chain-length 3-polyhydroxyalkanoate (PHA<sub>MCL</sub>) producer (<i>Pseudomonas</i> sp. LFM046) and a UV-induced mutant strain unable to produce PHA (<i>Pseudomonas</i> sp. LFM461). We reported for the first time the insertion of a chromosomal copy of <i>phaC</i> using the transposon system mini-Tn<i>7</i>. Stable antibiotic marker-free and plasmid-free recombinants were obtained. Subsequently, P(3HB-<i>co</i>-3HA<sub>MCL</sub>) was produced by these recombinants using glucose as the sole carbon source, without the need for co-substrates and under antibiotic-free conditions. A recombinant harboring <i>A. hydrophila phaC</i> produced a terpolyester composed of 84.2 mol% of 3-hydroxybutyrate, 6.3 mol% of 3-hydroxyhexanoate, and 9.5 mol% of 3-hydroxydecanoate from only glucose. Hence, we were successful in increasing the industrial potential of <i>Pseudomonas</i> sp. LFM461 strain by producing PHA copolymers containing 3HB and 3HA<sub>MCL</sub> using an unrelated carbon source, for the first time in a plasmid- and antibiotic-free bioprocess.

2022 ◽  
Vol 10 (1) ◽  
pp. 184
Author(s):  
Izumi Orita ◽  
Gento Unno ◽  
Risa Kato ◽  
Toshiaki Fukui

Methylorubrum extorquens AM1 is the attractive platform for the production of value-added products from methanol. We previously demonstrated that M. extorquens equipped with PHA synthase with broad substrate specificity synthesized polyhydroxyalkanoates (PHAs) composed of (R)-3-hydroxybutyrate and small fraction of (R)-3-hydroxyvalerate (3HV) and (R)-3-hydroxyhexanoate (3HHx) units on methanol. This study further engineered M. extorquens for biosynthesis of PHAs with higher 3HV and 3HHx composition focusing on the EMC pathway involved in C1 assimilation. The introduction of ethylmalonyl-CoA decarboxylase, catalyzing a backward reaction in the EMC pathway, aiming to increase intracellular propionyl/butyryl-CoA precursors did not affect PHA composition. Reverse b-oxidation pathway and subsequent (R)-specific hydration of 2-enoyl-CoA were then enhanced by heterologous expression of four genes derived from Ralstonia eutropha for the conversion of propionyl/butyryl-CoAs to the corresponding (R)-3-hydroxyacyl-CoA monomers. The resulting strains produced PHAs with higher 3HV and 3HHx compositions, while the methylotrophic growth was severely impaired. This growth impairment was interestingly restored by the addition of La3+ without a negative impact on PHA biosynthesis, suggesting the activation of the EMC pathway by La3+. The engineered M. extorquens synthesized PHA terpolymer composed of 5.4 mol% 3HV and 0.9% of 3HHx with 41% content from methanol as a sole carbon source in the presence of La3+.


2004 ◽  
Vol 70 (2) ◽  
pp. 999-1007 ◽  
Author(s):  
Christopher T. Nomura ◽  
Kazunori Taguchi ◽  
Seiichi Taguchi ◽  
Yoshiharu Doi

ABSTRACT Polyhydroxyalkanoates (PHAs) can be divided into three main types based on the sizes of the monomers incorporated into the polymer. Short-chain-length (SCL) PHAs consist of monomer units of C3 to C5, medium-chain-length (MCL) PHAs consist of monomer units of C6 to C14, and SCL-MCL PHAs consist of monomers ranging in size from C4 to C14. Although previous studies using recombinant Escherichia coli have shown that either SCL or MCL PHA polymers could be produced from glucose, this study presents the first evidence that an SCL-MCL PHA copolymer can be made from glucose in recombinant E. coli. The 3-ketoacyl-acyl carrier protein synthase III gene (fabH) from E. coli was modified by saturation point mutagenesis at the codon encoding amino acid 87 of the FabH protein sequence, and the resulting plasmids were cotransformed with either the pAPAC plasmid, which harbors the Aeromonas caviae PHA synthase gene (phaC), or the pPPAC plasmid, which harbors the Pseudomonas sp. strain 61-3 PHA synthase gene (phaC1), and the abilities of these strains to accumulate PHA from glucose were assessed. It was found that overexpression of several of the mutant fabH genes enabled recombinant E. coli to induce the production of monomers of C4 to C10 and subsequently to produce unusual PHA copolymers containing SCL and MCL units. The results indicate that the composition of PHA copolymers may be controlled by the monomer-supplying enzyme and further reinforce the idea that fatty acid biosynthesis may be used to supply monomers for PHA production.


2012 ◽  
Vol 78 (15) ◽  
pp. 5375-5383 ◽  
Author(s):  
Nicole Lindenkamp ◽  
Elena Volodina ◽  
Alexander Steinbüchel

ABSTRACTβ-Ketothiolases catalyze the first step of poly(3-hydroxybutyrate) [poly(3HB)] biosynthesis in bacteria by condensation of two acetyl coenzyme A (acetyl-CoA) molecules to acetoacetyl-CoA and also take part in the degradation of fatty acids. During growth on propionate or valerate,Ralstonia eutrophaH16 produces the copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [poly(3HB-co-3HV)]. InR. eutropha, 15 β-ketothiolase homologues exist. The synthesis of 3-hydroxybutyryl-CoA (3HB-CoA) could be significantly reduced in an 8-fold mutant (Lindenkamp et al., Appl. Environ. Microbiol. 76:5373–5382, 2010). In this study, a 9-fold mutant deficient in nine β-ketothiolase gene homologues (phaA,bktB, H16_A1713, H16_B1771, H16_A1528, H16_B0381, H16_B1369, H16_A0170, andpcaF) was generated. In order to examine the polyhydroxyalkanoate production capacity when short- or long-chain and even- or odd-chain-length fatty acids were provided as carbon sources, the growth and storage behavior of several mutants from the previous study and the newly generated 9-fold mutant were analyzed. Propionate, valerate, octanoate, undecanoic acid, or oleate was chosen as the sole carbon source. On octanoate, no significant differences in growth or storage behavior were observed between wild-typeR. eutrophaand the mutants. In contrast, during the growth on oleate of a multiple mutant lackingphaA,bktB, and H16_A0170, diminished poly(3HB) accumulation occurred. Surprisingly, the amount of accumulated poly(3HB) in the multiple mutants grown on gluconate differed; it was much lower than that on oleate. The β-ketothiolase activity toward acetoacetyl-CoA in H16ΔphaAand all the multiple mutants remained 10-fold lower than the activity of the wild type, regardless of which carbon source, oleate or gluconate, was employed. During growth on valerate as a sole carbon source, the 9-fold mutant accumulated almost a poly(3-hydroxyvalerate) [poly(3HV)] homopolyester with 99 mol% 3HV constituents.


2013 ◽  
Vol 79 (12) ◽  
pp. 3582-3589 ◽  
Author(s):  
Daniel Heinrich ◽  
Björn Andreessen ◽  
Mohamed H. Madkour ◽  
Mansour A. Al-Ghamdi ◽  
Ibrahim I. Shabbaj ◽  
...  

ABSTRACTIn recent years, glycerol has become an attractive carbon source for microbial processes, as it accumulates massively as a by-product of biodiesel production, also resulting in a decline of its price. A potential use of glycerol in biotechnology is the synthesis of poly(3-hydroxypropionate) [poly(3HP)], a biopolymer with promising properties which is not synthesized by any known wild-type organism. In this study, the genes for 1,3-propanediol dehydrogenase (dhaT) and aldehyde dehydrogenase (aldD) ofPseudomonas putidaKT2442, propionate-coenzyme A (propionate-CoA) transferase (pct) ofClostridium propionicumX2, and polyhydroxyalkanoate (PHA) synthase (phaC1) ofRalstonia eutrophaH16 were cloned and expressed in the 1,3-propanediol producerShimwellia blattae. In a two-step cultivation process, recombinantS. blattaecells accumulated up to 9.8% ± 0.4% (wt/wt [cell dry weight]) poly(3HP) with glycerol as the sole carbon source. Furthermore, the engineered strain tolerated the application of crude glycerol derived from biodiesel production, yielding a cell density of 4.05 g cell dry weight/liter in a 2-liter fed-batch fermentation process.


1999 ◽  
Vol 65 (8) ◽  
pp. 3561-3565 ◽  
Author(s):  
Dana Kolibachuk ◽  
Andrea Miller ◽  
Douglas Dennis

ABSTRACT The polyhydroxyalkanoic acid synthase gene fromChromobacterium violaceum (phaC Cv) was cloned and characterized. A 6.3-kb BamHI fragment was found to contain both phaC Cv and the polyhydroxyalkanoic acid (PHA)-specific 3-ketothiolase (phaA Cv). Escherichia coli strains harboring this fragment produced significant levels of PHA synthase and 3-ketothiolase, as judged by their activities. While C. violaceum accumulated poly(3-hydroxybutyrate) or poly(3-hydroxybutyrate-co-3-hydroxyvalerate) when grown on a fatty acid carbon source, Klebsiella aerogenes andRalstonia eutropha (formerly Alcaligenes eutrophus), harboring phaC Cv, accumulated the above-mentioned polymers and, additionally, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) when even-chain-length fatty acids were utilized as the carbon source. This finding suggests that the metabolic environments of these organisms are sufficiently different to alter the product range of the C. violaceum PHA synthase. Neither recombinant E. colinor recombinant Pseudomonas putida harboringphaC Cv accumulated significant levels of PHA. Sequence analysis of the phaC Cv product shows homology with several PHA synthases, most notably a 48% identity with that of Alcaligenes latus (GenBank accession no. AAD10274).


2000 ◽  
Vol 66 (5) ◽  
pp. 2117-2124 ◽  
Author(s):  
Silke Fiedler ◽  
Alexander Steinbüchel ◽  
Bernd H. A. Rehm

ABSTRACT Recently, a new metabolic link between fatty acid de novo biosynthesis and biosynthesis of poly(3-hydroxy-alkanoate) consisting of medium-chain-length constituents (C6 to C14) (PHAMCL), catalyzed by the 3-hydroxydecanoyl-[acyl-carrier-protein]:CoA transacylase (PhaG), has been identified in Pseudomonas putida (B. H. A. Rehm, N. Krüger, and A. Steinbüchel, J. Biol. Chem. 273:24044–24051, 1998). To establish this PHA-biosynthetic pathway in a non-PHA-accumulating bacterium, we functionally coexpressedphaC1 (encoding PHA synthase 1) from Pseudomonas aeruginosa and phaG (encoding the transacylase) fromP. putida in Pseudomonas fragi. The recombinant strains of P. fragi were cultivated on gluconate as the sole carbon source, and PHA accumulation to about 14% of the total cellular dry weight was achieved. The respective polyester was isolated, and GPC analysis revealed a weight average molar mass of about 130,000 g mol−1 and a polydispersity of 2.2. The PHA was composed mainly (60 mol%) of 3-hydroxydecanoate. These data strongly suggested that functional expression of phaC1 andphaG established a new pathway for PHAMCLbiosynthesis from nonrelated carbon sources in P. fragi. When fatty acids were used as the carbon source, no PHA accumulation was observed in PHA synthase-expressing P. fragi, whereas application of the β-oxidation inhibitor acrylic acid mediated PHAMCL accumulation. The substrate for the PHA synthase PhaC1 is therefore presumably directly provided through the enzymatic activity of the transacylase PhaG by the conversion of (R)-3-hydroxydecanoyl-ACP to (R)-3-hydroxydecanoyl-CoA when the organism is cultivated on gluconate. Here we demonstrate for the first time the establishment of PHAMCL synthesis from nonrelated carbon sources in a non-PHA-accumulating bacterium, employing fatty acid de novo biosynthesis and the enzymes PhaG (a transacylase) and PhaC1 (a PHA synthase).


2015 ◽  
Vol 51 (15) ◽  
pp. 3235-3238 ◽  
Author(s):  
R. Ganigué ◽  
S. Puig ◽  
P. Batlle-Vilanova ◽  
M. D. Balaguer ◽  
J. Colprim

This work proves for the first time the bioelectrochemical production of butyrate from CO2as a sole carbon source.


Author(s):  
Vivek Kumar Ranjan ◽  
Shriparna Mukherjee ◽  
Subarna Thakur ◽  
Krutika Gupta ◽  
Ranadhir Chakraborty

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1084
Author(s):  
Hye Soo Lee ◽  
Sun Mi Lee ◽  
Sol Lee Park ◽  
Tae-Rim Choi ◽  
Hun-Suk Song ◽  
...  

Polyhydroxyalkanoates (PHAs) are attractive new bioplastics for the replacement of plastics derived from fossil fuels. With their biodegradable properties, they have also recently been applied to the medical field. As poly(3-hydroxybutyrate) produced by wild-type Ralstonia eutropha has limitations with regard to its physical properties, it is advantageous to synthesize co- or terpolymers with medium-chain-length monomers. In this study, tung oil, which has antioxidant activity due to its 80% α-eleostearic acid content, was used as a carbon source and terpolymer P(53 mol% 3-hydroxybytyrate-co-2 mol% 3-hydroxyvalerate-co-45 mol% 3-hydroxyhexanoate) with a high proportion of 3-hydroxyhexanoate was produced in R. eutropha Re2133/pCB81. To avail the benefits of α-eleostearic acid in the tung oil-based medium, we performed partial harvesting of PHA by using a mild water wash to recover PHA and residual tung oil on the PHA film. This resulted in a film coated with residual tung oil, showing antioxidant activity. Here, we report the first application of tung oil as a substrate for PHA production, introducing a high proportion of hydroxyhexanoate monomer into the terpolymer. Additionally, the residual tung oil was used as an antioxidant coating, resulting in the production of bioactive PHA, expanding the applicability to the medical field.


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