Giuseppe Impallomeni | Consiglio Nazionale delle Ricerche (CNR) (original) (raw)
Papers by Giuseppe Impallomeni
Carbohydrate Research, 1995
Pseudomonas aeruginosa Brassica carinata oil ESI mass spectrometry NMR Biodegradable polymers a b... more Pseudomonas aeruginosa Brassica carinata oil ESI mass spectrometry NMR Biodegradable polymers a b s t r a c t Pseudomonas aeruginosa produced medium chain length poly(3-hydroxyalkanoates) (mcl-PHAs) when grown on substrates containing very long chain fatty acids (VLCFA, C > 20). Looking for low cost carbon sources, we tested Brassica carinata oil (erucic acid content 35–48%) as an intact triglyceride containing VLCFA. Oleic (C 18:1), erucic (C 22:1), and nervonic (C 24:1) acids were also employed for mcl-PHA production as model substrates. The polymers obtained were analyzed by GC of methanolyzed samples, GPC, 1 H and 13 C NMR, ESI MS of partially pyrolyzed samples, and DSC. The repeating units of such polymers were saturated and unsaturated, with a higher content of the latter in the case of the PHA obtained from B. carinata oil. Statistical analysis of the ion intensity in the ESI mass spectra showed that the PHAs from pure fatty acids are random copolymers, while the PHA from B. carinata oil is either a pure polymer or a mixture of polymers. Weight-average molecular weight varied from ca. 56,000 g/mol for the PHA from B. carinata oil and oleic acid, to about 120,000 g/mol for those from erucic and nervonic acids. The PHAs from erucic and nervonic acids were partially crystalline, with rubbery characteristics and a melting point (T m) of 50 • C, while the PHAs from oleic acid and from B. carinata oil afforded totally amorphous materials, with glass transition temperatures (T g) of −52 • C and −47 • C, respectively.
Very long chain fatty acids (VLCFA), longer than C20, were employed for the production of medium ... more Very long chain fatty acids (VLCFA), longer than C20, were
employed for the production of medium chain length poly(3-
hydroxyalkanoates) (mcl-PHA) by Pseudomonas aeruginosa. In
order to keep the production costs low, Brassica carinata oil (erucic acid average content 35 - 48%) was employed as the intact triglyceride containing VLCFA. As free fatty acids erucic acid (C22:1) and nervonic acid (C24:1) were employed.
Weight average molecular weight, determined by GPC, varied
from 56000 for PHA from B. carinata oil to about 120000 for those from erucic and nervonic acids. Monomeric units composition was obtained by GC analysis while the structural characterization was performed by 1H- and 13C-NMR. The 3-hydroxyacids making up the repeating units of such polymers were saturated and unsaturated, with a higher content of the latter in the case of PHAs obtained from
B. carinata oil. ESI MS of partially pyrolysed samples allowed the identification of oligomers up to heptamers and statistical analysis of the ion intensity in the mass spectra showed that these PHAs are random copolymers.
The PHAs from erucic and nervonic acids were partially crystalline, with rubbery characteristics and a melting point (Tm) of 50 ◦C, while the increase of unsaturation degree in the repeating units of PHA from B. carinata oil afforded a totally amorphous material, with a glass transition temperature (Tg) of -47 ◦C.
Carbohydrate Research, 2005
The bacterial species Enterobacter amnigenus was isolated from sugar beets harvested in Finland. ... more The bacterial species Enterobacter amnigenus was isolated from sugar beets harvested in Finland. It produced an exopolysaccharide rich in L L-fucose, which gave viscous water solutions. Its primary structure was determined mainly by NMR spectroscopy and ESIMS of oligosaccharides and a polysaccharide with decreased molecular weight, obtained by Smith degradation of the Odeacetylated native polymer.
Biomacromolecules, 2004
Pseudomonas aeruginosa ATCC 27853 accumulated poly(3-hydroxyalkanoates) (PHAs) after growth on sa... more Pseudomonas aeruginosa ATCC 27853 accumulated poly(3-hydroxyalkanoates) (PHAs) after growth on saturated fatty acids with an odd number of carbon atoms. No nutrient limitation was required to induce PHA synthesis, although better yields were obtained when the medium was magnesium deprived. A comparative study was carried out between PHAs obtained from C-odd and those from C-even carbon sources. Repeating units identification was performed by gas chromatography (GC) and capillary liquid chromatography-electrospray mass spectrometry (LC-ESI MS) of methanolyzed samples. When C-odd n-alkanoic acids from nonanoic to pentadecanoic were used the lowest hydroxyalkanoate unit found was 3-hydroxyvalerate and the highest 3-hydroxypentadecanoate, whereas when C-even acids from octanoic to eicosanoic were used these were 3-hydroxycaproate and 3-hydroxyeicosanoate, respectively. Weight average molecular weights were in the range 187 000-596 000. DSC traces showed Tm and DeltaHm which varied from 43 to 58 degrees C and from 5.9 to 24.8 J/g, with the PHAs generated from C-odd carbon sources having lower values. ESI MS of partially pyrolyzed samples allowed the identification of oligomers up to heptamers, and statistical analysis of the ions intensity in the mass spectra showed that these PHAs are random copolyesters.
Journal of Biotechnology, 2010
International Journal of Biological Macromolecules, 2011
Pseudomonas aeruginosa produced medium chain length poly(3-hydroxyalkanoates) (mcl-PHAs) when gro... more Pseudomonas aeruginosa produced medium chain length poly(3-hydroxyalkanoates) (mcl-PHAs) when grown on substrates containing very long chain fatty acids (VLCFA, C > 20). Looking for low cost carbon sources, we tested Brassica carinata oil (erucic acid content 35-48%) as an intact triglyceride containing VLCFA. Oleic (C 18:1 ), erucic (C 22:1 ), and nervonic (C 24:1 ) acids were also employed for mcl-PHA production as model substrates. The polymers obtained were analyzed by GC of methanolyzed samples, GPC, 1 H and 13 C NMR, ESI MS of partially pyrolyzed samples, and DSC. The repeating units of such polymers were saturated and unsaturated, with a higher content of the latter in the case of the PHA obtained from B. carinata oil. Statistical analysis of the ion intensity in the ESI mass spectra showed that the PHAs from pure fatty acids are random copolymers, while the PHA from B. carinata oil is either a pure polymer or a mixture of polymers. Weight-average molecular weight varied from ca. 56,000 g/mol for the PHA from B. carinata oil and oleic acid, to about 120,000 g/mol for those from erucic and nervonic acids. The PHAs from erucic and nervonic acids were partially crystalline, with rubbery characteristics and a melting point (T m ) of 50 • C, while the PHAs from oleic acid and from B. carinata oil afforded totally amorphous materials, with glass transition temperatures (T g ) of −52 • C and −47 • C, respectively.
The ability of Pseudomonas aeruginosa ATCC 27853 to grow and synthesize polyhydroxyalkanoates (PH... more The ability of Pseudomonas aeruginosa ATCC 27853 to grow and synthesize polyhydroxyalkanoates (PHAs) using Tween 20 as the sole carbon source was investigated. Tween 20 could support cell growth and PHA production. The polymer produced from Tween 20 was compared with those produced from its major free fatty acids components: lauric (C12), myristic (C14), and palmitic (C16) acids. Gas-chromatographic analysis
International Journal of Biological Macromolecules, 2001
In this study, we investigated the ability of Pseudomonas aeruginosa ATCC 27853 to grow and synth... more In this study, we investigated the ability of Pseudomonas aeruginosa ATCC 27853 to grow and synthesize poly(3-hydroxyalkanoates) (PHAs) from saturated fatty acids with an even number of carbon atoms, from eight to 22, and from oleic acid. In a non-limiting medium, all carbon sources but docosanoic acid supported cell growth and PHA production, with eicosanoic acid giving the highest yield. In magnesium-limiting conditions, higher yields were obtained from sources with up to 16 carbon atoms. Composition was estimated by gas chromatography of methanolyzed samples and 13 C nuclear magnetic resonance. The 3-hydroxyalkanoate units extended from hexanoate to tetradecanoate or tetradecenoate, with octanoate and decanoate as the predominant components. Weight average molecular weights ranged from 78 000 to 316 000. Fast atom bombardment mass spectrometry of partially pyrolyzed samples, coupled to statistical analysis, showed that these PHAs are random copolymers.
International Journal of Biological Macromolecules, 2000
The exopolysaccharide produced by a cystic fibrosis clinical isolate of Agrobacterium radiobacter... more The exopolysaccharide produced by a cystic fibrosis clinical isolate of Agrobacterium radiobacter was shown by monosaccharide and methylation analyses, degradation with succinoglycanase and NMR analysis to be a succinoglycan with the structure shown below. (S)-pyruvic acid is found stoichiometrically as 4,6-O-ketal substituent of terminal glucose. Succinic acid is present in 40% of the repeating units and it is attached to O-6 of the 3-linked glucose next to the pyruvate carrying sugar. Some evidence is found that a small amount of succinic acid (ca. 6% of the total) is linked to O-6 of another undetermined glucose.
Carbohydrate Research, 1991
A new oligosaccharide subunit of xyloglucan was isolated from the beta-(1----4)-endoglucanase dig... more A new oligosaccharide subunit of xyloglucan was isolated from the beta-(1----4)-endoglucanase digestion products of the xyloglucan in what is referred to as "sycamore extracellular polysaccharides" and found to be an undecasaccharide having two terminal alpha-L-fucopyranosyl residues. The undecasaccharide was structurally characterized by 1H-n.m.r. spectroscopy, fast-atom bombardment mass spectrometry (f.a.b.-m.s.), and glycosyl-residue and glycosyl-linkage composition analyses. The structure of the undecasaccharide was confirmed by digesting it with a hydrolase that releases alpha-D-Xylp-(1----6)-D-Glc from the non-reducing end of xyloglucan oligosaccharides.
Biomacromolecules, 2007
Copolymers of 3-hydroxybutyrate (3HB) and 3-mercaptopropionate (3MP) or 3-mercaptobutyrate (3MB) ... more Copolymers of 3-hydroxybutyrate (3HB) and 3-mercaptopropionate (3MP) or 3-mercaptobutyrate (3MB) units and minor amounts of 3-hydroxypropionate (3HP), 3-hydroxyvalerate (3HV), or 3-mercaptovalerate (3MV) were investigated regarding their microstructure by NMR, electrospray ionization mass spectrometry, and size exclusion chromatography NMR. These copolymers were produced by Ralstonia eutropha strain H16 when cells were cultivated in a mineral salts medium with gluconate as a carbon source for growth and 3MP or 3MB as precursor substrates for incorporation of 3-mercaptoalkanoates. Mass spectrometry analysis of partially methanolyzed or pyrolyzed samples proved the presence of true copolymers or terpolymers. (13)C NMR spectroscopy of intact polymer samples, with values of average block length and degree of randomness deviating from a random sequence model, suggested microblock structures; however, composition analysis by (1)H NMR of fractions obtained by size exclusion chromatography showed significant variations with molecular weight, revealing the presence of blends of poly(3HB-co-3MP-co-3HP) or poly(3HB-co-3MB) with poly(3HB). The experimental NMR carbonyl dyad signal intensities were satisfactorily matched by a random sequence model when the presence of poly(3HB) was taken into account.
Polymer Degradation and Stability, 1988
... Alberto Ballistreri,a Domenico Garozzo," Mario Giuffrida,b Giuseppe ... more ... Alberto Ballistreri,a Domenico Garozzo," Mario Giuffrida,b Giuseppe Impallomenia Giorgio Montaudoa a Dipartimento di Scienze Chimiche, Universita di Catania, b Istituto per la Chimica e la Tecnologia dei Materiali Polimerici, Consiglio Nazionale delle Ricerche, Viale Andrea ...
Polymer Degradation and Stability, 1989
... Scaiano, J. C.; Tanner, M.; Weir, D. J. Am. ... Domenico Garozzo,t Mario Giuffrida,t and Gior... more ... Scaiano, J. C.; Tanner, M.; Weir, D. J. Am. ... Domenico Garozzo,t Mario Giuffrida,t and Giorgio Montaudo*t Dipartimento di Scienze Chimiche, Uniuersitd di Catania, 95125 Catania, Italy, and Istituto per la Chimica e la Tecnologia dei Materiali Polimerici, Consiglio Nazionale delle ...
European Journal of Pharmaceutical Sciences, 2009
Poly(3-hydroxybutyrate-co-ε-caprolactone) copolymers and poly(3-hydroxybutyrate-co-3hydroxyvalera... more Poly(3-hydroxybutyrate-co-ε-caprolactone) copolymers and poly(3-hydroxybutyrate-co-3hydroxyvalerate-co--caprolactone) terpolymers were used by a solvent deposition technique to prepare either micro-or nanoparticles. In particular, the synthesis and analytical characterization of the terpolymers were described.
Carbohydrate Polymers, 2007
A study of the interaction among sodium alginates of diVerent molecular compositions, water and g... more A study of the interaction among sodium alginates of diVerent molecular compositions, water and glycerol was carried out, in order to weigh up the inXuence of diVerent polymeric microstructures on the chemical-physical properties of Wlms obtained by water soluble blends of sodium alginates and increasing amounts of glycerol. Thermal, mechanical and morphological analyses performed on the Wlms conWrmed the existence of speciWc interactions between sodium alginates and glycerol; it was as well demonstrated that only at speciWc mass ratio between the single polymers and glycerol it is possible to obtain the correct plasticizing eVect induced by glycerol.
Macromolecules, 1990
Two different samples of copolyesters produced by Pseudomonas oleouorans when grown either on non... more Two different samples of copolyesters produced by Pseudomonas oleouorans when grown either on nonanoic acid alone or on an equimolar mixture of nonanoic and octanoic acids were evaluated for sequence distribution by controlled methanolysis to their oligomers, separation of the oligomers by HPLC, and analysis of the fractions so obtained by fast atom bombardment mass spectrometry (FAB-MS). The copolyesters contained primarily 0-hydroxyheptanoate and 0-hydroxynonanoate units, which showed no observable differences in their l H and *3C NMR spectra with changes in composition, so those analyses could not be applied. The observed oligomer composition and that calculated on the basis of Bernoullian statistics for sequence distributions in random copolymers of the compositions studied were in good agreement.
Macromolecules, 1995
Stevioside is a non-cariogenic and low-calorigenic diterpenoid glycoside has slightly bitterness ... more Stevioside is a non-cariogenic and low-calorigenic diterpenoid glycoside has slightly bitterness and bad after taste. Enzymatic modification by alternansucrase from Leuconostoc citreum SK24.002 was utilized in biotransformation of stevioside to remove the bitter taste fully or partially and an aftertaste of the stevioside, using sucrose as donor and stevioside as acceptor. Tri-glucosyl-stevioside produced during alternansucrase acceptor reaction of stevioside were successfully separated using adsorption separation technology of macroporous adsorption resin (AB-8) flowed by semipreparative high performance liquid chromatography. Structure of the product was characterized to be 13-{[α-D-glucopyranosyl-(1→3)-α-D-glucopyranosyl-(1→6)-α-D-glucopyranosyl-(1→3)-β-Dglucopyranosyl-(1→2)-β-D-glucopyranosyl]oxy}kaur-16-en-19-oic acid β-D glucopyranosyl ester on the basis of extensive one dimension and two dimensional NMR and LC-ESI-MS in negative mode data.
Carbohydrate Research, 1995
Pseudomonas aeruginosa Brassica carinata oil ESI mass spectrometry NMR Biodegradable polymers a b... more Pseudomonas aeruginosa Brassica carinata oil ESI mass spectrometry NMR Biodegradable polymers a b s t r a c t Pseudomonas aeruginosa produced medium chain length poly(3-hydroxyalkanoates) (mcl-PHAs) when grown on substrates containing very long chain fatty acids (VLCFA, C > 20). Looking for low cost carbon sources, we tested Brassica carinata oil (erucic acid content 35–48%) as an intact triglyceride containing VLCFA. Oleic (C 18:1), erucic (C 22:1), and nervonic (C 24:1) acids were also employed for mcl-PHA production as model substrates. The polymers obtained were analyzed by GC of methanolyzed samples, GPC, 1 H and 13 C NMR, ESI MS of partially pyrolyzed samples, and DSC. The repeating units of such polymers were saturated and unsaturated, with a higher content of the latter in the case of the PHA obtained from B. carinata oil. Statistical analysis of the ion intensity in the ESI mass spectra showed that the PHAs from pure fatty acids are random copolymers, while the PHA from B. carinata oil is either a pure polymer or a mixture of polymers. Weight-average molecular weight varied from ca. 56,000 g/mol for the PHA from B. carinata oil and oleic acid, to about 120,000 g/mol for those from erucic and nervonic acids. The PHAs from erucic and nervonic acids were partially crystalline, with rubbery characteristics and a melting point (T m) of 50 • C, while the PHAs from oleic acid and from B. carinata oil afforded totally amorphous materials, with glass transition temperatures (T g) of −52 • C and −47 • C, respectively.
Very long chain fatty acids (VLCFA), longer than C20, were employed for the production of medium ... more Very long chain fatty acids (VLCFA), longer than C20, were
employed for the production of medium chain length poly(3-
hydroxyalkanoates) (mcl-PHA) by Pseudomonas aeruginosa. In
order to keep the production costs low, Brassica carinata oil (erucic acid average content 35 - 48%) was employed as the intact triglyceride containing VLCFA. As free fatty acids erucic acid (C22:1) and nervonic acid (C24:1) were employed.
Weight average molecular weight, determined by GPC, varied
from 56000 for PHA from B. carinata oil to about 120000 for those from erucic and nervonic acids. Monomeric units composition was obtained by GC analysis while the structural characterization was performed by 1H- and 13C-NMR. The 3-hydroxyacids making up the repeating units of such polymers were saturated and unsaturated, with a higher content of the latter in the case of PHAs obtained from
B. carinata oil. ESI MS of partially pyrolysed samples allowed the identification of oligomers up to heptamers and statistical analysis of the ion intensity in the mass spectra showed that these PHAs are random copolymers.
The PHAs from erucic and nervonic acids were partially crystalline, with rubbery characteristics and a melting point (Tm) of 50 ◦C, while the increase of unsaturation degree in the repeating units of PHA from B. carinata oil afforded a totally amorphous material, with a glass transition temperature (Tg) of -47 ◦C.
Carbohydrate Research, 2005
The bacterial species Enterobacter amnigenus was isolated from sugar beets harvested in Finland. ... more The bacterial species Enterobacter amnigenus was isolated from sugar beets harvested in Finland. It produced an exopolysaccharide rich in L L-fucose, which gave viscous water solutions. Its primary structure was determined mainly by NMR spectroscopy and ESIMS of oligosaccharides and a polysaccharide with decreased molecular weight, obtained by Smith degradation of the Odeacetylated native polymer.
Biomacromolecules, 2004
Pseudomonas aeruginosa ATCC 27853 accumulated poly(3-hydroxyalkanoates) (PHAs) after growth on sa... more Pseudomonas aeruginosa ATCC 27853 accumulated poly(3-hydroxyalkanoates) (PHAs) after growth on saturated fatty acids with an odd number of carbon atoms. No nutrient limitation was required to induce PHA synthesis, although better yields were obtained when the medium was magnesium deprived. A comparative study was carried out between PHAs obtained from C-odd and those from C-even carbon sources. Repeating units identification was performed by gas chromatography (GC) and capillary liquid chromatography-electrospray mass spectrometry (LC-ESI MS) of methanolyzed samples. When C-odd n-alkanoic acids from nonanoic to pentadecanoic were used the lowest hydroxyalkanoate unit found was 3-hydroxyvalerate and the highest 3-hydroxypentadecanoate, whereas when C-even acids from octanoic to eicosanoic were used these were 3-hydroxycaproate and 3-hydroxyeicosanoate, respectively. Weight average molecular weights were in the range 187 000-596 000. DSC traces showed Tm and DeltaHm which varied from 43 to 58 degrees C and from 5.9 to 24.8 J/g, with the PHAs generated from C-odd carbon sources having lower values. ESI MS of partially pyrolyzed samples allowed the identification of oligomers up to heptamers, and statistical analysis of the ions intensity in the mass spectra showed that these PHAs are random copolyesters.
Journal of Biotechnology, 2010
International Journal of Biological Macromolecules, 2011
Pseudomonas aeruginosa produced medium chain length poly(3-hydroxyalkanoates) (mcl-PHAs) when gro... more Pseudomonas aeruginosa produced medium chain length poly(3-hydroxyalkanoates) (mcl-PHAs) when grown on substrates containing very long chain fatty acids (VLCFA, C > 20). Looking for low cost carbon sources, we tested Brassica carinata oil (erucic acid content 35-48%) as an intact triglyceride containing VLCFA. Oleic (C 18:1 ), erucic (C 22:1 ), and nervonic (C 24:1 ) acids were also employed for mcl-PHA production as model substrates. The polymers obtained were analyzed by GC of methanolyzed samples, GPC, 1 H and 13 C NMR, ESI MS of partially pyrolyzed samples, and DSC. The repeating units of such polymers were saturated and unsaturated, with a higher content of the latter in the case of the PHA obtained from B. carinata oil. Statistical analysis of the ion intensity in the ESI mass spectra showed that the PHAs from pure fatty acids are random copolymers, while the PHA from B. carinata oil is either a pure polymer or a mixture of polymers. Weight-average molecular weight varied from ca. 56,000 g/mol for the PHA from B. carinata oil and oleic acid, to about 120,000 g/mol for those from erucic and nervonic acids. The PHAs from erucic and nervonic acids were partially crystalline, with rubbery characteristics and a melting point (T m ) of 50 • C, while the PHAs from oleic acid and from B. carinata oil afforded totally amorphous materials, with glass transition temperatures (T g ) of −52 • C and −47 • C, respectively.
The ability of Pseudomonas aeruginosa ATCC 27853 to grow and synthesize polyhydroxyalkanoates (PH... more The ability of Pseudomonas aeruginosa ATCC 27853 to grow and synthesize polyhydroxyalkanoates (PHAs) using Tween 20 as the sole carbon source was investigated. Tween 20 could support cell growth and PHA production. The polymer produced from Tween 20 was compared with those produced from its major free fatty acids components: lauric (C12), myristic (C14), and palmitic (C16) acids. Gas-chromatographic analysis
International Journal of Biological Macromolecules, 2001
In this study, we investigated the ability of Pseudomonas aeruginosa ATCC 27853 to grow and synth... more In this study, we investigated the ability of Pseudomonas aeruginosa ATCC 27853 to grow and synthesize poly(3-hydroxyalkanoates) (PHAs) from saturated fatty acids with an even number of carbon atoms, from eight to 22, and from oleic acid. In a non-limiting medium, all carbon sources but docosanoic acid supported cell growth and PHA production, with eicosanoic acid giving the highest yield. In magnesium-limiting conditions, higher yields were obtained from sources with up to 16 carbon atoms. Composition was estimated by gas chromatography of methanolyzed samples and 13 C nuclear magnetic resonance. The 3-hydroxyalkanoate units extended from hexanoate to tetradecanoate or tetradecenoate, with octanoate and decanoate as the predominant components. Weight average molecular weights ranged from 78 000 to 316 000. Fast atom bombardment mass spectrometry of partially pyrolyzed samples, coupled to statistical analysis, showed that these PHAs are random copolymers.
International Journal of Biological Macromolecules, 2000
The exopolysaccharide produced by a cystic fibrosis clinical isolate of Agrobacterium radiobacter... more The exopolysaccharide produced by a cystic fibrosis clinical isolate of Agrobacterium radiobacter was shown by monosaccharide and methylation analyses, degradation with succinoglycanase and NMR analysis to be a succinoglycan with the structure shown below. (S)-pyruvic acid is found stoichiometrically as 4,6-O-ketal substituent of terminal glucose. Succinic acid is present in 40% of the repeating units and it is attached to O-6 of the 3-linked glucose next to the pyruvate carrying sugar. Some evidence is found that a small amount of succinic acid (ca. 6% of the total) is linked to O-6 of another undetermined glucose.
Carbohydrate Research, 1991
A new oligosaccharide subunit of xyloglucan was isolated from the beta-(1----4)-endoglucanase dig... more A new oligosaccharide subunit of xyloglucan was isolated from the beta-(1----4)-endoglucanase digestion products of the xyloglucan in what is referred to as "sycamore extracellular polysaccharides" and found to be an undecasaccharide having two terminal alpha-L-fucopyranosyl residues. The undecasaccharide was structurally characterized by 1H-n.m.r. spectroscopy, fast-atom bombardment mass spectrometry (f.a.b.-m.s.), and glycosyl-residue and glycosyl-linkage composition analyses. The structure of the undecasaccharide was confirmed by digesting it with a hydrolase that releases alpha-D-Xylp-(1----6)-D-Glc from the non-reducing end of xyloglucan oligosaccharides.
Biomacromolecules, 2007
Copolymers of 3-hydroxybutyrate (3HB) and 3-mercaptopropionate (3MP) or 3-mercaptobutyrate (3MB) ... more Copolymers of 3-hydroxybutyrate (3HB) and 3-mercaptopropionate (3MP) or 3-mercaptobutyrate (3MB) units and minor amounts of 3-hydroxypropionate (3HP), 3-hydroxyvalerate (3HV), or 3-mercaptovalerate (3MV) were investigated regarding their microstructure by NMR, electrospray ionization mass spectrometry, and size exclusion chromatography NMR. These copolymers were produced by Ralstonia eutropha strain H16 when cells were cultivated in a mineral salts medium with gluconate as a carbon source for growth and 3MP or 3MB as precursor substrates for incorporation of 3-mercaptoalkanoates. Mass spectrometry analysis of partially methanolyzed or pyrolyzed samples proved the presence of true copolymers or terpolymers. (13)C NMR spectroscopy of intact polymer samples, with values of average block length and degree of randomness deviating from a random sequence model, suggested microblock structures; however, composition analysis by (1)H NMR of fractions obtained by size exclusion chromatography showed significant variations with molecular weight, revealing the presence of blends of poly(3HB-co-3MP-co-3HP) or poly(3HB-co-3MB) with poly(3HB). The experimental NMR carbonyl dyad signal intensities were satisfactorily matched by a random sequence model when the presence of poly(3HB) was taken into account.
Polymer Degradation and Stability, 1988
... Alberto Ballistreri,a Domenico Garozzo," Mario Giuffrida,b Giuseppe ... more ... Alberto Ballistreri,a Domenico Garozzo," Mario Giuffrida,b Giuseppe Impallomenia Giorgio Montaudoa a Dipartimento di Scienze Chimiche, Universita di Catania, b Istituto per la Chimica e la Tecnologia dei Materiali Polimerici, Consiglio Nazionale delle Ricerche, Viale Andrea ...
Polymer Degradation and Stability, 1989
... Scaiano, J. C.; Tanner, M.; Weir, D. J. Am. ... Domenico Garozzo,t Mario Giuffrida,t and Gior... more ... Scaiano, J. C.; Tanner, M.; Weir, D. J. Am. ... Domenico Garozzo,t Mario Giuffrida,t and Giorgio Montaudo*t Dipartimento di Scienze Chimiche, Uniuersitd di Catania, 95125 Catania, Italy, and Istituto per la Chimica e la Tecnologia dei Materiali Polimerici, Consiglio Nazionale delle ...
European Journal of Pharmaceutical Sciences, 2009
Poly(3-hydroxybutyrate-co-ε-caprolactone) copolymers and poly(3-hydroxybutyrate-co-3hydroxyvalera... more Poly(3-hydroxybutyrate-co-ε-caprolactone) copolymers and poly(3-hydroxybutyrate-co-3hydroxyvalerate-co--caprolactone) terpolymers were used by a solvent deposition technique to prepare either micro-or nanoparticles. In particular, the synthesis and analytical characterization of the terpolymers were described.
Carbohydrate Polymers, 2007
A study of the interaction among sodium alginates of diVerent molecular compositions, water and g... more A study of the interaction among sodium alginates of diVerent molecular compositions, water and glycerol was carried out, in order to weigh up the inXuence of diVerent polymeric microstructures on the chemical-physical properties of Wlms obtained by water soluble blends of sodium alginates and increasing amounts of glycerol. Thermal, mechanical and morphological analyses performed on the Wlms conWrmed the existence of speciWc interactions between sodium alginates and glycerol; it was as well demonstrated that only at speciWc mass ratio between the single polymers and glycerol it is possible to obtain the correct plasticizing eVect induced by glycerol.
Macromolecules, 1990
Two different samples of copolyesters produced by Pseudomonas oleouorans when grown either on non... more Two different samples of copolyesters produced by Pseudomonas oleouorans when grown either on nonanoic acid alone or on an equimolar mixture of nonanoic and octanoic acids were evaluated for sequence distribution by controlled methanolysis to their oligomers, separation of the oligomers by HPLC, and analysis of the fractions so obtained by fast atom bombardment mass spectrometry (FAB-MS). The copolyesters contained primarily 0-hydroxyheptanoate and 0-hydroxynonanoate units, which showed no observable differences in their l H and *3C NMR spectra with changes in composition, so those analyses could not be applied. The observed oligomer composition and that calculated on the basis of Bernoullian statistics for sequence distributions in random copolymers of the compositions studied were in good agreement.
Macromolecules, 1995
Stevioside is a non-cariogenic and low-calorigenic diterpenoid glycoside has slightly bitterness ... more Stevioside is a non-cariogenic and low-calorigenic diterpenoid glycoside has slightly bitterness and bad after taste. Enzymatic modification by alternansucrase from Leuconostoc citreum SK24.002 was utilized in biotransformation of stevioside to remove the bitter taste fully or partially and an aftertaste of the stevioside, using sucrose as donor and stevioside as acceptor. Tri-glucosyl-stevioside produced during alternansucrase acceptor reaction of stevioside were successfully separated using adsorption separation technology of macroporous adsorption resin (AB-8) flowed by semipreparative high performance liquid chromatography. Structure of the product was characterized to be 13-{[α-D-glucopyranosyl-(1→3)-α-D-glucopyranosyl-(1→6)-α-D-glucopyranosyl-(1→3)-β-Dglucopyranosyl-(1→2)-β-D-glucopyranosyl]oxy}kaur-16-en-19-oic acid β-D glucopyranosyl ester on the basis of extensive one dimension and two dimensional NMR and LC-ESI-MS in negative mode data.