N235萃取含盐酸性废水中的盐酸

以N235为萃取剂、甲苯为稀释剂萃取模拟含盐酸性废水(简称废水)中的盐酸。最佳实验条件为:振荡时间20 min,初始废水中盐酸浓度0.75～2.45 mol/L,V(N235):V(N235+甲苯)=0.3～0.7,V(N235+甲苯):V(废水)=0.5～1.0。在初始废水中盐酸浓度为1.00 mol/L、不含无机盐、V(N235):V(N235+甲苯)=0.4、V(N235+甲苯):V(废水)=1.0的条件下,振荡20 min后萃取液中盐酸浓度为0.80 mol/L、n(盐酸):n(N235)=0.88。当废水中氯化钠浓度大于2.0 mol/L时,氯化钠的加入对N235萃取盐酸有促进作用;硫酸钠的加入对N235萃取盐酸具有抑制作用。     

Novel Environmentally Friendly Copolymers Carboxymethyl Starch Grafted Poly(Lactic Acid)

Modified natural polymers have been gaining increasing scientific interest for many years. In this study carboxymethyl starch (CMS) was grafted with L(+)-lactic acid (LA) in different molar ratios CMS/LA (1/36, 1/22 and 1/12), resulting carboxymethyl starch-g-poly(lactic acid) (CMS-g-PLA) copolymers. The grafting reaction was carried out by solution polycondensation procedure in toluene and stannous 2-ethyl hexanoate Sn(Oct)₂ as catalyst was utilized. Poly(lactic acid) (PLA) was synthesized in the same conditions with the copolymers for comparative analyses of the physico-chemical and thermal properties. The copolymers and PLA were structurally and morphologically characterized by FT-IR, ¹H-NMR spectroscopy, WAXD and SEM analyses, taking CMS as reference. The molecular weight of the copolymers, CMS and PLA were determined, using a dynamic light scattering technique. The thermal behavior of the products was studied by DSC and TG-DTG analyses. The CMS-g-PLA graft copolymers exhibited lower Tg and thermal stability than pure CMS.     

Bacterial Poly(Hydroxyalkanoate) Polymer Production from the Biodiesel Co-product Stream

A co-product stream from soy-based biodiesel production (CSBP) containing glycerol, fatty acid soaps, and residual fatty acid methyl esters (FAME) was utilized as a fermentation feedstock for the bacterial synthesis of poly(3-hydroxybutyrate) (PHB) and medium-chain-length poly(hydroxyalkanoate) (mcl-PHA) polymers. Pseudomonas oleovorans NRRL B-14682 and P. corrugata 388 grew and synthesized PHB and mcl-PHA, respectively, when cultivated in up to 5% (w/v) CSBP. In shake flask culture, P. oleovorans grew to 1.3 ± 0.1 g/L (PHA cellular productivity = 13–27% of the bacterial cell dry weight; CDW) regardless of the initial CSBP concentration, whereas P. corrugata reached maximum cell yields of 2.1 g/L at 1% CSBP, which tapered off to 1.7 g/L as the CSBP media concentration was increased to 5% (maximum PHA cellular productivity = 42% of the CDW at 3% CSBP). While P. oleovorans synthesized PHB from CSBP, P. corrugata produced mcl-PHA consisting primarily of 3-hydroxyoctanoic acid (C_8:0; 39 ± 2 mol%), 3-hydroxydecanoic acid (C_10:0; 26 ± 2 mol%) and 3-hydroxytetradecadienoic acid (C_14:2; 15 ± 1 mol%). The molar mass (M_n) of the PHB polymer decreased by 53% as the initial CSBP culture concentration was increased from 1% to 5% (w/v). In contrast, the M_n of the mcl-PHA polymer produced by P. corrugata remained constant over the range of CSBP concentrations used.     

Biodegradable Polyesters and Polyamides From Difunctionalized Lauric and Coconut Fatty Acids

In this work, a major fatty acid from coconut oil was used as starting material in preparing biodegradable polymers. Thus, polyesters and polyamides from varying proportions of monomers, hydroxy- and amino- derivatives of lauric acid were synthesized. Initially, the derivatives were prepared by regioselective chlorination of lauric acid, in the presence of ferrous ions in strong acid medium. Subsequent hydroxylation and amination procedures yielded the hydroxy- and amino- derivatives of lauric acid. These monomers were polymerized in a reaction tube by simple polycondensation method at 220–230 °C for 6–8 h without catalyst. Molecular weight determination using –COOH by end group titration and gel permeation chromatography (GPC) gave an average molar mass of 3,000–5,000 g mol⁻¹ with n = 15–25 monomer units. Thermal properties such as glass transition (T_g) and decomposition (T_d) temperatures were obtained using differential scanning calorimetry (DSC). The same processes of synthesis and determinations above were applied to coconut fatty acids, derived from saponification of coconut oil, and resulted to very similar conclusions. A quick biodegradation assay against fungus Aspergillus niger UPCC 4219 showed that the polymers prepared are more biodegradable than conventional plastics such as polypropylene, poly(ethyleneterepthalate) and poly(tetrafluoroethylene) but not as biodegradable as cellulosic (newsprint) paper.     

Poly(hydroxyalkanoate) Biosynthesis from Crude Alaskan Pollock (Theragra chalcogramma) Oil

Six strains of Pseudomonas were tested for their abilities to synthesize poly(hydroxyalkanoate) (PHA) polymers from crude Pollock oil, a large volume byproduct of the Alaskan fishing industry. All six strains were found to produce PHA polymers from hydrolyzed Pollock oil with productivities (P; the percent of the cell mass that is polymer) ranging from 6 to 53% of the cell dry weight (CDW). Two strains, P. oleovorans NRRL B-778 (P = 27%) and P. oleovorans NRRL B-14682 (P = 6%), synthesized poly(3-hydroxybutyrate) (PHB) with number average molecular weights (M_n) of 206,000 g/mol and 195,000 g/mol, respectively. Four strains, P. oleovorans NRRL B-14683 (P = 52%), P. resinovorans NRRL B-2649 (P = 53%), P. corrugata 388 (P = 43%), and P. putida KT2442 (P = 39%), synthesized medium-chain-length PHA (mcl-PHA) polymers with M_n values ranging from 84,000 g/mol to 153,000 g/mol. All mcl-PHA polymers were primarily composed of 3-hydroxyoctanoic acid (C_8:0) and 3-hydroxydecanoic acid (C_10:0) amounting to at least 75% of the total monomers present. Unsaturated monomers were also present in the mcl-PHA polymers at concentrations between 13% and 16%, providing loci for polymer derivatization and/or crosslinking. Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.     

Analysis of Products Generated from the Thermal and Catalytic Degradation of Pure and Waste Polyolefins using Py-GC/MS

The possibility of transforming waste plastics into valuable hydrocarbons via catalytic cracking and reforming is attracting increasing interest. Pyrolysis coupled with Gas Chromatographic separation and Mass Spectrometry detection (Py-GC/MS) has been used in this work to study the product selectivity of various catalysts in the conversion of pure and residual polyethylene samples into hydrocarbon products. Five acid solids of comparable aluminium contents but different textural and acid properties were tested as catalysts, including three zeolites (standard ZSM-5, nanocrystalline n-ZSM-5 and Beta) and two mesostructured solids (Al-MCM-41 and Al-SBA-15). Thermal cracking of the pure and residual polymers generated a similar range of products to each other, with a high proportion of linear paraffins and olefins of varying lengths. The presence of zeolitic materials resulted in complete elimination of heavy linear products, an increase in the light hydrocarbon fraction and a marked selectivity towards the formation of single-ring aromatic species, particularly benzene, toluene and xylene. Aromatic formation was particularly notable with the small crystal size n-ZSM-5 (aromatic selectivity up to 53.9%) and less marked in the case of standard ZSM-5 (up to 36.4%) and Beta zeolite (up to 35.0%). Mesostructured catalysts like Al-MCM-41 and Al-SBA-15 favoured the production of light C₂–C₅ hydrocarbons (up to 57.9%) while the formation of aromatic products was significantly lower than with zeolitic materials. The paper examines the extent and the causes for this product selectivity and discusses its connection with the acid and textural properties of each catalyst. It was also observed that, under the experimental conditions employed, the products generated were not significantly affected by the nature and origin of the polymers employed.     

Effect of OH/NCO Molar Ratio on Properties of Soy-Based Polyurethane Networks

Polyurethane networks from soybean oil have a number of valuable properties, which are determined by their chemical composition and cross-linking density. Changing the molar ratio of reacting groups can vary the latter. In this work we have varied the NCO/OH molar ratio (isocyanate index) from 1.05 to 0.40 in a soy polyol/MDI system, and tested physical and mechanical properties. The degree of swelling in toluene increased from 52–206% by decreasing isocyanate index from 1.05–0.4. The sol fractions and network densities determined from swelling in toluene were compared with ones obtained using the network formation theory based on branching processes. The comparison of experimental sol fractions and network densities with those predicted by theory of network formation suggest that 5–10% of bonds are lost in cycles and that high entanglement contributions increase the network densities. Polymers prepared with NCO/OH ratios from 1.05–0.8 were glassy while the others were rubbery, and that was reflected in their properties. Glass transition temperature (DSC) of the networks decreased from 64–7°C, tensile strength from 47–0.3 MPa, and elongation at break increased from 7–232%. The activation energy of the glass transition, determined from dielectric spectra, varied from 222–156 kJ/mol as the molar ratio of NCO to OH groups decreased from 1.05–0.4.     

Biodegradability: An assessment of commercial polymers according to the Canadian method for anaerobic conditions

The degradation of several biodegradable polymers was measured as a result of exposure to an anaerobic medium. The polymers investigated included materials based upon polylactic acid, polylactone, and poly(hydroxy butyrate/valerate) as well as those incorporating starch-based materials. The degradation was monitored by methane and carbon dioxide evolution. In addition, the physical and chemical changes were noted as a result of exposure. These measurements included changes in mass, dimension, and molecular weight. FTIR, UV-vis, proton, and¹³C NMR spectra were also recorded prior to and after exposure. The results clearly indicated that several biological and chemical degradation processes were occurring with the biodegradable polymers studied.Paper presented at the Bio/Environmentally Degradable Polymer Society—Second National Meeting, August 19–21, 1993, Chicago, Illinois.Issued as NRCC No. 37549.     

Chromatographic fingerprinting as a means to predict degradation mechanisms

The degradation products of polymers are identifiable by chromatography. The degradation product patterns (or fingerprints) formed depend on the type of polymer, the degradation mechanism(s), and also the type of additive present in the material. The chromatographic fingerprint of biotically aged degradable low-density polyethylene (i.e., LDPE+starch+prooxidant) shows, in particular, the absence of low molecular weight carboxylic acids, which suggests an assimilation of these carboxylic acids by the microorganisms. The degradation products of natural polymers are usually intermediates that are used again in the anabolic cycles. It is possible to transfer the terminology from the natural polymers, where the catabolism of natural polymers consists of three stages, and apply this also to the degradable synthetic polymers. During stage I the natural polymers degrade to their major building blocks (e.g., amino acids, glycerol, hexoses, pentoses, etc.), during stage II these products are collected and converted to a smaller number of even simpler molecules [e.g., acetyl-coenzyme A (CoA)]. In stage III, finally, the acetyl-CoA enters the citric acid cycle, where energy is gained in parallel with the release of CO₂ and H₂O.Presented at the international workshop,Polymers from Renewable Resources and their Degradation, Stockholm, Sweden, November 10–11, 1994.     

Effect of Bimetallic Soybean Oil Based Polymer on Growth and Plasma Membrane H+-ATPase Activity Among Fungi

In view of bio-inorganic importance, iron and zinc incorporated soybean oil based polymer was prepared by condensation polymerization of oil based fatty amide polyole, sebacic acid, zinc acetate and ferric chloride in a process initiated by sodium ethoxide. Microwave assisted synthesis was used throughout the reaction as it is ecofriendly and requires minimal usage of solvents. Physical techniques such as FT-IR and ¹HNMR have been used to establish the structure of the polymers. Standard laboratory methods like acid value, saponification value, iodine value, specific gravity and viscosity were used to study the chemical diversity of each product. Thermo gravimetry/differential thermal analyzer was used to analyse the thermal behavior of polymer. The synthesized compounds were subjected to biological study. The observed fungicidal characteristics of synthesized compounds indicate that these compounds might be promising antifungal agents defining a new class of antimycotics. The polymers were used in preparation of films which can be used as protective packaging material of edible items.     

From Natural Oils to Epoxy Resins: A New Paradigm in Renewable Performance Materials

The direct conversion of natural products to useful engineering materials is desirable from both economic and environmental considerations. We describe the synthesis and properties of 100?% oil-based epoxy resins generated from three epoxidized oils. The catalyst, tris(pentafluorophenyl)borane (B(C₆F₅)₃) in toluene, allowed for controlled cationic polymerization at a very low concentration. Epoxidized oils (derived from triolein, soybean, and linseed oil) had varying epoxy content, rendering resins of different cross-link density. The polymerization was carried out at room temperature followed by post-curing at elevated temperature to speed up conversion. Epoxy resins were amorphous transparent glasses below glass transitions and hard rubbers above. Despite their high cross-link density, these materials show relatively low T_g’s reflecting the aliphatic nature of fatty acids and the presence of plasticizing “dangling” chains. The structure of the triglyceride starting oils influenced the properties of the resulting materials: the more regular structure of triolein compared to the very heterogeneous structures of soybean and linseed oils seemed to have enhanced some properties of the polymer networks. These epoxy polymers are potentially useful as encapsulating and potting compounds for electronic applications.

     

利用磷霉素生产盐渣合成阻垢剂

将磷霉素生产盐渣经水解得到右旋磷霉素二钠,再通过亲核取代反应得到可用作循环冷却水阻垢剂的氨基二乙基(1-甲基-2-羟基)膦酸四钠(ADMHP·Na4),并用FTIR表征了产物结构.实验结果表明:在取代反应温度为25℃、取代反应时间为2h、n(氨水)∶n(右旋磷霉素二钠)=8的条件下,由右旋磷霉素二钠制备ADMHP·Na4,收率可达83.87％.处理1t盐渣可创造利润3 080元.当ADMHP·Na4质量浓度为30 mg/L,水样温度为60℃时,ADMHP·Na4对CaCO3的阻垢效果较好,阻垢率可达91.47％.     

Changes in organic matter composition during composting of two digested sewage sludges

Changes in the chemical and chemical-structural composition of the organic matter of two different sewage sludges (aerobic and anaerobic) mixed with sawdust (1:1 and 1:3, v/v) during composting were determined by monitoring chemical and microbiological parameters as well as by pyrolysis-gas chromatography. Composting was carried out in periodically turned outdoor piles, which were sampled for analysis 1, 30, 60 and 90 days after the beginning of the composting process. Both volatile organic matter and the water soluble C fraction decreased during composting, indicating that the more labile C fractions are mineralized during the process. Microbial activity as measured by microbial respiration (CO(2) evolved from compost samples during incubation) also decreased with composting, reflecting the more stable character of the resulting compost. No major differences were observed between the four composts studied as regards their chemical-structural characteristics. The acetonitrile, acetic acid and phenol pyrolytic fragment tended to increase with composting. Although the final composts were more aromatic in nature than the starting materials, a low degree of humification was observed in all four composts studied, as determined by their high proportion of polysaccharides and alkyl compounds. For this reason, the relationship between pyrolytic fragments, such as benzene/toluene or benzene+toluene/pyrrol+phenols, which are used as indices of humification for soil organic matter, are not of use for such poorly evolved sludge composts; instead, ratios that involve carbohydrate derivatives and aromatic compounds, such as furfural+acetic/benzene+toluene or acetic/toluene, are more sensitive indices for reflecting the transformations of these materials during composting. Both the chemical and microbiological parameters and pyrolytic analysis provided valuable information concerning the nature of the compost's organic matter and its changes during the composting process.     

An overview of methods for biodegradability testing of biopolymers and packaging materials

This paper gives an overview of the methods used at the Technical Research Centre of Finland (VTT) for the biodegradability testing of solid polymers and packaging materials. Biodegradability of each polymer included in the packaging material should be separately tested. Aquatic aerobic and anaerobic tests and, in specific cases, enzymatic tests are used for screening purposes. The application of aquatic aerobic tests—an automated Sturm test (OECD 301B; ASTM D5209) and a VTT headspace test as well as an anaerobic test (ASTM D5210)—is discussed. Three composting tests and their applications are summarized. These tests are regarded as important because they can be used to simulate the biodegradability under real-life conditions. Several tests are needed to determine the fate of the polymer under real conditions and to study its biodegradability in different environments. The time needed for complete biodegradation of polymers in nature is impossible to predict with laboratory tests and should be studiedin vivo.According to the lecture given in Sweden at the Royal Institute of Technology, at a workshop on polymers from renewable resources and their degradation, November 10–11, 1994.     

Controlling the Behaviors of Biodegradable/Bioabsorbable Polymers with Cyclodextrins

The cyclic six, seven, and eight-membered oligosaccharides -, -, and -cyclodextrins (CDs) can serve as hosts for a variety of polymer guests to form crystalline inclusion compounds (ICs), wherein the guest polymers are included in the continuous narrow channels (0.5–1.0 nm in diameter) formed by the host CD stacks. Polymers included as guests in CD-ICs are highly extended and segregated from neighboring chains by the walls of the host CD bracelets. As a consequence, when polymer-CD-ICs are treated with solvents for CDs that are non-solvents for the included polymers or with amylase enzymes, the CDs are removed and the guest polymers are coalesced into bulk samples whose structures, morphologies, and even chain conformations are different from those achieved by consolidation from their randomly coiling, entangled solutions and melts. Often these CD-IC coalesced and consequently reorganized polymer samples exhibit properties that are distinct from their normally processed bulk samples. Here we describe the CD-IC processing of several biodegradable/bioabsorbable homopolymers, copolymers, and blends made from poly (L-lactic acid), poly (-caprolactone), and poly (-hydroxybutyrate)s, with special emphasis placed on their improved and controllable properties. For example, the phase segregation and consequent crystallinities of their normally incompatible homopolymer blends and their block copolymers may be controlled and thus improved. In addition, co-inclusion of small molecule guests, such as drugs or anti-bacterials, in their common CD-ICs, and subsequent coalescence, yields well-mixed blends of these biodegradable/bioabsorbable polymers and the small molecule co-guests, which may lead, for example, to the improved delivery of drugs.     

Construction, Characterization and Biological Activity of Chiral and Thermally Stable Nanostructured Poly(Ester-Imide)s as Tyrosine-Containing Pseudo-Poly(Amino Acid)s

In this paper we studied the synthesis of biodegradable optically active poly(ester-imide)s containing different amino acid residues in the main chain. These pseudo-poly(amino acid)s were synthesized by polycondensation of N,N′-(pyromellitoyl)-bis-l-tyrosine dimethyl ester as a diphenolic monomer and two chiral trimellitic anhydride-derived diacid monomers containing s-valine and l-methionine. The direct polycondensation reaction of these diacids with aromatic diol was carried out in a system of tosyl chloride (TsCl), pyridine (Py) and N,N′-dimethylformamide (DMF) as a condensing agent. The structures and morphology of these polymers were studied by FT-IR, ¹H-NMR, powder X-ray diffraction, field emission scanning electron microscopy (FE-SEM), specific rotation, elemental and thermogravimetric analysis (TGA) techniques. TGA profiles indicate that the resulting PEIs have a good thermal stability. Morphology probes showed these polymers were noncrystalline and nanostructured polymers. The monomers and prepared polymers were buried under the soil to study the sensitivity of the monomers and the obtained polymers to microbial degradation. The high microbial population and prominent dehydrogenase activity in the soil containing polymers showed that the synthesized polymers are biologically active and microbiologically biodegradable. Wheat seedling growth in the soil buried with synthetic polymers not only confirmed non-toxicity of polymers but also showed possibility of phyto-remediation in polymer-contaminated soils.     

Poly(Lactic Acid)-co-Aspartic Acid Copolymers: Possible Utilization in Drug Delivery Systems

The synthesis and characterization of poly(lactic acid)-co-aspartic acid copolymers (PLA-co-Asp) were presented. Subsequently, the synthesized PLA-co-Asp copolymers were tested as biodegradable carriers in drug delivery systems. PLA-co-Asp copolymers were synthesized by solution polycondensation procedure, using different molar ratios PLA/l-aspartic acid (2.33/1, 1/1, 1/2.33), manganese acetate and phosphoric acid as catalysts and N,N′-dimethyl formamide (DMF)/toluene as solvent mixture. The copolymers were characterized by FT-IR and ¹H-NMR spectroscopy, gel permeation chromatography (GPC), DSC and TG-DTG analyses. Diclofenac sodium, a non steroidal anti-inflammatory drug was subsequently loaded into PLA-co-Asp copolymers. The in vitro drug release experiments were done by dialysis of the copolymer/drug systems, in phosphate buffer solution (pH = 7.4, at 37 °C) and monitored by UV spectroscopy.     

Poly(vinyl alcohol-co-lactic acid)/Hydroxyapatite Composites: Synthesis and Characterization

There is a wide range of applications where calcium phosphate and hydroxyapatite (HA) are used as biomaterials, e.g. as synthetic bone grafts, coating on metal prostheses (like hip endoprostheses or dental implants) and drug carriers. In the study, the design and synthesis of composites based on poly(vinyl alcohol-co-lactic acid)/hydroxyapatite (PVA-co-LA/HA) with potential for biomedical applications, they are presented. The hydroxyapatite particles were surface-grafted with l(+)-lactic acid in the presence of manganese acetate as catalyst, resulting in modified hydroxyapatite (HA_m) with improved capacity of bonding, respectively for the preparation of the composite based on PVA-co-LA/HA_m. FT-IR spectra further confirmed the existence of PLA polymer on the surface of HA particles. In synthesis of PVA-co-LA copolymer the different molar ratios PVA/LA (2/1, 1/1, 1/2), toluene/water: 1/2 (as azeotrope solvent mixture) and manganese acetate as catalyst, were used. The composite materials were synthesized in situ with 10 wt% HA, and respectively HA_m (reported to PVA and lactic acid components). The composite materials were characterized by FTIR spectroscopy, thermal analyses (DSC, DTG), ¹H-NMR spectroscopy, particle size distribution and zeta potential.     

Structural Differences Between Lignin Model Polymers Synthesized from Various Monomers

In a plant cell wall, lignin is synthesized from several monomeric precursors, combined in various ratios. The variation in monomer type and quantity enables multifunctional role of lignin in plants. Thus, it is important to know how different combinations of lignin monomers impact variability of bond types and local structural changes in the polymer. Lignin model polymers are a good model system for studies of relation between variations of the starting monomers and structural variations within the polymer. We synthesized lignin model polymers from three monomers, CF??based on coniferyl alcohol and ferulic acid in monomer proportions 5:1 and 10:1 (w/w), CP??based on coniferyl alcohol and p-coumaric acid in proportion 10:1 (w/w) and CA??based on pure coniferyl alcohol. We studied structural modifications in the obtained polymers, by combining fluorescence microscopy and spectroscopy, FT-IR and Raman spectroscopy, in parallel with determination of polymers?? molecular mass distribution. The differences in the low M _w region of the distribution curves of the 10:1 polymers in comparison with the CA polymer may be connected with the increased content of C=C bonds and decreased content of condensed structures, as observed in FT-IR spectra and indicated by the analysis of fluorescence spectra. The 5:1 CF polymer contains a different type of structure in comparison with the 10:1 CF polymers, reflected in its simpler M _w distribution, higher homogeneity of the fluorescence emitting structures and in the appearance of a new high-wavelength emission component. We propose that this component may originate from ??-conjugated chains, which are longer in this polymer. The results are a contribution to the understanding of the involvement of structural variations of lignin polymers in the cell wall structural plasticity.     

Production of Poly(3-hydroxyalkanoate)s by Pseudomonas putida Cultivated in a Glycerol/Nonanoic Acid-Containing Medium

The biosynthesis of poly(3-hydroxyalkanoate) (PHA) by Pseudomonas putida (JCM6160) cultivated in a medium containing glycerol, nonanoic acid, or a glycerol/nonanoic acid mixture as the sole carbon sources was investigated. The PHA content was ~20 % when glycerol was the carbon source. This relatively low content can be attributed to the glycerol end-cap effect and the absence of enzymes that can directly synthesize PHA from acetyl CoA, which is the major metabolite of glycerol. Fatty acids, containing even numbered carbons, are synthesized from acetyl CoA, and they can be used as substrates for PHA synthesis. However, this process also results in decreasing PHA content as fatty acids are siphoned off into other pathways. However, addition of 5 mM nonanoic acid into a 20 mM glycerol-containing medium dramatically increased the PHA content in P. putida, which was 1.3 times larger than the sum of the values found when glycerol and nonanoic acid were each used as the sole carbon source. The PHA, synthesized in the glycerol/nonanoic acid medium, contains 3-hydroxy alkanoate units that have 5, 6, 7, 8, 9, or 10 carbons. The units that contain the even numbered carbons are derived from fatty acids that were produced from glycerol; whereas, the PHA units with the odd numbered carbons are derived from nonanoic acid. Pentanoate units were also found in the polyester derived from glycerol and nonanoic acid, and must have been synthesized indirectly via β-oxidation of nonanoic acid with the assistance of glycerol because pentanoate units were not found in PHA when P. putida was cultivated in the presence of only nonanoic acid.