Biosynthesis and thermal properties of poly（3-hydroxybutyrate-co-3-hydroxyvalerate） （PHBV） with different HV （hydrovalerate） content produced by a Bacillus cereus strain were investigated. A large variety of HV ...Biosynthesis and thermal properties of poly（3-hydroxybutyrate-co-3-hydroxyvalerate） （PHBV） with different HV （hydrovalerate） content produced by a Bacillus cereus strain were investigated. A large variety of HV contents （up to about 90 mol%） of PHBV could be produced by this strain. Combined nitrogen sources containing both yeast extract and ammonium sulphate were better for cell growth and polyhydroxyalkanoates （PHA） production than either yeast extract or ammonium sulphate alone. Propionic acid is more favorable for the production of HV content than that of valeric acid. Finally, thermal properties of PHBV produced by this strain are found close to the results of other groups.展开更多
Poly[R-3-hydroxybutyrate-co-(R-3-hydroxyvalerate)] (PHBVs) copolymers are promising biopolymers, which could substitute petroleum-based plastics for various applications. PHB and PHBV pellets were processed on a custo...Poly[R-3-hydroxybutyrate-co-(R-3-hydroxyvalerate)] (PHBVs) copolymers are promising biopolymers, which could substitute petroleum-based plastics for various applications. PHB and PHBV pellets were processed on a customized 3D printer via Fused Granular Manufacturing (FGM) approach modified with a Mahor screw extruder. To anticipate the behaviour of PHBVs when transformed using conventional thermo-mechanical shaping processes, thermal and mechanical analyses were carried out in order to better understand the effect of annealing temperature on their crystallization behaviour and mechanical properties of PHB polymer and PHBV copolymer. The objectives of the present work were to propose an experimental strategy to study the melting and crystallization events, crystalline structure changes, and mechanical performances of both PHB homopolymer and PHBV copolymer according to identical thermal annealing treatments. A monitoring of 3D printed PHB and PHBV structures was achieved by coupling Differential Scanning Calorimetry (DSC) and tensile tests. .展开更多
Poly (3-hydroxybutyrate-co-3-hydroxyvalerate)/Organophilic montmorillonite (PHBV/OMMT) nanocomposites were prepared and the biodegradability of the PHBV/OMMT nanocomposites was studied by a cultivation degrading metho...Poly (3-hydroxybutyrate-co-3-hydroxyvalerate)/Organophilic montmorillonite (PHBV/OMMT) nanocomposites were prepared and the biodegradability of the PHBV/OMMT nanocomposites was studied by a cultivation degrading method in soil suspension. The relationship between structure and biodegradability of PHBV/OMMT nanocomposites was investigated. The results showed that the biodegradability of PHBV/OMMT nanocomposites decreased with increasing amount of OMMT and it was related to the number of PHBV degrading microorganisms in degradation environment, the anti-microbial property of OMMT and the degree of crystallinity of the nanocomposites.展开更多
The biodegradable polymer demonstrates significant potential for addressing the critical environmental challenges associated with oil spills;however, the cellular film structure and hydrophobic characteristics of the ...The biodegradable polymer demonstrates significant potential for addressing the critical environmental challenges associated with oil spills;however, the cellular film structure and hydrophobic characteristics of the polymer restrict their efficacy. In this study, a biodegradable thin membrane composed of a blend of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(caprolactone) (PCL) was fabricated utilizing the electrospinning technique. The membrane exhibited an adsorption capacity for cooking oil of 10.8 g/g, and Fourier-transform infrared spectroscopy (FTIR) analysis confirmed the anticipated chemical structures, revealing no evidence of chemical interactions between PHBV and PCL. This research presents an environmentally friendly and straightforward approach for fabricating biodegradable membrane structure with exceptional oil-water separation capabilities.展开更多
The feeding method of propionic acid for production ofpoly(3-hydroxybutyrate-co-3-hydro xyvalerate) [P(3HB-co-3HV)] by fed-batch culture of Ralstoniaeutropha was optimized to achieve high cell density and high 3HV yie...The feeding method of propionic acid for production ofpoly(3-hydroxybutyrate-co-3-hydro xyvalerate) [P(3HB-co-3HV)] by fed-batch culture of Ralstoniaeutropha was optimized to achieve high cell density and high 3HV yield. Effects of different feedingstrategies of propionic acid on the production of P(3HB-co-3HV) were investigated. A decline ofspecific synthesis rate of copolymer and the yield of 3HV unit from propionic acid were observed dueto the propionic acid accumulation in culture broth when the feeding solution with highP/G(propionic acid to glucose) ratio was employed. It was further confirmed by controlling propionicacid concentration at a low level in the separate feeding of propionic acid. An optimal feedingstrategy was demonstrated to reduce the propionic acid accumulation. The cell concentration,P(3HB-co-3HV) productivity and 3HV unit fraction reached to 163.9kg·m^(-3), 1.8kg·m^(-3)·h^(-1),and 10.6%(by mass), respectively, resulting in a yield of 0.33g HV per g propionic acid.展开更多
基金This work was financially supported by the Hong Kong Polytechnic University (Grant YD37)the Research Grant Council of the Hong Kong Special Administration Region, China (Nos. Polyu5272/01M, Polyu5257/02M, Polyu5403/03M)
文摘Biosynthesis and thermal properties of poly（3-hydroxybutyrate-co-3-hydroxyvalerate） （PHBV） with different HV （hydrovalerate） content produced by a Bacillus cereus strain were investigated. A large variety of HV contents （up to about 90 mol%） of PHBV could be produced by this strain. Combined nitrogen sources containing both yeast extract and ammonium sulphate were better for cell growth and polyhydroxyalkanoates （PHA） production than either yeast extract or ammonium sulphate alone. Propionic acid is more favorable for the production of HV content than that of valeric acid. Finally, thermal properties of PHBV produced by this strain are found close to the results of other groups.
文摘Poly[R-3-hydroxybutyrate-co-(R-3-hydroxyvalerate)] (PHBVs) copolymers are promising biopolymers, which could substitute petroleum-based plastics for various applications. PHB and PHBV pellets were processed on a customized 3D printer via Fused Granular Manufacturing (FGM) approach modified with a Mahor screw extruder. To anticipate the behaviour of PHBVs when transformed using conventional thermo-mechanical shaping processes, thermal and mechanical analyses were carried out in order to better understand the effect of annealing temperature on their crystallization behaviour and mechanical properties of PHB polymer and PHBV copolymer. The objectives of the present work were to propose an experimental strategy to study the melting and crystallization events, crystalline structure changes, and mechanical performances of both PHB homopolymer and PHBV copolymer according to identical thermal annealing treatments. A monitoring of 3D printed PHB and PHBV structures was achieved by coupling Differential Scanning Calorimetry (DSC) and tensile tests. .
基金The National Natural Science Foundation of China (No. 20374032) Chinese Education Ministry Foundation for N & T Joint Academy
文摘Poly (3-hydroxybutyrate-co-3-hydroxyvalerate)/Organophilic montmorillonite (PHBV/OMMT) nanocomposites were prepared and the biodegradability of the PHBV/OMMT nanocomposites was studied by a cultivation degrading method in soil suspension. The relationship between structure and biodegradability of PHBV/OMMT nanocomposites was investigated. The results showed that the biodegradability of PHBV/OMMT nanocomposites decreased with increasing amount of OMMT and it was related to the number of PHBV degrading microorganisms in degradation environment, the anti-microbial property of OMMT and the degree of crystallinity of the nanocomposites.
文摘The biodegradable polymer demonstrates significant potential for addressing the critical environmental challenges associated with oil spills;however, the cellular film structure and hydrophobic characteristics of the polymer restrict their efficacy. In this study, a biodegradable thin membrane composed of a blend of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(caprolactone) (PCL) was fabricated utilizing the electrospinning technique. The membrane exhibited an adsorption capacity for cooking oil of 10.8 g/g, and Fourier-transform infrared spectroscopy (FTIR) analysis confirmed the anticipated chemical structures, revealing no evidence of chemical interactions between PHBV and PCL. This research presents an environmentally friendly and straightforward approach for fabricating biodegradable membrane structure with exceptional oil-water separation capabilities.
文摘The feeding method of propionic acid for production ofpoly(3-hydroxybutyrate-co-3-hydro xyvalerate) [P(3HB-co-3HV)] by fed-batch culture of Ralstoniaeutropha was optimized to achieve high cell density and high 3HV yield. Effects of different feedingstrategies of propionic acid on the production of P(3HB-co-3HV) were investigated. A decline ofspecific synthesis rate of copolymer and the yield of 3HV unit from propionic acid were observed dueto the propionic acid accumulation in culture broth when the feeding solution with highP/G(propionic acid to glucose) ratio was employed. It was further confirmed by controlling propionicacid concentration at a low level in the separate feeding of propionic acid. An optimal feedingstrategy was demonstrated to reduce the propionic acid accumulation. The cell concentration,P(3HB-co-3HV) productivity and 3HV unit fraction reached to 163.9kg·m^(-3), 1.8kg·m^(-3)·h^(-1),and 10.6%(by mass), respectively, resulting in a yield of 0.33g HV per g propionic acid.
