scholarly journals Biosynthesis of medium chain length poly-3-hydroxyalkanoates by Pseudomonas guezennei from various carbon sources

2008 ◽  
Vol 68 (11) ◽  
pp. 1534-1541 ◽  
Author(s):  
Christelle Simon-Colin ◽  
Gérard Raguénès ◽  
Bernard Costa ◽  
Jean Guezennec
2018 ◽  
Vol 6 (4) ◽  
Author(s):  
Eduardo L. Almeida ◽  
Lekha M. Margassery ◽  
Niall O’Leary ◽  
Alan D. W. Dobson

ABSTRACTPseudomonas putidastrain CA-3 is an industrial bioreactor isolate capable of synthesizing biodegradable polyhydroxyalkanoate polymers via the metabolism of styrene and other unrelated carbon sources. The pathways involved are subject to regulation by global cellular processes. The draft genome sequence is 6,177,154 bp long and contains 5,608 predicted coding sequences.


2011 ◽  
Vol 78 (2) ◽  
pp. 519-527 ◽  
Author(s):  
Qin Wang ◽  
Ryan C. Tappel ◽  
Chengjun Zhu ◽  
Christopher T. Nomura

ABSTRACTPseudomonas putidaKT2440 is capable of producing medium-chain-length polyhydroxyalkanoates (MCL-PHAs) when grown on unrelated carbon sources during nutrient limitation. Transcription levels of genes putatively involved in PHA biosynthesis were assessed by quantitative real-time PCR (qRT-PCR) inP. putidagrown on glycerol as a sole carbon source. The results showed that two genes,phaGand the PP0763 gene, were highly upregulated among genes potentially involved in the biosynthesis of MCL-PHAs from unrelated carbon sources. Previous studies have describedphaGas a 3-hydroxyacyl-acyl carrier protein (ACP)-coenzyme A (CoA) transferase, and based on homology, the PP0763 gene was predicted to encode a medium-chain-fatty-acid CoA ligase. High expression levels of these genes during PHA production inP. putidaled to the hypothesis that these two genes are involved in PHA biosynthesis from non-fatty acid carbon sources, such as glucose and glycerol. ThephaGppand PP0763 genes fromP. putidawere cloned and coexpressed with the engineeredPseudomonassp. 61-3 PHA synthase genephaCl(STQK)psin recombinantEscherichia coli. Up to 400 mg liter−1MCL-PHAs was successfully produced from glucose. This study has produced the largest amount of MCL-PHAs reported from non-fatty acid carbon sources in recombinantE. colito date and opens up the possibility of using inexpensive feedstocks to produce MCL-PHA polymers.


2008 ◽  
Vol 75 (2) ◽  
pp. 337-344 ◽  
Author(s):  
Daniel J. Koch ◽  
Mike M. Chen ◽  
Jan B. van Beilen ◽  
Frances H. Arnold

ABSTRACT Enzymes of the AlkB and CYP153 families catalyze the first step in the catabolism of medium-chain-length alkanes, selective oxidation of the alkane to the 1-alkanol, and enable their host organisms to utilize alkanes as carbon sources. Small, gaseous alkanes, however, are converted to alkanols by evolutionarily unrelated methane monooxygenases. Propane and butane can be oxidized by CYP enzymes engineered in the laboratory, but these produce predominantly the 2-alkanols. Here we report the in vivo-directed evolution of two medium-chain-length terminal alkane hydroxylases, the integral membrane di-iron enzyme AlkB from Pseudomonas putida GPo1 and the class II-type soluble CYP153A6 from Mycobacterium sp. strain HXN-1500, to enhance their activity on small alkanes. We established a P. putida evolution system that enables selection for terminal alkane hydroxylase activity and used it to select propane- and butane-oxidizing enzymes based on enhanced growth complementation of an adapted P. putida GPo12(pGEc47ΔB) strain. The resulting enzymes exhibited higher rates of 1-butanol production from butane and maintained their preference for terminal hydroxylation. This in vivo evolution system could be useful for directed evolution of enzymes that function efficiently to hydroxylate small alkanes in engineered hosts.


Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2222
Author(s):  
Anuchan Panaksri ◽  
Nuttapol Tanadchangsaeng

Currently, the selection of materials for tissue engineering scaffolds is still limited because some tissues require flexible and compatible materials with human cells. Medium-chain-length polyhydroxyalkanoate (MCL-PHA) synthesized in microorganisms is an interesting polymer for use in this area and has elastomeric properties compatible with the human body. MCL-PHAs are elastomers with biodegradability and cellular compatibility, making them an attractive material for fabricating soft tissue that requires high elasticity. In this research, MCL-PHA was produced by fed-batch fermentation that Pseudomonas Putida ATCC 47054 was cultured to accumulate MCL-PHA by using glycerol and sodium octanoate as carbon sources. The amounts of dry cell density, MCL-PHA product per dry cells, and MCL-PHA productivity were at 15 g/L, 27%, and 0.067 g/L/h, respectively, and the components of MCL-PHA consisting of 3-hydroxydecanoate (3HD) 64.5%, 3-hydroxyoctanoate (3HO) 32.2%, and 3-hydroxyhexanoate (3HHx) 3.3%. The biosynthesized MCL-PHA terpolyester has a relatively low melting temperature, low crystallinity, and high ductility at 52 °C, 15.7%, and 218%, respectively, and considering as elastomeric polyester. The high-resolution scaffold of MCL-PHA terpolyester biomaterial-ink (approximately 0.36 mm porous size) could be printed in a selected condition with a 3D printer, similar to the optimum pore size for cell attachment and proliferation. The rheological characteristic of this MCL-PHA biomaterial-ink exhibits shear-thinning behavior, leading to good shape fidelity. The study results yielded a condition capable of fabricating an elastomer scaffold of the MCL-PHA terpolyester, giving rise to the ideal soft tissue engineering application.


2014 ◽  
Vol 60 (7) ◽  
pp. 461-468 ◽  
Author(s):  
Jilagamazhi Fu ◽  
Umesh Sharma ◽  
Richard Sparling ◽  
Nazim Cicek ◽  
David B. Levin

Medium-chain-length polyhydroxyalkanoate (mcl-PHA) production by Pseudomonas putida LS46 was analyzed in shake-flask-based batch reactions, using pure chemical-grade glycerol (PG), biodiesel-derived “waste” glycerol (WG), and biodiesel-derived “waste” free fatty acids (WFA). Cell growth, substrate consumption, mcl-PHA accumulation within the cells, and the monomer composition of the synthesized biopolymers were monitored. The patterns of mcl-PHA synthesis in P. putida LS46 cells grown on PG and WG were similar but differed from that of cells grown with WFA. Polymer accumulation in glycerol-based cultures was stimulated by nitrogen limitation and plateaued after 48 h in both PG and WG cultures, with a total accumulation of 17.9% cell dry mass and 16.3% cell dry mass, respectively. In contrast, mcl-PHA synthesis was independent of nitrogen concentration in P. putida LS46 cells cultured with WFA, which accumulated to 29% cell dry mass. In all cases, the mcl-PHAs synthesized consisted primarily of 3-hydroxyoctanoate (C8) and 3-hydroxydecanoate (C10). WG and WFA supported similar or greater cell growth and mcl-PHA accumulation than PG under the experimental conditions used. These results suggest that biodiesel by-product streams could be used as low-cost carbon sources for sustainable mcl-PHA production.


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).


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