• Title/Summary/Keyword: PHA

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Molecular Structure of PCR Cloned PHA Synthase Genes of Pseudomonas putida KT2440 and Its Utilization for Medium-Chain Length Polyhydroxyalkanoate Production

  • Kim, Tae-Kwon;Shin, Hyun-Dong;Seo, Min-Cheol;Lee, Jin-Nam;Lee, Yong-Hyun
    • Journal of Microbiology and Biotechnology
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    • v.13 no.2
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    • pp.182-190
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    • 2003
  • A new phaC gene cluster encoding polyhydroxyalkanoate (PHA) synthase I PHA depolymerase, and PHA synthase II was cloned using the touchdown PCR method, from medium-chain length (mcl-) PHA-producing strain Pseudomonas putida KT2440. The molecular structure of the cloned phaCl gene was analyzed, and the phylogenic relationship was compared with other phaCl genes cloned from Pseudomonas species. The cloned phaCl gene was expressed in a recombinant E. coli to the similar level of PHA synthase in the parent strain P. putida KT2440, but no significant amount of mcl-PHA was accumulated. The isolated phaCl gene was re-introduced into the parent strain P. putida KT2440 to amplify the PHA synthase I activity, and the recombinant P. purida accumulated mcl-PHA more effectively, increasing from 26.6 to $43.5\%$. The monomer compositions of 3-hydroxylalkanoates in mcl-PHA were also modified significantly in the recombinant P. putida enforcing the cloned phaCl gene.

A Novel Nucleic Lateral Flow Assay for Screening phaR-Containing Bacillus spp.

  • Wint, Nay Yee;Han, Khine Kyi;Yamprayoonswat, Wariya;Ruangsuj, Pattarawan;Mangmool, Supachoke;Promptmas, Chamras;Yasawong, Montri
    • Journal of Microbiology and Biotechnology
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    • v.31 no.1
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    • pp.123-129
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    • 2021
  • Polyhydroxyalkanoate (PHA) synthase is a key enzyme for PHA production in microorganisms. The class IV PHA synthase is composed of two subunits: PhaC and PhaR. The PhaR subunit, which encodes the phaR gene, is only present in class IV PHA synthases. Therefore, the phaR gene is used as a biomarker for bacteria that contain a class IV PHA synthase, such as some Bacillus spp. The phaR gene was developed to screen phaR-containing Bacillus spp. The phaR screening method involved two steps: phaR gene amplification by PCR and phaR amplicon detection using a DNA lateral flow assay. The screening method has a high specificity for phaR-containing Bacillus spp. The lowest amount of genomic DNA of B. thuringiensis ATCC 10792 that the phaR screening method could detect was 10 pg. This novel screening method improves the specificity and sensitivity of phaR gene screening and reduces the time and cost of the screening process, which could enhance the opportunity to discover good candidate PHA producers. Nevertheless, the screening method can certainly be used as a tool to screen phaR-containing Bacillus spp. from environmental samples.

Production of Bioplastics from Activated Sludge in a Mixed Culture (혼합배양계에서 활성오니를 이용한 생분해성플라스틱 생산 연구)

  • Cho, Jae-Kyoung
    • Journal of the Korea Organic Resources Recycling Association
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    • v.9 no.3
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    • pp.119-126
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    • 2001
  • A process for the production of bioplastics from wastewater with an open microbial culture was developed and evaluated. The process consists of a selection reactor to select bacteria in feast/famine regime and an accumulation reactor to produce PHA using selected bacteria. Polyhydroxyalkanoate(PHAs) accumulating bacteria could be efficiently grown in a sequencing batch reactor(SBR) without any growth limitation. For the high production of PHA limitation such as oxygen and nutrients seemed to be needed. Accumulation experiments were performed to evaluate the level of accumulation of PHA. Limited aeration had no effect, but nutrients limitation showed high accumulation. Bacteria which were selected in the SBR could accumulate PHA till 60% of cellular dry weight in accumulation experiments under nitrogen limitation. PHA accumulation rate decreased with increasing PHA content in the cells. Clearly, PHA accumulation rate has a strong correlation with the PHA content of the cells.

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Substrate chain-length specificities of polyhydroxyalkanoate synthases PhaC1 and PhaC2 from Pseudomonas aeruginosa P-5 (Pseudomonas aeruginosa P-5에 존재하는 polyhydroxyalkanoate synthase PhaC1과 PhaC2의 기질특이성)

  • Woo, Sang Hee;Lee, Sun Hee;Rhee, Young Ha
    • Korean Journal of Microbiology
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    • v.52 no.4
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    • pp.455-462
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    • 2016
  • Pseudomonas aeruginosa P-5 is an unusual organism capable of synthesizing polyhydroxyalkanoates (PHAs) consisting of 3-hydroxyvalerate (3HV) and medium-chain-length (MCL) 3-hydroxyalkanoate (3HA) monomer units when C-odd alkanoic acids are fed as the sole carbon source. Evaluation of the substrate chain-length specificity of two P. aeruginosa P-5 PHA synthases ($PhaC1_{P-5}$ and $PhaC2_{P-5}$) by heterologous expression of $PhaC1_{P-5}$ and $PhaC2_{P-5}$ genes in Pseudomonas putida GPp104 revealed that $PhaC2_{P-5}$ incorporates both 3HV and MCL 3HAs into PHA, whereas $PhaC1_{P-5}$ favors only MCL 3HAs for polymerization. In order to obtain $PhaC2_{P-5}$ mutants with altered substrate specificity, site-specific mutagenesis for $PhaC2_{P-5}$ was conducted. Amino acid substitutions of $PhaC2_{P-5}$ at two positions (Ser326Thr and Gln482Lys) were very effective for synthesizing copolymers with a higher 3HV fraction. When recombinant P. putida GPp104 harboring double mutated $phaC2_{P-5}$ gene ($phaC2_{P-5}QKST$) was grown on nonanoic acid, 2.5-fold increase of copolymer content with 3.8-fold increase of 3HV fraction was observed. The $phaC2_{P-5}QKST$-containing Ralstonia eutropha PHB-4 supplemented with valeric acid also produced copolymers consisting of 3HV and 3-hydroxyheptanoate with a high 3HV fraction. These results suggest that recombinants containing $phaC2_{P-5}QKST$ could be useful for production of new PHA copolymers with improved material properties.

In Vivo Analysis of fadB Homologous Enzymes Involved in Biosynthesis of Polyhydroxyalkanoates in Recombinant Escherichia coli (재조합 대장균에서 fadB 유사효소의 Polyhydroxyalkanoates 합성에 미치는 역할의 규명)

  • 최종일;박시재;이상엽
    • KSBB Journal
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    • v.19 no.4
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    • pp.331-334
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    • 2004
  • In vivo characterization of FadB homologous enzymes including PaaG, YdbU and YgfG for medium-chain-length (MCL) polyhydroxyalkanoate (PHA) biosynthesis was carried out in fadB mutant Escherichia coli. Previously, it was reported that amplification of FadB homologous enzymes such as PaaG and YdbU in fadB mutant E. coli resulted in enhanced biosynthesis of MCL-PHA by greater than two fold compared with control strain. In this study, we constructed paaG fadB double mutant E. coli WB114 and ydbU fadB double mutant E. coli WB115 to investigate the roles of PaaG and YdbU in biosynthesis of MCL-PHA. Inactivation of paaG and ydbU genes in fadB mutant E. coli harboring Pseudomonas sp. 61-3 phaC2 gene reduced the MCL-PHA production to 0.16 and 0.16 PHA g/L, respectively from 2 g/L of sodium decanoate, which are much lower than 0.43 PHA g/L obtained with fadB mutant E. coli WB101 harboring the phaC2 gene. Also, we identified new FadB homologous enzyme YgfG, and examined its roles by overexpression of ygfG and construction of ygfG fadB double mutant E. coli WB113.

Effect of PHA and conditioned medium on blastogenesis and rosette formation of bovine circulating blood lymphocytes (PHA 및 conditioned medium 이 소의 순환혈액 림프구의 유약화와 rosette 형성에 미치는 영향)

  • Kang, Sei-woong;Yoon, Chang-yong;Song, Hee-jong
    • Korean Journal of Veterinary Research
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    • v.34 no.2
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    • pp.301-306
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    • 1994
  • This study was planned to estimate the activity of bovine circulating blood lymphocytes using phytohemagglutinin-M(PHA) known as T cell mitogen. Bovine circulating blood mononuclear cells(MNCs) was separated, and cultured with or without macrophage($PHA^+/M{\phi}^+$ or $PHA^+/M{\phi}^-$) in conditioned medium which stimulated with various concentration of PHA(0, 5, 10, 15 and $20{\mu}g/ml$ in medium), and then investigated the blastogenic response and rosette formation of lymphocytes. Blastogenic rate(BR) was especially increased in PHA concentration(10 and $15{\mu}g/ml$) of $PHA^+/M{\phi}^+$ group and their BR were $41.5{\pm}6.8%$ and $44.4{\pm}8.9%$, respectively and BR in PHA concentration(15 and $20{\mu}g/ml$) of $PHA^+/M{\phi}^-$ group was $32.8{\pm}6.2%$ and $31.4{\pm}4.6%$, respectively. BR of lymphocytes was more increased in $PHA^+/M{\phi}^+$ than $PHA^+/M{\phi}^-$ group when these cells were stimulated by PHA. Rosette forming rate(RFR) of lymphocytes to SRBC highly increased when SRBC was treated with AET and/or dextran, respectively. On the orther hand, RFR significantly increased more in $PHA^+/M{\phi}^+$ and $PHA^+/M{\phi}^-$ group than in control group, but when compared with two groups, statistical significancy was recognized only in PHA concentration($15{\mu}g/ml$, p<0.026) of $PHA^+/M{\phi}^+$ group.

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Identification and Analysis of Putative Polyhydroxyalkanoate Synthase (PhaC) in Pseudomonas fluorescens

  • Lim, Ju Hyoung;Rhie, Ho-Gun;Kim, Jeong Nam
    • Journal of Microbiology and Biotechnology
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    • v.28 no.7
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    • pp.1133-1140
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    • 2018
  • Pseudomonas fluorescens KLR101 was found to be capable of producing polyhydroxyalkanoate (PHA) using various sugars and fatty acids with carbon numbers ranging from 2 to 6. The PHA granules consisted mainly of a poly(3-hydroxybutyrate) homopolymer and/or poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer. Genomic DNA of P. fluorescens was fractionated and cloned into a lambda library, in which a 5.8-kb fragment that hybridized to a heterologous phaC probe from Ralstonia eutropha was identified. In vivo expression in Klebsiella aerogenes KC2671 (pUMS), restriction mapping, Southern hybridization experiments, and sequencing data revealed that PHA biosynthesis by P. fluorescens relied upon a polypeptide encoded by a 1,683-bp non-operonal ORF, which was preceded by a possible -24/-12 promoter and highly similar to DNA sequences of a gene encoding PHA synthase in the genus Pseudomonas. In vivo expression of the putative PHA synthase gene ($phaC_{Pf}$) in a recombinant Escherichia coli strain was investigated by using glucose and decanoate as substrates. E. coli (${phaC_{Pf}}^+$, pUMS) grown in medium containing glucose accumulated PHA granules consisting mainly of 3-hydroxybutyrate, whereas only a trace amount of 3-hydroxydecanoate was detected from an E. coli fadR mutant (${phaC_{Pf}}^+$) grown in medium containing decanoate. In vitro enzymatic assessment experiments showed that 3-hydroxybutyryl-CoA was efficiently used as a substrate of purified $PhaC_{Pf}$, suggesting that the putative PHA synthase of P. fluorescens utilizes mainly short-chain-length PHA precursors as a substrate.

Preparation and Properties of PAA/PHA/Organoclay Nanocomposite (PAA/PHA/Organoclay 나노복합재료의 제조 및 특성)

  • Yoon, Doo-Soo;Choi, Jae-Kon;Jo, Byung-Wook
    • Polymer(Korea)
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    • v.34 no.4
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    • pp.326-332
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    • 2010
  • Nanocomposite films were prepared by blending poly(amic acid)(PAA), poly(o-hydroxyamide)( PHA) and organically modified montmorillonite (OMMT) that has a layered structure. XRD, SEM and TEM were used to study the morphology of PAA/PHA nanocomposites, and DMA, TGA, UTM, LOI and PCFC techniques were used to characterize the mechanical and thermal properties, and flame retardancy of the nanocomposites. TEM images revealed that OMMT layers were well dispersed in the PAA/PHA matrix and showed exfoliation and intercalation behavior. The addition of 3 wt% OMMT to the PAA/PHA blend increased the initial modulus of PAA/ PHA blend to 3.68 GPa that was ca. 48% higher than that of the control PAA/PHA blend. Above 4 wt%, however, both the initial modulus and the tensile strength were found to decrease, which might be due to the aggregation of OMMT in PAA/PHA matrix. When the OMMT content was below 3 wt%, the thermal stability and flame retardancy of the PAA/PHA nanocomposites increased with increasing OMMT content.

A Research and Application of Polyhydroxyalkanoates in Biosensor Chip (생분해성 고분자, 폴리하이드록시알카노에이트를 이용한 바이오센서 칩 연구와 그 응용)

  • Park, T.J.;Lee, S.Y.
    • KSBB Journal
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    • v.22 no.6
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    • pp.371-377
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    • 2007
  • Polyhydroxyalkanoates (PHAs) are a family of microbial polyesters that can be produced by fermentation from renewable resources. PHAs can be used as completely biodegradable plastics or elastomers. In this paper, novel applications of PHAs in biosensor are described. A general platform technology was developed by using the substrate binding domain (SBD) of PHA depolymerase as a fusion partner to immobilize proteins of interest on PHA surface. It could be shown that the proteins fused to the SBD of PHA depolymerase could be specifically immobilized onto PHA film, PHA microbead, and microcontact printed PHA surface. We review the results obtained for monitoring the specific interaction between the SBO and PHA by using enhanced green fluorescent protein, red fluorescent protein, single chain antibody against hepatitis B virus preS2 surface protein and severe acute respiratory syndrome coronavirus surface antigen as model proteins. Thus, this system can be efficiently used for studying protein-protein and possibly protein-biomolecule interactions for various biotechnological applications.

Pseudohypoaldosteronism Type 1

  • Cheong, Hae Il
    • Journal of Genetic Medicine
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    • v.10 no.2
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    • pp.81-87
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    • 2013
  • Pseudohypoaldosteronism (PHA), a rare syndrome of systemic or renal mineralocorticoid resistance, is clinically characterized by hyperkalemia, metabolic acidosis, and elevated plasma aldosterone levels with either renal salt wasting or hypertension. PHA is a heterogeneous disorder both clinically and genetically and can be divided into three subgroups; PHA type 1 (PHA1), type 2 (PHA2) and type 3 (PHA3). PHA1 and PHA2 are genetic disorders, and PHA3 is a secondary disease of transient mineralocorticoid resistance mostly associated with urinary tract infections and obstructive uropathies. PHA1 includes two different forms with different severity of the disease and phenotype: a systemic type of disease with autosomal recessive inheritance (caused by mutations of the amiloride-sensitive epithelial sodium channel, ENaC) and a renal form with autosomal dominant inheritance (caused by mutations of the mineralocorticoid receptor, MR). In the kidneys, the distal nephron takes charge of the fine regulation of water absorption and ion handling under the control of aldosterone. Two major intracellular actors necessary for the action of aldosterone are the MR and the ENaC. Impairment of the intracellular aldosterone signal transduction pathway results in resistance to the action of mineralocorticoids, which leads to PHA. Herein, ion handling the distal nephron and the clinico-genetic findings of PHA are reviewed with special emphasis on PHA type 1.