Displaying publications 1 - 20 of 82 in total

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  1. Polyhydroxybutyrate production from oil palm empty fruit bunch using Bacillus megaterium R11
    Zhang Y, Sun W, Wang H, Geng A
    Bioresour Technol, 2013 Nov;147:307-314.
    PMID: 24001560 DOI: 10.1016/j.biortech.2013.08.029
    Oil palm empty fruit bunch (OPEFB), contains abundant cellulose and hemicelluloses and can be used as a renewable resource for fuel and chemical production. This study, as the first attempt, aims to convert OPEFB derived sugars to polyhydroxybutyrate (PHB). OPEFB collected from a Malaysia palm oil refinery plant was chemically pretreated and enzymatically hydrolyzed by an in-house prepared cellulase cocktail. The PHB producer, Bacillus megaterium R11, was isolated in Singapore and could accumulate PHB up to 51.3% of its cell dry weight (CDW) from both glucose and xylose. Tryptone was identified as its best nitrogen source. PHB content and production reached 58.5% and 9.32 g/L, respectively, for an overall OPEFB sugar concentration of 45 g/L. These respectively reached 51.6% and 12.48 g/L for OPEFB hydrolysate containing 60 g/L sugar with a productivity of 0.260 g/L/h.
    Matched MeSH terms: Polyhydroxyalkanoates/metabolism*
  2. High cell density culture of Cupriavidus necator H16 and improved biological recovery of polyhydroxyalkanoates using mealworms
    Zainab-L I, Sudesh K
    J Biotechnol, 2019 Nov 10;305:35-42.
    PMID: 31493421 DOI: 10.1016/j.jbiotec.2019.09.001
    The cost of polyhydroxyalkanoates (PHAs) can be reduced by improving their productivity and recovery. In this study, we attempted to obtain a high cell density culture from a 13 L bioreactor and subsequently improved the recently developed biological recovery process using mealworms to obtain the PHA granules. A cell dry weight of 161 g/L containing 68-70 wt% P(3HB) was obtained. The freeze-dried cells contained a significant amount of mineral salts from the culture medium which reduced the cells' palatability for the mealworms. A simple washing procedure with water was sufficient to remove the residual mineral salts and this improved the cells' consumption by up to 12.5% of the mealworms' body weight. As a result, one kilogram of mealworms consumed 125 g of the washed cells daily and 87.2 g of feacal pellets were recovered, which was almost twice the weight of the unwashed cells. In addition, it also improved the purity of the PHA in the faecal pellets to a value <90% upon washing with water to remove the water-soluble compounds. This study has demonstrated a significant improvement in the production and recovery of PHA. In addition, the resulting mealworms showed a significant increase in protein content up to 79% and a decrease in fat content down to 8.3% of its dry weight.
    Matched MeSH terms: Polyhydroxyalkanoates/biosynthesis*
  3. Complete Genome Sequence of a Novel Polyhydroxyalkanoate (PHA) Producer, Jeongeupia sp. USM3 (JCM 19920) and Characterization of Its PHA Synthases
    Zain NA, Ng LM, Foong CP, Tai YT, Nanthini J, Sudesh K
    Curr Microbiol, 2020 Mar;77(3):500-508.
    PMID: 31893298 DOI: 10.1007/s00284-019-01852-z
    A novel polyhydroxyalkanoate (PHA)-producing bacterium, Jeongeupia sp. USM3 (JCM 19920) was isolated from the limestone soil at Gua Tempurung, Perak, Malaysia. This is the first report on the complete genome sequence for the genus Jeongeupia. This genome consists of a circular chromosome with a size of 3,788,814 bp and contains 3557 genes. Two PHA synthase (phaC) genes encoding for the key enzyme in the polymerization of PHA monomers and other PHA-associated genes were identified from the genome. Phylogenetic analysis of the PhaC protein sequences has revealed that both PhaC1 and PhaC2 of Jeongeupia sp. USM3 are categorized as Class I PHA synthases with 56% similarity to each other. Both of the PHA synthase genes of this isolate were cloned and heterologously expressed in a PHA mutant strain Cupriavidus necator PHB-4. The ability of the transformants to accumulate PHA showed that both PhaC1 and PhaC2 were functional.
    Matched MeSH terms: Polyhydroxyalkanoates/biosynthesis*
  4. Biosynthesis and characterization of polyhydroxyalkanoate containing high 3-hydroxyhexanoate monomer fraction from crude palm kernel oil by recombinant Cupriavidus necator
    Wong YM, Brigham CJ, Rha C, Sinskey AJ, Sudesh K
    Bioresour Technol, 2012 Oct;121:320-7.
    PMID: 22858502 DOI: 10.1016/j.biortech.2012.07.015
    The potential of plant oils as sole carbon sources for production of P(3HB-co-3HHx) copolymer containing a high 3HHx monomer fraction using the recombinant Cupriavidus necator strain Re2160/pCB113 has been investigated. Various types and concentrations of plant oils were evaluated for efficient conversion of P(3HB-co-3HHx) copolymer. Crude palm kernel oil (CPKO) at a concentration of 2.5 g/L was found to be most suitable for production of copolymer with a 3HHx content of approximately 70 mol%. The time profile of these cells was also examined in order to study the trend of 3HHx monomer incorporation, PHA production and PHA synthase activity. (1)H NMR and (13)C NMR analyses confirmed the presence of P(3HB-co-3HHx) copolymer containing a high 3HHx monomer fraction, in which monomers were not randomly distributed. The results of various characterization analyses revealed that the copolymers containing a high 3HHx monomer fraction demonstrated soft and flexible mechanical properties.
    Matched MeSH terms: Polyhydroxyalkanoates/biosynthesis*; Polyhydroxyalkanoates/chemistry
  5. Complete genome sequence of Aquitalea pelogenes USM4 (JCM19919), a polyhydroxyalkanoate producer
    Wan JH, Ng LM, Neoh SZ, Kajitani R, Itoh T, Kajiwara S, et al.
    Arch Microbiol, 2023 Jan 16;205(2):66.
    PMID: 36645481 DOI: 10.1007/s00203-023-03406-1
    Polyhydroxyalkanoate (PHA) is a type of biopolymer produced by most bacteria and archaea, resembling thermoplastic with biodegradability and biocompatibility features. Here, we report the complete genome of a PHA producer, Aquitalea sp. USM4, isolated from Perak, Malaysia. This bacterium possessed a 4.2 Mb circular chromosome and a 54,370 bp plasmid. A total of 4067 predicted protein-coding sequences, 87 tRNA genes, and 25 rRNA operons were identified using PGAP. Based on ANI and dDDH analysis, the Aquitalea sp. USM4 is highly similar to Aquitalea pelogenes. We also identified genes, including acetyl-CoA (phaA), acetoacetyl-CoA (phaB), PHA synthase (phaC), enoyl-CoA hydratase (phaJ), and phasin (phaP), which play an important role in PHA production in Aquitalea sp. USM4. The heterologous expression of phaC1 from Aquitalea sp. USM4 in Cupriavidus necator PHB-4 was able to incorporate six different types of PHA monomers, which are 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), 4-hydroxybutyrate (4HB), 5-hydroxyvalerate (5HV), 3-hydroxyhexanoate (3HHx) and isocaproic acid (3H4MV) with suitable precursor substrates. This is the first complete genome sequence of the genus Aquitalea among the 22 genome sequences from 4 Aquitalea species listed in the GOLD database, which provides an insight into its genome evolution and molecular machinery responsible for PHA biosynthesis.
    Matched MeSH terms: Polyhydroxyalkanoates*
  6. Effect of famine-phase reduced aeration on polyhydroxyalkanoate accumulation in aerobic granules
    Vjayan T, Vadivelu VM
    Bioresour Technol, 2017 Dec;245(Pt A):970-976.
    PMID: 28946198 DOI: 10.1016/j.biortech.2017.09.038
    The effects of variable aeration in the famine period on polyhydroxyalkanoate (PHA) accumulation in aerobic granules were investigated. Results showed that regardless of the aeration rates used during famine period, all aerobic granules achieved a similar chemical oxygen demand removal and PHA content. The decrease in famine-period aeration rates accelerated the maximum PHA accumulation together with increase in granular size and settling ability. The PHA-accumulating microorganisms were found to have shifted closer to the surface of the granules when the aeration rate was reduced. Moreover, PHA compositional changes occurred, where the hydroxyvalerate content had increased with the reduction in aeration rate. Ultimately, the results indicate that the requirement of aeration for PHA accumulation in aerobic granules is highly insignificant in the famine phase. PHA production in aerobic granules under zero aeration in the famine period may result in an energy input reduction of up to 74%.
    Matched MeSH terms: Polyhydroxyalkanoates
  7. Utilization of waste fish oil and glycerol as carbon sources for polyhydroxyalkanoate production by Salinivibrio sp. M318
    Van Thuoc D, My DN, Loan TT, Sudesh K
    Int J Biol Macromol, 2019 Dec 01;141:885-892.
    PMID: 31513855 DOI: 10.1016/j.ijbiomac.2019.09.063
    A moderately halophilic bacterium isolated from fermenting shrimp paste, Salinivibrio sp. M318 was found capable of using fish sauce and mixtures of waste fish oil and glycerol as nitrogen and carbon sources, respectively, for poly(3-hydroxybutyrate) (PHB) production. A cell dry weight (CDW) of up to 10 g/L and PHB content of 51.7 wt% were obtained after 48 h of cultivation in flask experiment. Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] was synthesized when 1,4-butanediol, γ-butyrolactone, or sodium 4-hydroxybutyrate was added as precursors to the culture medium. The biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] was achieved by supplying precursors such as sodium valerate, sodium propionate, and sodium heptanoate. Salinivibrio sp. M318 was able to accumulate the above mentioned PHAs during the growth phase. High CDW of 69.1 g/L and PHB content of 51.5 wt% were obtained by strain Salinivibrio sp. M318 after 78 h of cultivation in fed-batch culture. The results demonstrate Salinivibrio sp. M318 to be a promising wild-type bacterium for the production of PHA from aquaculture residues.
    Matched MeSH terms: Polyhydroxyalkanoates/analysis; Polyhydroxyalkanoates/biosynthesis*
  8. Genome Mining Reveals the Biosynthetic Pathways of Polyhydroxyalkanoate and Ectoines of the Halophilic Strain Salinivibrio proteolyticus M318 Isolated from Fermented Shrimp Paste
    Van Thuoc D, Loan TT, Trung TA, Van Quyen N, Tung QN, Tien PQ, et al.
    Mar Biotechnol (NY), 2020 Oct;22(5):651-660.
    PMID: 32827070 DOI: 10.1007/s10126-020-09986-z
    Salinivibrio proteolyticus M318, a halophilic bacterium isolated from fermented shrimp paste, is able to produce polyhydroxyalkanoate (PHA) from different carbon sources. In this study, we report the whole-genome sequence of strain M138, which comprises 2 separated chromosomes and 2 plasmids, and the complete genome contains 3,605,935 bp with an average GC content of 49.9%. The genome of strain M318 contains 3341 genes, 98 tRNA genes, and 28 rRNA genes. The 16S rRNA gene sequence and average nucleotide identity analysis associated with morphological and biochemical tests showed that this strain has high homology to the reference strain Salinivibrio proteolyticus DSM 8285. The genes encoding key enzymes for PHA and ectoine synthesis were identified from the bacterial genome. In addition, the TeaABC transporter responsible for ectoine uptake from the environment and the operon doeABXCD responsible for the degradation of ectoine were also detected. Strain M318 was able to produce poly(3-hydroxybutyrate) [P(3HB)] from different carbon sources such as glycerol, maltose, glucose, fructose, and starch. The ability to produce ectoines at different NaCl concentrations was investigated. High ectoine content of 26.2% of cell dry weight was obtained by this strain at 18% NaCl. This report provides genetic information regarding adaptive mechanisms of strain M318 to stress conditions, as well as new knowledge to facilitate the application of this strain as a bacterial cell factory for the production of PHA and ectoine.
    Matched MeSH terms: Polyhydroxyalkanoates/biosynthesis*
  9. Modelling of polyhydroxyalkanoate synthase from Aquitalea sp. USM4 suggests a novel mechanism for polymer elongation
    Teh AH, Chiam NC, Furusawa G, Sudesh K
    Int J Biol Macromol, 2018 Nov;119:438-445.
    PMID: 30048726 DOI: 10.1016/j.ijbiomac.2018.07.147
    Polyhydroxyalkanoate (PHA) synthase, PhaC, is a key enzyme in the biosynthesis of PHA, a type of bioplastics with huge potential to replace petroleum-based plastics. While two structures have been determined, the exact mechanism remains unclear partly due to the absence of a tunnel for product passage. A model of the class I PhaC from Aquitalea sp. USM4, characterised with Km of 394 μM and kcat of 476 s-1 on 3-(R)-hydroxybutyryl-CoA, revealed a three-branched channel at the dimeric interface. Two of them are opened to the solvent and are expected to serve as the putative routes for substrate entrance and product exit, while the third is elongated in the class II PhaC1 model from Pseudomonas aeruginosa, indicating a role in accommodating the hydroxyalkanoate (HA) moiety of a HA-CoA substrate. Docking of the two tetrahedral intermediates, formed during the transfer of the growing PHA chain from the catalytic Cys to a new molecule of substrate and back to Cys, suggests a common elongation mechanism requiring the HA moiety of the ligand to rotate ~180°. Substrate specificity is determined in part by a bulky Phe/Tyr/Trp residue in the third branch in class I, which is conserved as Ala in class II to create room for longer substrates.
    Matched MeSH terms: Polyhydroxyalkanoates/metabolism*; Polyhydroxyalkanoates/chemistry*
  10. Polyhydroxyalkanoate (PHA) synthase genes and PHA-associated gene clusters in Pseudomonas spp. and Janthinobacterium spp. isolated from Antarctica
    Tan IKP, Foong CP, Tan HT, Lim H, Zain NA, Tan YC, et al.
    J Biotechnol, 2020 Apr 10;313:18-28.
    PMID: 32171790 DOI: 10.1016/j.jbiotec.2020.03.006
    The polyhydroxyalkanoate (PHA) producing capability of four bacterial strains isolated from Antarctica was reported in a previous study. This study analyzed the PHA synthase genes and the PHA-associated gene clusters from the two antarctic Pseudomonas isolates (UMAB-08 and UMAB-40) and the two antarctic Janthinobacterium isolates (UMAB-56 and UMAB-60) through whole-genome sequence analysis. The Pseudomonas isolates were found to carry PHA synthase genes which fall into two different PHA gene clusters, namely Class I and Class II, which are involved in the biosynthesis of short-chain-length-PHA (SCL-PHA) and medium-chain-length-PHA (MCL-PHA), respectively. On the other hand, the Janthinobacterium isolates carry a Class I and an uncharacterized putative PHA synthase genes. No other gene involved in PHA synthesis was detected in close proximity to the uncharacterized putative PHA synthase gene in the Janthinobacterium isolates, therefore it falls into a separate clade from the ordinary Class I, II, III and IV clades of PHA synthase (PhaC) phylogenetic tree. Multiple sequence alignment showed that the uncharacterized putative PHA synthase gene contains all the highly conserved amino acid residues and the proposed catalytic triad of PHA synthase. PHA biosynthesis and in vitro PhaC enzymatic assay results showed that this uncharacterized putative PHA synthase from Janthinobacterium sp. UMAB-60 is funtional. This report adds new knowledge to the PHA synthase database as we describe scarce information of PHA synthase genes and PHA-associated gene clusters from the antarctic bacterial isolates (extreme and geographically isolated environment) and comparing with those from non-antarctic PHA-producing bacteria.
    Matched MeSH terms: Polyhydroxyalkanoates
  11. Evaluation of BP-M-CPF4 polyhydroxyalkanoate (PHA) synthase on the production of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) from plant oil using Cupriavidus necator transformants
    Tan HT, Chek MF, Lakshmanan M, Foong CP, Hakoshima T, Sudesh K
    Int J Biol Macromol, 2020 Sep 15;159:250-257.
    PMID: 32417540 DOI: 10.1016/j.ijbiomac.2020.05.064
    Among the various types of polyhydroxyalkanoate (PHA), poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate] [P(3HB-co-3HHx)] has a high potential to serve as commercial bioplastic due to its striking resemblance to petroleum-based plastics. In this study, five different genotypes of Cupriavidusnecator transformants harbouring the phaCBP-M-CPF4 gene (including PHB¯4/pBBR1-CBP-M-CPF4) were developed to evaluate the efficiency of 3HHx monomer incorporation. The fraction of 3-hydroxyhexanoate (3HHx) monomer that was incorporated into the PHA synthesized by these C. necator transformants using palm oil as the sole carbon source, was examined. Overall, co-expression of enoyl-CoA hydratase gene (phaJ1) from Pseudomonas aeruginosa, along with PHA synthase (PhaC), increased the 3HHx composition in the PHA copolymer. The differences in the enzyme activities of β-ketothiolase (PhaACn) and NADPH-dependent acetoacetyl-CoA reductase (PhaBCn) of the C. necator mutant hosts used in this study, were observed to alter the 3HHx composition and molecular weight of the PHA copolymer produced. The 3HHx fractions in the P(3HB-co-3HHx) produced by these C. necator transformants ranged between 1 and 18 mol%, while the weight-average molecular weight ranged from 0.7 × 106 to 1.8 × 106 Da. PhaCBP-M-CPF4 displayed a typical initial lag-phase and a relatively low synthase activity in the in vitro enzyme assay, which is thought to be the reason for the higher molecular weights of PHA obtained in this study.
    Matched MeSH terms: Polyhydroxyalkanoates/biosynthesis
  12. Discovery of a new polyhydroxyalkanoate synthase from limestone soil through metagenomic approach
    Tai YT, Foong CP, Najimudin N, Sudesh K
    J Biosci Bioeng, 2016 Apr;121(4):355-64.
    PMID: 26467694 DOI: 10.1016/j.jbiosc.2015.08.008
    PHA synthase (PhaC) is the key enzyme in the production of biodegradable plastics known as polyhydroxyalkanoate (PHA). Nevertheless, most of these enzymes are isolated from cultivable bacteria using traditional isolation method. Most of the microorganisms found in nature could not be successfully cultivated due to the lack of knowledge on their growth conditions. In this study, a culture-independent approach was applied. The presence of phaC genes in limestone soil was screened using primers targeting the class I and II PHA synthases. Based on the partial gene sequences, a total of 19 gene clusters have been identified and 7 clones were selected for full length amplification through genome walking. The complete phaC gene sequence of one of the clones (SC8) was obtained and it revealed 81% nucleotide identity to the PHA synthase gene of Chromobacterium violaceum ATCC 12472. This gene obtained from uncultured bacterium was successfully cloned and expressed in a Cupriavidus necator PHB(-)4 PHA-negative mutant resulting in the accumulation of significant amount of PHA. The PHA synthase activity of this transformant was 64 ± 12 U/g proteins. This paper presents a pioneering study on the discovery of phaC in a limestone area using metagenomic approach. Through this study, a new functional phaC was discovered from uncultured bacterium. Phylogenetic classification for all the phaCs isolated from this study has revealed that limestone hill harbors a great diversity of PhaCs with activities that have not yet been investigated.
    Matched MeSH terms: Polyhydroxyalkanoates
  13. The oil-absorbing property of polyhydroxyalkanoate films and its practical application: a refreshing new outlook for an old degrading material
    Sudesh K, Loo CY, Goh LK, Iwata T, Maeda M
    Macromol Biosci, 2007 Nov 12;7(11):1199-205.
    PMID: 17703476
    Polyhydroxyalkanoates (PHAs) have attracted the attention of academia and industry because of their plastic-like properties and biodegradability. However, practical applications as a commodity material have not materialized because of their high production cost and unsatisfactory mechanical properties. PHAs are also believed to have high-value applications as an absorbable biomaterial for tissue engineering and drug-delivery devices because of their biocompatibility. However, research in these areas is still in its very early stages. The main problem faced by proponents of PHAs is the lack of a niche area where PHAs will be the most desired material in terms of its function during use rather than because of its eco-friendly virtues after use. Here, we report on the oil-absorbing property of PHA films and its potential applications. By comparing with some of the existing commercial products, the potential application of PHAs as cosmetic oil-blotting films is revealed for the first time. Besides having the ability to rapidly absorb and retain oil, PHA films also have a natural oil-indicator property, showing obvious changes in opacity following oil absorption. Surface analysis revealed that the surface structures such as porosity and smoothness exert great influence on the rapid oil-absorption properties of the PHA films. These newly discovered properties could be exploited to create a niche area for the practical applications of PHAs.
    Matched MeSH terms: Polyhydroxyalkanoates/pharmacokinetics*; Polyhydroxyalkanoates/chemistry*
  14. Synthesis of polyhydroxyalkanoate from palm oil and some new applications
    Sudesh K, Bhubalan K, Chuah JA, Kek YK, Kamilah H, Sridewi N, et al.
    Appl Microbiol Biotechnol, 2011 Mar;89(5):1373-86.
    PMID: 21279347 DOI: 10.1007/s00253-011-3098-5
    Polyhydroxyalkanoate (PHA) is a potential substitute for some petrochemical-based plastics. This biodegradable plastic is derived from microbial fermentation using various carbon substrates. Since carbon source has been identified as one of the major cost-absorbing factors in PHA production, cheap and renewable substrates are currently being investigated as substitutes for existing sugar-based feedstock. Plant oils have been found to result in high-yield PHA production. Malaysia, being the world's second largest producer of palm oil, is able to ensure continuous supply of palm oil products for sustainable PHA production. The biosynthesis and characterization of various types of PHA using palm oil products have been described in detail in this review. Besides, by-products and waste stream from palm oil industry have also demonstrated promising results as carbon sources for PHA biosynthesis. Some new applications in cosmetic and wastewater treatment show the diversity of PHA usage. With proper management practices and efficient milling processes, it may be possible to supply enough palm oil-based raw materials for human consumption and other biotechnological applications such as production of PHA in a sustainable manner.
    Matched MeSH terms: Polyhydroxyalkanoates/biosynthesis*
  15. Composite of medium-chain-length polyhydroxyalkanoates-co-methyl acrylate and carbon nanotubes as innovative electrodes modifier in microbial fuel cell
    Sirajudeen AAO, Annuar MSM, Subramaniam R
    Biotechnol Appl Biochem, 2021 Apr;68(2):307-318.
    PMID: 32314420 DOI: 10.1002/bab.1928
    A microbial fuel cell is a sustainable and environmental-friendly device that combines electricity generation and wastewater treatment through metabolic activities of microorganisms. However, low power output from inadequate electron transfer to the anode electrode hampers its practical implementation. Nanocomposites of oxidized carbon nanotubes and medium-chain-length polyhydroxyalkanoates (mcl-PHA) grafted with methyl acrylate monomers enhance the electrochemical function of electrodes in microbial fuel cell. Extensive polymerization of methyl acrylate monomers within mcl-PHA matrix, and homogenous dispersion of carbon nanotubes within the graft matrix are responsible for the enhancement. Modified electrodes exhibit high conductivities, better redox peak and reduction of cell internal resistance up to 76%. A stable voltage output at almost 700 mV running for 225 H generates maximum power and current density of 351 mW/m2 and 765 mA/m2 , respectively. Superior biofilm growth on modified surface is responsible for improved electron transfer to the anode hence stable and elevated power output generation.
    Matched MeSH terms: Polyhydroxyalkanoates/chemistry*
  16. Fulltext Complete Genome Sequences of Three Cupriavidus Strains Isolated from Various Malaysian Environments
    Shafie NA, Lau NS, Ramachandran H, Amirul AA
    Genome Announc, 2017 Jan 19;5(3).
    PMID: 28104662 DOI: 10.1128/genomeA.01498-16
    Cupriavidus sp. USMAA1020, USMAA2-4, and USMAHM13 are capable of producing polyhydroxyalkanoate (PHA). This biopolymer is an alternative solution to synthetic plastics, whereby polyhydroxyalkanoate synthase is the key enzyme involved in PHA biosynthesis. Here, we report the complete genomes of three Cupriavidus sp. strains: USMAA1020, USMAA2-4, and USMAHM13.
    Matched MeSH terms: Polyhydroxyalkanoates
  17. Environmental degradation of microbial polyhydroxyalkanoates and oil palm-based composites
    Salim YS, Sharon A, Vigneswari S, Mohamad Ibrahim MN, Amirul AA
    Appl Biochem Biotechnol, 2012 May;167(2):314-26.
    PMID: 22544728 DOI: 10.1007/s12010-012-9688-6
    This paper investigates the degradation of polyhydroxyalkanoates and its biofiber composites in both soil and lake environment. Time-dependent changes in the weight loss of films were monitored. The rate of degradation of poly(3-hydroxybutyrate) [P(3HB)], poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-23 mol% 4HB)] and poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-4-hydroxybutyrate) [P(3HB-co-9 mol% 3HV-co-19 mol% 4HB)] were investigated. The rate of degradation in the lake is higher compared to that in the soil. The highest rate of degradation in lake environment (15.6% w/w week(-1)) was observed with P(3HB-co-3HV-co-4HB) terpolymer. Additionally, the rate of degradation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-38 mol% 3HV)] was compared to PHBV biofiber composites containing compatibilizers and empty fruit bunch (EFB). Here, composites with 30% EFB displayed the highest rate of degradation both in the lake (25.6% w/w week(-1)) and soil (15.6% w/w week(-1)) environment.
    Matched MeSH terms: Polyhydroxyalkanoates/metabolism*; Polyhydroxyalkanoates/chemistry
  18. Fulltext Metabolic potential of the moderate halophile Yangia sp. ND199 for co-production of polyhydroxyalkanoates and exopolysaccharides
    Romero Soto L, Thabet H, Maghembe R, Gameiro D, Van-Thuoc D, Dishisha T, et al.
    Microbiologyopen, 2021 01;10(1):e1160.
    PMID: 33650793 DOI: 10.1002/mbo3.1160
    Yangia sp. ND199 is a moderately halophilic bacterium isolated from mangrove samples in Northern Vietnam, which was earlier reported to grow on several sugars and glycerol to accumulate poly(hydroxyalkanoates) (PHA). In this study, the potential of the bacterium for co-production of exopolysaccharides (EPS) and PHA was investigated. Genome sequence analysis of the closely related Yangia sp. CCB-M3 isolated from mangroves in Malaysia revealed genes encoding enzymes participating in different EPS biosynthetic pathways. The effects of various cultivation parameters on the production of EPS and PHA were studied. The highest level of EPS (288 mg/L) was achieved using sucrose and yeast extract with 5% NaCl and 120 mM phosphate salts but with modest PHA accumulation (32% of cell dry weight, 1.3 g/L). Growth on fructose yielded the highest PHA concentration (85% of CDW, 3.3 g/L) at 90 mM phosphate and higher molecular weight EPS at 251 mg/L yield at 120 mM phosphate concentration. Analysis of EPS showed a predominance of glucose, followed by fructose and galactose, and minor amounts of acidic sugars.
    Matched MeSH terms: Polyhydroxyalkanoates/biosynthesis*
  19. Fulltext Polyhydroxyalkanoate biosynthesis and simplified polymer recovery by a novel moderately halophilic bacterium isolated from hypersaline microbial mats
    Rathi DN, Amir HG, Abed RM, Kosugi A, Arai T, Sulaiman O, et al.
    J Appl Microbiol, 2013 Feb;114(2):384-95.
    PMID: 23176757 DOI: 10.1111/jam.12083
    Halophilic micro-organisms have received much interest because of their potential biotechnological applications, among which is the capability of some strains to synthesize polyhydroxyalkanoates (PHA). Halomonas sp. SK5, which was isolated from hypersaline microbial mats, accumulated intracellular granules of poly(3-hydroxybutyrate) [P(3HB)] in modified accumulation medium supplemented with 10% (w/v) salinity and 3% (w/v) glucose.
    Matched MeSH terms: Polyhydroxyalkanoates/biosynthesis*; Polyhydroxyalkanoates/isolation & purification; Polyhydroxyalkanoates/chemistry
  20. Exploration of Global Trend on Biomedical Application of Polyhydroxyalkanoate (PHA): A Patent Survey
    Paulraj P, Vnootheni N, Chandramohan M, Thevarkattil MJP
    Recent Pat Biotechnol, 2018;12(3):186-199.
    PMID: 29384069 DOI: 10.2174/1872208312666180131114125
    BACKGROUND: Polyhydroxyalkanoates are bio-based, biodegradable naturally occurring polymers produced by a wide range of organisms, from bacteria to higher mammals. The properties and biocompatibility of PHA make it possible for a wide spectrum of applications. In this context, we analyze the potential applications of PHA in biomedical science by exploring the global trend through the patent survey. The survey suggests that PHA is an attractive candidate in such a way that their applications are widely distributed in the medical industry, drug delivery system, dental material, tissue engineering, packaging material as well as other useful products.

    OBJECTIVE: In our present study, we explored patents associated with various biomedical applications of polyhydroxyalkanoates.

    METHOD: Patent databases of European Patent Office, United States Patent and Trademark Office and World Intellectual Property Organization were mined. We developed an intensive exploration approach to eliminate overlapping patents and sort out significant patents.We demarcated the keywords and search criterions and established search patterns for the database request. We retrieved documents within the recent 6 years, 2010 to 2016 and sort out the collected data stepwise to gather the most appropriate documents in patent families for further scrutiny.

    RESULTS: By this approach, we retrieved 23,368 patent documents from all the three databases and the patent titles were further analyzed for the relevance of polyhydroxyalkanoates in biomedical applications. This ensued in the documentation of approximately 226 significant patents associated with biomedical applications of polyhydroxyalkanoates and the information was classified into six major groups. Polyhydroxyalkanoates has been patented in such a way that their applications are widely distributed in the medical industry, drug delivery system, dental material, tissue engineering, packagingmaterial as well as other useful products.

    CONCLUSION: There are many avenues through which PHA & PHB could be used. Our analysis shows patent information can be used to identify various applications of PHA and its representatives in the biomedical field. Upcoming studies can focus on the application of PHA in the different field to discover the related topics and associate to this study.We believe that this approach of analysis and findings can initiate new researchers to undertake similar kind of studies in their represented field to fill the gap between the patent articles and research publications.

    Matched MeSH terms: Polyhydroxyalkanoates*
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