The growth-inhibitory effects of pawpaw (Asimina triloba [L.] Dunal) roots, twigs, leaves, and fruit against human gastric (AGS) and cervical (HeLa) cancer cells and their anti-inflammatory activities.

BACKGROUND: The pawpaw tree has several beneficial effects. However, no studies have been conducted to address the mechanisms underlying the cytotoxic effects of pawpaw extracts against cancer cells, and no study has investigated the anti-inflammatory effects. Hence, in this study, the growth-inhibitory effects of pawpaw (Asimina triloba [L.] Dunal) extracts against gastric (AGS) and cervical (HeLa) cancer cells and the inhibitory effects of pawpaw extracts against inflammatory factors (NO, TNF-α, IL-6, iNOS, and COX-2) were investigated. METHODS AND RESULTS: The viability of AGS and HeLa cells, the analysis of cell cycle, and the expression of apoptosis marker protein were determined using MTT assay, FACS, western blotting, and TUNEL assays. The inflammatory factors were determined using Griess method, ELISA assay kit, and RAW 264.7 cells. The IC50 values of twig and unripe fruit extracts for AGS cells were 82.01 and 100.61 µg/mL, respectively. For HeLa cells, pawpaw twig extracts exhibited the strongest ability to inhibit cervical cancer cell growth (IC50 = 97.73 µg/mL). Analysis of the cell cycle phase distribution and expression of the apoptosis regulatory proteins BCL-2, BAX, caspase-3, and PARP showed that pawpaw twig, root, and unripe fruit extracts induced Sub G1 cell cycle arrest and apoptosis of AGS and HeLa cells. In addition, the twig, root, and unripe fruit extracts of pawpaw effectively inhibited the inflammatory makers NO, TNF-α, IL-6, and iNOS. Particularly, the twig, root, and unripe fruit extracts at concentrations of 50 µg/mL exhibited > 50% inhibition of TNF-α. CONCLUSIONS: These findings indicate that pawpaw extracts are natural therapeutic agents that may be used for the prevention and treatment of gastric and cervical cancers, and encourage further studies on the anti-inflammatory potential of the pawpaw tree.

Preparation and In Vitro Release Studies of Ibuprofen Loaded Nanoparticles Made from PHO and PEGMA-g-PHO.

Monoacrylate-poly(ethylene glycol) grafted poly(3-hydroxyoctanoate) (PEGMA-g-PHO) copolymer was obtained by UV irradiation and ibuprofen (IBU) loaded nanoparticles with PHO or PEGMA-g-PHO polymers were successfully prepared by a single emulsion process. Size of IBU-loaded nanoparticles was about 300 nm based on particle size measurement. Their shapes were spherical. To study drug release properties, IBU release from nanoparticles were performed with FBS buffer. Higher burst release of IBU was observed with the highest graft density of PEGMA groups and 100% drug release was found in 3, 6, and 12 days for PHO, PEGMA-g-PHO0.05, and PEGMA-g-PHO0.15, respectively. Our results suggest that hydrophobic PHO and more hydrophilic PEGMA-g-PHO could be regarded as good candidates of drug release carriers.

Analysis of Medium-Chain-Length Polyhydroxyalkanoate-Producing Bacteria in Activated Sludge Samples Enriched by Aerobic Periodic Feeding.

Analysis of mixed microbial populations responsible for the production of medium-chain-length polyhydroxyalkanoates (MCL-PHAs) under periodic substrate feeding in a sequencing batch reactor (SBR) was conducted. Regardless of activated sludge samples and the different MCL alkanoic acids used as the sole external carbon substrate, denaturing gradient gel electrophoresis analysis indicated that Pseudomonas aeruginosa was the dominant bacterium enriched during the SBR process. Several P. aeruginosa strains were isolated from the enriched activated sludge samples. The isolates were subdivided into two groups, one that produced only MCL-PHAs and another that produced both MCL- and short-chain-length PHAs. The SBR periodic feeding experiments with five representative MCL-PHA-producing Pseudomonas species revealed that P. aeruginosa has an advantage over other species that enables it to become dominant in the bacterial community.

Biocatalytic characterization of an endo-ß-1,4-mannanase produced by Paenibacillus sp. strain HY-8.

OBJECTIVES: To evaluate the biocatalytic characteristics of a new endo-ß-1,4-D-mannan-degrading enzyme (ManP) from Paenibacillus sp. strain HY-8, a gut bacterium of the longicorn beetle Moechotypa diphysis. RESULTS: Purified ManP (32 kDa) with an N-terminal amino acid sequence of APSFAVGADFSYVPG displayed the greatest degree of biocatalytic activity toward locust bean gum (LBG) at 55 °C and pH 7.0. The enzyme degraded LBG, guar gum, ivory nut mannan, and mannooligosaccharides (M2-M5), but did not exhibit any hydrolytic activity against structurally unrelated substrates. The biocatalytic activity of ManP against LBG and guar gum was 695 and 450 U mg-1, respectively. Especially, enzymatic hydrolysis of mannobiose yielded a mixture of mannose (16.6 %) and mannobiose (83.4 %), although the degree of mannobiose degradation by ManP with was relatively limited. CONCLUSION: The present results suggest that ManP is an endo-ß-1,4-mannanase and is distinct from various other characterized endo-ß-1,4-mannanases.

Genetic and functional characterization of an extracellular modular GH6 endo-ß-1,4-glucanase from an earthworm symbiont, Cellulosimicrobium funkei HY-13.

The gene (1608-bp) encoding a GH6 endo-ß-1,4-glucanase (CelL) from the earthworm-symbiotic bacterium Cellulosimicrobium funkei HY-13 was cloned from its whole genome sequence, expressed recombinantly, and biochemically characterized. CelL (56.0 kDa) is a modular enzyme consisting of an N-terminal catalytic GH6 domain (from Val57 to Pro396), which is 71 % identical to a GH6 protein (accession no.: WP_034662937) from Cellulomonas sp. KRMCY2, together with a C-terminal CBM 2 domain (from Cys429 to Cys532). The highest catalytic activity of CelL toward carboxymethylcellulose (CMC) was observed at 50 °C and pH 5.0, and was relatively stable at a broad pH range of 4.0-10.0. The enzyme was capable of efficiently hydrolyzing the cellulosic polymers in the order of barley ß-1,3-1,4-D-glucan > CMC > lichenan > Avicel > konjac glucomannan. However, cellobiose, cellotriose, p-nitrophenyl derivatives of mono- and disaccharides, or structurally unrelated carbohydrate polymers including ß-1,3-D-glucan, ß-1,4-D-galactomannan, and ß-1,4-D-xylan were not susceptible to CelL. The enzymatic hydrolysis of cellopentaose resulted in the production of a mixture of 68.6 % cellobiose and 31.4 % cellotriose but barley ß-1,3-1,4-D-glucan was 100 % degraded to cellotriose by CelL. The enzyme strongly bound to Avicel, ivory nut mannan, and chitin but showed relatively weak binding affinity to lichenan, lignin, or poly(3-hydroxybutyrate) granules.

Polyester synthesis genes associated with stress resistance are involved in an insect-bacterium symbiosis.

Many bacteria accumulate granules of polyhydroxyalkanoate (PHA) within their cells, which confer resistance to nutritional depletion and other environmental stresses. Here, we report an unexpected involvement of the bacterial endocellular storage polymer, PHA, in an insect-bacterium symbiotic association. The bean bug Riptortus pedestris harbors a beneficial and specific gut symbiont of the ß-proteobacterial genus Burkholderia, which is orally acquired by host nymphs from the environment every generation and easily cultivable and genetically manipulatable. Biochemical and cytological comparisons between symbiotic and cultured Burkholderia detected more PHA granules consisting of poly-3-hydroxybutyrate and associated phasin (PhaP) protein in the symbiotic Burkholderia. Among major PHA synthesis genes, phaB and phaC were disrupted by homologous recombination together with the phaP gene, whereby ΔphaB, ΔphaC, and ΔphaP mutants were generated. Both in culture and in symbiosis, accumulation of PHA granules was strongly suppressed in ΔphaB and ΔphaC, but only moderately in ΔphaP. In symbiosis, the host insects infected with ΔphaB and ΔphaC exhibited significantly lower symbiont densities and smaller body sizes. These deficient phenotypes associated with ΔphaB and ΔphaC were restored by complementation of the mutants with plasmids encoding a functional phaB/phaC gene. Retention analysis of the plasmids revealed positive selection acting on the functional phaB/phaC in symbiosis. These results indicate that the PHA synthesis genes of the Burkholderia symbiont are required for normal symbiotic association with the Riptortus host. In vitro culturing analyses confirmed vulnerability of the PHA gene mutants to environmental stresses, suggesting that PHA may play a role in resisting stress under symbiotic conditions.

Overexpression of the (R)-specific enoyl-CoA hydratase gene from Pseudomonas chlororaphis HS21 in Pseudomonas strains for the biosynthesis of polyhydroxyalkanoates of altered monomer composition.

The (R)-specific enoyl-CoA hydratase gene (phaJ(HS21)) from Pseudomonas chlororaphis HS21 was overexpressed in various Pseudomonas strains, alone and in combination with the polyhydroxyalkanoate synthase gene (phaC(HS21)), for the biosynthesis of polyhydroxyalkanoates (PHAs) of altered monomer composition. Recombinant Pseudomonas strains harboring phaC(HS21) and phaJ(HS21) generated saturated and unsaturated monomers of C12-C14 in their PHAs. In particular, the level of the 3-hydroxytetradecenoate monomer in recombinant P. chlororaphis HS21 increased by approximately 260%. PhaJ(HS21) is expected to be useful in the biosynthesis of PHAs consisting of unusual monomer units.

Analysis of Bacterial Community in the Ginseng Soil Using Denaturing Gradient Gel Electrophoresis (DGGE).

The objective of this work was to determine the shifts in the PCR-DGGE profiles of bacterial communities associated with the rhizosphere soil of ginseng at varying age levels. Differences in the dominance of intense DNA bands in the DGGE profile was observed over the age of the plants indicating the fluctuation in the microbial community structure. The bacterial orders of actinomycetales of Actinobacteria and Spingomonadales and Rhizobiales of α-Proteobacteria were predominant in the ginseng soil.

Phenolic Profiles, Antioxidant and Antimicrobial Activities of Pawpaw Pulp (Asimina triloba [L.] Dunal) at Different Ripening Stages.

In this study, the phenolic components, as well as the antioxidant and antimicrobial activities, of the ripe and unripe fruit of pawpaw (Asimina triloba [L.] Dunal) extracted using five different solvents (distilled water, 95% methanol, 80% methanol, 95% ethanol, and 80% ethanol) were analyzed. The total phenolic content and total flavonoid content were the highest in the 95% ethanol (149.50 mg CAE/g) and 80% ethanol (5.62 mg RE/g) extracts of the unripe fruit, respectively. Analysis of 17 phenolic compounds in pawpaw extracts revealed that epigallocatechin, epicatechin, and p-coumaric acid were the as major compounds, and the amounts of all components significantly decreased with the ripening (P < 0.05). In all antioxidant assays, the 95% ethanol extract of the unripe fruit showed the highest antioxidant activity (EC50 0.22 to 0.93 mg/mL). The pawpaw extracts were more sensitive against Corynebacterium xerosis and Clostridium perfringens. In particular, the 95% ethanol extract of the ripe fruit notably inhibited C. xerosis growth, with minimum inhibitory concentration of 1.56 mg/mL. These results showed that the unripe fruit of pawpaw has abundant phenolic compounds and superior antioxidant activity, and that the 95% ethanol extract of the ripe fruit shows strong inhibitory activity against various microorganisms. Therefore, pawpaw fruit can be utilized as an attractive source of nutrients and therapeutic agents. PRACTICAL APPLICATION: In this study, we identified that the unripe fruit of pawpaw is rich in phenolic compounds and shows strong antioxidant activities. The 95% ethanol extract of the ripe fruit showed strong high inhibitory effect against various microorganisms. These results suggest that pawpaw fruit can serve as a source of antioxidants and delay the aging process. In addition, the fruit could also potentially be utilized as a potential antimicrobial agent.

Shape-dependent antimicrobial activities of silver nanoparticles.

Purpose: An important application of silver nanoparticles (Ag NPs) is their use as an antimicrobial and wound dressing material. The aim of this study is to investigate the morphological dependence on the antimicrobial activity and cellular response of Ag NPs. Materials and methods: Ag NPs of various shapes were synthesized in an aqueous solution using a simple method. The morphology of the synthesized Ag NPs was observed via TEM imaging. The antimicrobial activity of the Ag NPs with different morphologies was evaluated against various microorganisms (Escherichia coli [E. coli], Staphylococcus aureus [S. aureus], Pseudomonas aeruginosa [P. aeruginosa]). The antimicrobial activity of the Ag NPs was also examined according to the concentration in terms of the growth rate of E. coli. Results: The TEM images indicated that the Ag NPs with different morphologies (sphere, disk and triangular plate) had been successfully synthesized. The antimicrobial activity obtained from the inhibition zone was in the order of spherical Ag NPs > disk Ag NPs > triangular plate Ag NPs. In contrast, fibroblast cells grew well in all types of Ag NPs when the cell viability was evaluated via an MTT assay. An inductively coupled plasma mass assay showed that the difference in the antimicrobial activities of the Ag NPs was closely associated with the difference in the release rate of the Ag ions due to the difference in the surface area of the Ag NPs. Conclusion: The morphological dependence of the antimicrobial activity of the Ag NPs can be explained by the difference in the Ag ion release depending on the shape. Therefore, it will be possible to control the antimicrobial activity by controlling the shape and size of the Ag NPs.

Stable expression and secretion of polyhydroxybutyrate depolymerase of Paucimonas lemoignei in Escherichia coli.

An efficient strategy for the expression and secretion of extracellular polyhydroxybutyrate depolymerase (PhaZ1) of Paucimonas lemoignei in Escherichia coli was developed by employing the signal peptide of PhaZ1 and a truncated ice nucleation protein anchoring motif (INPNC). Directly synthesized mature form of Phaz1 was present in the cytoplasm of host cells as inclusion bodies, while a construct containing Phaz1 and its own N-terminal signal peptide (PrePhaz1) enabled the secretion of active Phaz1 into the extracellular medium. However, the PrePhaz1 construct was harmful to the host cell and resulted in atypical growth and instability of the plasmid during the cultivation. In contrast, INPNC-Phaz1 and INPNC-PrePhaz1 fusion constructs did not affect growth of host cells. INPNC-Phaz1 was successfully displayed on the cell surface with its fusion form, but did not retain Phaz1 activity. In the case of INPNC-PrePhaz1, the initially synthesized fusion form was separated by precise cleavage of the signal peptide, and active Phaz1 was consequently released into the culture medium. The amount of Phaz1 derived from E. coli (INPNC-PrePhaz1) was almost twice as great as that directly expressed from E. coli (PrePhaz1), and was predominantly (approximately 85%) located in the periplasm when cultivated at 22 degrees C but was efficiently secreted into the extracellular medium when cultivated at 37 degrees C.

Graft copolymerization of glycerol 1,3-diglycerolate diacrylate onto poly(3-hydroxyoctanoate) to improve physical properties and biocompatibility.

Glycerol 1,3-diglycerol diacrylate-grafted poly(3-hydroxyoctanoate) (GDD-g-PHO) copolymers were prepared by heating homogeneous solutions of PHO, GDD monomer and benzoylperoxide initiator. Experiments showed that GDD was successfully grafted onto the PHO chains and that the resulting copolymers had enhanced thermal properties and mechanical strengths. The surfaces and the bulk of GDD-g-PHO copolymers became more hydrophilic as the GDD grafting density in the copolymer increased. Measurements of the growth of Chinese hamster ovary cells and the adsorption of blood proteins and platelets in vitro showed that biocompatibility was also enhanced by grafting of GDD groups. These results indicate that the GDD-g-PHO copolymers are promising materials for biocompatible biomedical applications.

Bioleaching of metals from spent lithium ion secondary batteries using Acidithiobacillus ferrooxidans.

Bioleaching of spent lithium ion secondary batteries, containing LiCoO2, was attempted in this investigation. The present study was carried out using chemolithotrophic and acidophilic bacteria Acidithiobacillus ferrooxidans, which utilized elemental sulfur and ferrous ion as the energy source to produce metabolites like sulfuric acids and ferric ion in the leaching medium. These metabolites helped dissolve metals from spent batteries. Bio-dissolution of cobalt was found to be faster than lithium. The effect of initial Fe(II) concentration, initial pH and solid/liquid (w/v) ratio during bioleaching of spent battery wastes were studied in detail. Higher Fe(II) concentration showed a decrease in dissolution due co-precipitation of Fe(III) with the metals in the residues. The higher solid/liquid ratio (w/v) also affected the metal dissolution by arresting the cell growth due to increased metal concentration in the waste sample. An EDXA mapping was carried out to compare the solubility of both cobalt and lithium, and the slow dissolution rate was clearly found from the figures.

Preparation and biocompatibility of crosslinked poly(3-hydroxyundecenoate).

A sticky polymer, poly(3-hydroxyundecenoate) (PHU), was produced by Pseudomonas oleovorans when nonanoate and undecenoate were used as carbon sources. Crosslinked PHU (CL-PHU) was prepared by heating using benzoyl peroxide as a crosslinker. According to the degree of crosslinking in the polymer, three types of CL-PHU were prepared: CL-PHU50, CL-PHU60 and CL-PHU70. Fourier transform-infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry results suggested that crosslinking of PHU was successfully achieved by heat, which increased the crosslinking density and decreased stiffness and flexibility of the polymer. Water contact angle measurements revealed no differences of hydrophilicity as the crosslinking density. Slight morphological changes of CL-PHU film surfaces were observed by atomic force microscopy. Chinese hamster ovary cells were used to investigate the biocompatibility of CL-PHU films using poly(l-lactide) surfaces as control. Surface properties of the film, such as roughness and adhesive force, enhanced the adhesion and proliferation of cells on the films. CL-PHU might be useful for cell compatible biomedical applications.

Correlation Between Acetogenin Content and Antiproliferative Activity of Pawpaw (Asimina triloba [L.] Dunal) Fruit Pulp Grown in Korea.

Pawpaw (Asimina triloba [L.] Dunal) is widely cultivated in Korea for its fruit, which contains bioactive compounds, such as acetogenins. In this study, we investigated the acetogenin content and antiproliferative activity of pawpaw fruit pulp against various cancer cell lines and evaluated the relationship between these two variables at different maturation stages. Unripe fruit had higher antiproliferative activity than ripe fruit, and the activity level depended on acetogenin content. In addition, the presence of specific acetogenins was related to inhibition of certain cancer cell types. The unripe fruit methanol and ethanol extracts (URFM and URFE, respectively) that were rich in acetogenins strongly inhibited the growth of HT-1080, HeLa, and AGS cells by >50% at concentrations of less than 115 µg/mL. These findings indicate that URFM and URFE have therapeutic potential for the treatment of cancer, and our study establishes a basis for further mechanistic studies of the antiproliferative activity of pawpaw fruit. However, it is necessary to further study the anticancer activity of acetogenins from pawpaw fruit using in vivo activity approaches. PRACTICAL APPLICATION: Pawpaw (Asimina triloba) contains acetogenins that can inhibit the growth of cancer cells. In our study, we demonstrate that the antiproliferative activity is higher in unripe than in ripe fruit and depends on acetogenin content. Our results indicate that the extract of unripe pawpaw fruit has value not only as a functional food, but has therapeutic potential for the treatment of cancer as a naturally derived substance that may be less toxic than conventional chemotherapy drugs.

Genetic and functional characterization of a novel GH10 endo-ß- 1,4-xylanase with a ricin-type ß-trefoil domain-like domain from Luteimicrobium xylanilyticum HY-24.

The gene (1488-bp) encoding a novel GH10 endo-ß-1,4-xylanase (XylM) consisting of an N-terminal catalytic GH10 domain and a C-terminal ricin-type ß-trefoil lectin domain-like (RICIN) domain was identified from Luteimicrobium xylanilyticum HY-24. The GH10 domain of XylM was 72% identical to that of Micromonospora lupini endo-ß-1,4-xylanase and the RICIN domain was 67% identical to that of Actinospica robiniae hypothetical protein. The recombinant enzyme (rXylM: 49kDa) exhibited maximum activity toward beechwood xylan at 65°C and pH 6.0, while the optimum temperature and pH of its C-terminal truncated mutant (rXylM△RICIN: 35kDa) were 45°C and 5.0, respectively. After pre-incubation of 1h at 60°C, rXylM retained over 80% of its initial activity, but the thermostability of rXylM△RICIN was sharply decreased at temperatures exceeding 40°C. The specific activity (254.1Umg-1) of rXylM toward oat spelts xylan was 3.4-fold higher than that (74.8Umg-1) of rXylM△RICIN when the same substrate was used. rXylM displayed superior binding capacities to lignin and insoluble polysaccharides compared to rXylM△RICIN. Enzymatic hydrolysis of ß-1,4-d-xylooligosaccharides (X3-X6) and birchwood xylan yielded X3 as the major product. The results suggest that the RICIN domain in XylM might play an important role in substrate-binding and biocatalysis.

Biosynthesis, modification, and biodegradation of bacterial medium-chain-length polyhydroxyalkanoates.

Medium-chain-length polyhydroxyalkanoates (MCL-PHAs), which have constituents with a typical chain length of C6-C14, are polyesters that are synthesized and accumulated in a wide variety of Gram-negative bacteria, mainly pseudomonads. These biopolyesters are promising materials for various applications because they have useful mechanical properties and are biodegradable and biocompatible. The versatile metabolic capacity of some Pseudomonas spp. enables them to synthesize MCL-PHAs that contain various functional substituents; these MCL-PHAs are of great interest because these functional groups can improve the physical properties of the polymers, allowing the creation of tailor-made products. Moreover, some functional substituents can be modified by chemical reactions to obtain more useful groups that can extend the potential applications of MCL-PHAs as environmentally friendly polymers and functional biomaterials for use in biomedical fields. Although MCL-PHAs are water-insoluble, hydrophobic polymers, they can be degraded by microorganisms that produce extracellular MCL-PHA depolymerase. MCL-PHA-degraders are relatively uncommon in natural environments and, to date, only a limited number of MCL-PHA depolymerases have been investigated at the molecular level. All known MCL-PHA depolymerases share a highly significant similarity in amino acid sequences, as well as several enzymatic characteristics. This paper reviews recent advances in our knowledge of MCL-PHAs, with particular emphasis on the findings by our research group.

Preparation of alginate-quaternary ammonium complex beads and evaluation of their antimicrobial activity.

Alginate-quaternary ammonium complex beads with antimicrobial activity were prepared by the reaction of sodium alginate (SA) with 3-(trimethoxysilyl)propyl-octadecyldimethylammonium chloride (TSA) in acid solution, followed by crosslinking with CaCl(2). FTIR spectroscopy analysis showed that the resulting complex was formed mainly through covalent bonds between the hydroxyl groups of SA and the methoxysilyl groups of TSA. The complex beads exhibited a maximum swelling of 20% in water at 37 degrees C and were not hydrolyzed in water during experiments lasting for 30 days. The in vitro antimicrobial activity of the complex beads was evaluated against four species of bacteria and fungi. The test microorganisms were completely eliminated within 20 min when treated with 5% (v/v) complex beads, which showed a wide spectrum of excellent antimicrobial activity. The antimicrobial activity of the complex beads was retained after 10 cycles of washing and drying. The present results indicate that these SA-TSA complex beads are a new type of insoluble cationic polymer that can kill or remove microorganisms in water by mere contact without releasing the reactive agent.

Antioxidant Activities and Phenolic Compounds of Several Tissues of Pawpaw (Asimina triloba [L.] Dunal) Grown in Korea.

Pawpaw (Asimina triloba [L.] Dunal) possesses antioxidant compounds and strong inhibitors of cancer cells, and is widely cultivated in North America, Canada, and Korea. We analyzed the total phenolic and total flavonoid contents (TPC and TFC, respectively) of pawpaw plants grown in Korea and the antioxidant activities of their roots, twigs, leaves, and fruit with respect to 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging activity, 2,2'-azino-bis diammonium salt (ABTS) radical scavenging activity, ferrous (Fe2+ ) chelating ability, and nitrite scavenging activity. Pearson's correlation analyses revealed a linear correlation between TPC and antioxidant activities (r2 >0.69). Root methanol extracts had higher TPC and antioxidant activities than other extracts, which was also consistent with those from the phenolic compounds found in those extracts. Therefore, antioxidant activities seem to depend on the TPC of each pawpaw tissue and pawpaw roots might be useful as a natural source of natural antioxidants.

Production of Polyhydroxyalkanoates from Sludge Palm Oil Using Pseudomonas putida S12.

Polyhydroxyalkanoates (PHAs) are biodegradable plastics produced by bacteria, but their use in diverse applications is prohibited by high production costs. To reduce these costs, the conversion by Pseudomonas strains of P HAs from crude s ludge p alm oil ( SPO) a s an inexpensive renewable raw material was tested. Pseudomonas putida S12 was found to produce the highest yield (~41%) of elastomeric medium-chain-length (MCL)-PHAs from SPO. The MCL-PHA characteristics were analyzed by gas-chromatography/mass spectrometry, gel permeation chromatography, and differential scanning calorimetry. These findings may contribute to more widespread use of PHAs by reducing PHA production costs.