Poly(3-hydroxybutyrate) (PHB) is an intracellular carbon and energy storage material accumulated by many kinds of microorganism under unfavorable growth conditions. For the production of PHB, Alcaligenes eutrophus has...Poly(3-hydroxybutyrate) (PHB) is an intracellular carbon and energy storage material accumulated by many kinds of microorganism under unfavorable growth conditions. For the production of PHB, Alcaligenes eutrophus has been widely used because it is easy to grow, and its physiological and biochemical changes during the PHB synthesis is understood in details. A very high concentration and productivity of PHB could be obtained by fed-batch culture of Alcaligenes eutrophus with phosphate limitation in 50 L fermenter.展开更多
Poly-3-hydroxybutyrate （PHB） can be produced by various species of bacteria. Among the possible carbon sources, both methane and methanol could be a suitable substrate for the production of PHB. Methane is cheap and...Poly-3-hydroxybutyrate （PHB） can be produced by various species of bacteria. Among the possible carbon sources, both methane and methanol could be a suitable substrate for the production of PHB. Methane is cheap and plentiful not only as natural gas, but also as biogas. Methanol can also maintain methanotrophic activity in some conditions. The methanotrophic strain Methylosinus trichosporium IMV3011 can accumulate PHB with methane and methanol in a brief nonsterile process. Liquid methanol （0.1%） was added to improve the oxidization of methane. The studies were carried out using shake flasks. Cultivation was performed in two stages： a continuous growth phase and a PHB accumulation phase under the conditions short of essential nutrients （ammonium, nitrate, phosphorus, copper, iron （Ⅲ）, magnesium or ethylenediamine tetraacetate （EDTA）） in batch culture. It was found that the most suitable growth time for the cell is 144 h. Then an optimized culture condition for second stage was determined, in which the PHB concentration could be much increased to 0.6 g/L. In order to increase PHB content, citric acid was added as an inhibitor of tricarboxylic acid cycle （TCA）. It was found that citric acid is favorable for the PHB accumulation, and the PHB yield was increased to 40% （w/w） from the initial yield of 12% （w/w） after nutrient deficiency cultivation. The PHB produced is of very high quality with molecular weight up to 1.5 × 10^6Da.展开更多
The miscibility and crystallization of solution casting biodegradable poly（3-hydroxybuty- rate）/poly（ethylene succinate） （PHB/PES） blends was investigated by differential scanning calorimetry, rheology, and opti...The miscibility and crystallization of solution casting biodegradable poly（3-hydroxybuty- rate）/poly（ethylene succinate） （PHB/PES） blends was investigated by differential scanning calorimetry, rheology, and optical microscopy. The blends showed two glass transition temperatures and a depression of melting temperature of PHB with compositions in phase diagram, which indicated that the blend was partially miscible. The morphology observation supported this result. It was found that the PHB and PES can crystallize simultaneously or upon stepwise depending on the crystallization temperatures and compositions. The spherulite growth rate of PHB increased with increasing of PES content. The influence of compositions on the spherulitic growth rate for the partially miscible polymer blends was discussed.展开更多
Microglial activation plays an important role in a panel of neurological disorders such as multiple sclerosis(MS) and Parkinson's disease(PD),and is a key target for developing therapeutic strategies for these dis...Microglial activation plays an important role in a panel of neurological disorders such as multiple sclerosis(MS) and Parkinson's disease(PD),and is a key target for developing therapeutic strategies for these diseases.Ketogenic diet (KD),which is able to inhibit microglial activation in substantia nigra pars compacta of mice,has been shown effective in a mouse model of PD,possibly through increasing D-β-hydroxybutyrate(D-β-HB),a major component of ketone bodies.To verify this,we developed an in vitro model of microglia activation with a microglia line,BV-2,and investigated how D-β-HB have an effect on the LPS-stimulated BV-2 cells.We found D-β-HB is able to recover the cell viability,and inhibit the production of inflammatory mediators and cytokines such as ROS,nitrite,IL-1β,TNF-α,and IL-6,which otherwise were increased in LPS-stimulated BV-2 cells.We conclude that the LPS induced BV-2 cells activation is a valid in vitro model of microglia activation.D-β-HB is able to suppress the activation of BV-2 cells, which might account for one of the possible reasons of KD therapy on the PD model.展开更多
An economical and environmental sustainability of bioplastic production is dependent on the use of low cost and waste C-sources as raw materials. OMW （Olive Mill Wastewater） with its high organic load represents a d...An economical and environmental sustainability of bioplastic production is dependent on the use of low cost and waste C-sources as raw materials. OMW （Olive Mill Wastewater） with its high organic load represents a dangerous polluting waste. Herein the authors present an integrated process for the simultaneous recovery of polyphenols, high value natural antioxidants, production of PHAs （polyhydroxyalkanotes）, thermoplastic bio-polymers, in particular of PHB （poly-3-hydroxybutyrate） starting from OMW. The combination of membrane filtration and bacterial digestion of OMW resulted in very high yields of polyphenols （3 2.5 g/L） and PHB （31.4 mg/L.h） if compared with the state of the art. These results make the technical approach described here effective for reducing the polluting effect of OMW and maximizing the valuable product yield. Moreover the process is readily suitable for an industrial scale PHB production from OMW.展开更多
This study was aimed to construct a biodegradable but reliable 3-β-hydroxybutymte biosensor. In this context a versatile paper based biosensor, quickly, easily and cheaply fabricated is reported. The procedure of fab...This study was aimed to construct a biodegradable but reliable 3-β-hydroxybutymte biosensor. In this context a versatile paper based biosensor, quickly, easily and cheaply fabricated is reported. The procedure of fabrication is based on the assumption that the introduction of the enzyme in the carbon ink will allow enzyme stabilization and facilitate the study of the catalysis of enzymes and the detection of substrates. To prove this concept we use the enzyme 3-hydroxybutyrate dehydrogenase, in aqueous solution. This enzyme was chosen because it catalyzes the 3-β-hydroxybutyrate, which results from ketoacidosis. The quantification this substance in the diabetics＇ blood is very important as it can increase the reliability of the diagnosis of glycaemia. To prove the multi-use of this biosensor we not only study the redox process in steady state and during the catalytic process, but also detected and quantify the 3-β-hydroxybutyrate. Our results showed that it was possible to study the redox process that occurred during the catalysis and to confirm the amino acid residues that participate in it. It was also observed that glucose and ascorbic acid can interfere in the detection and quantification of the 3-β-hydroxybutyrate, what should be in mind when the quantification of the 3-β-hydroxybutyrate is made in blood samples.展开更多
文摘Poly(3-hydroxybutyrate) (PHB) is an intracellular carbon and energy storage material accumulated by many kinds of microorganism under unfavorable growth conditions. For the production of PHB, Alcaligenes eutrophus has been widely used because it is easy to grow, and its physiological and biochemical changes during the PHB synthesis is understood in details. A very high concentration and productivity of PHB could be obtained by fed-batch culture of Alcaligenes eutrophus with phosphate limitation in 50 L fermenter.
基金New Century Excellent Talents in University of China(NCET-05-0358)the National Natural Science Foundation of China(20625308)
文摘Poly-3-hydroxybutyrate （PHB） can be produced by various species of bacteria. Among the possible carbon sources, both methane and methanol could be a suitable substrate for the production of PHB. Methane is cheap and plentiful not only as natural gas, but also as biogas. Methanol can also maintain methanotrophic activity in some conditions. The methanotrophic strain Methylosinus trichosporium IMV3011 can accumulate PHB with methane and methanol in a brief nonsterile process. Liquid methanol （0.1%） was added to improve the oxidization of methane. The studies were carried out using shake flasks. Cultivation was performed in two stages： a continuous growth phase and a PHB accumulation phase under the conditions short of essential nutrients （ammonium, nitrate, phosphorus, copper, iron （Ⅲ）, magnesium or ethylenediamine tetraacetate （EDTA）） in batch culture. It was found that the most suitable growth time for the cell is 144 h. Then an optimized culture condition for second stage was determined, in which the PHB concentration could be much increased to 0.6 g/L. In order to increase PHB content, citric acid was added as an inhibitor of tricarboxylic acid cycle （TCA）. It was found that citric acid is favorable for the PHB accumulation, and the PHB yield was increased to 40% （w/w） from the initial yield of 12% （w/w） after nutrient deficiency cultivation. The PHB produced is of very high quality with molecular weight up to 1.5 × 10^6Da.
基金ACKNOWLEDGMENT This work was supported by the Key Science Foundation of Education Ministry of China and the Anhui Science Foundation.
文摘The miscibility and crystallization of solution casting biodegradable poly（3-hydroxybuty- rate）/poly（ethylene succinate） （PHB/PES） blends was investigated by differential scanning calorimetry, rheology, and optical microscopy. The blends showed two glass transition temperatures and a depression of melting temperature of PHB with compositions in phase diagram, which indicated that the blend was partially miscible. The morphology observation supported this result. It was found that the PHB and PES can crystallize simultaneously or upon stepwise depending on the crystallization temperatures and compositions. The spherulite growth rate of PHB increased with increasing of PES content. The influence of compositions on the spherulitic growth rate for the partially miscible polymer blends was discussed.
文摘Microglial activation plays an important role in a panel of neurological disorders such as multiple sclerosis(MS) and Parkinson's disease(PD),and is a key target for developing therapeutic strategies for these diseases.Ketogenic diet (KD),which is able to inhibit microglial activation in substantia nigra pars compacta of mice,has been shown effective in a mouse model of PD,possibly through increasing D-β-hydroxybutyrate(D-β-HB),a major component of ketone bodies.To verify this,we developed an in vitro model of microglia activation with a microglia line,BV-2,and investigated how D-β-HB have an effect on the LPS-stimulated BV-2 cells.We found D-β-HB is able to recover the cell viability,and inhibit the production of inflammatory mediators and cytokines such as ROS,nitrite,IL-1β,TNF-α,and IL-6,which otherwise were increased in LPS-stimulated BV-2 cells.We conclude that the LPS induced BV-2 cells activation is a valid in vitro model of microglia activation.D-β-HB is able to suppress the activation of BV-2 cells, which might account for one of the possible reasons of KD therapy on the PD model.
文摘An economical and environmental sustainability of bioplastic production is dependent on the use of low cost and waste C-sources as raw materials. OMW （Olive Mill Wastewater） with its high organic load represents a dangerous polluting waste. Herein the authors present an integrated process for the simultaneous recovery of polyphenols, high value natural antioxidants, production of PHAs （polyhydroxyalkanotes）, thermoplastic bio-polymers, in particular of PHB （poly-3-hydroxybutyrate） starting from OMW. The combination of membrane filtration and bacterial digestion of OMW resulted in very high yields of polyphenols （3 2.5 g/L） and PHB （31.4 mg/L.h） if compared with the state of the art. These results make the technical approach described here effective for reducing the polluting effect of OMW and maximizing the valuable product yield. Moreover the process is readily suitable for an industrial scale PHB production from OMW.
文摘This study was aimed to construct a biodegradable but reliable 3-β-hydroxybutymte biosensor. In this context a versatile paper based biosensor, quickly, easily and cheaply fabricated is reported. The procedure of fabrication is based on the assumption that the introduction of the enzyme in the carbon ink will allow enzyme stabilization and facilitate the study of the catalysis of enzymes and the detection of substrates. To prove this concept we use the enzyme 3-hydroxybutyrate dehydrogenase, in aqueous solution. This enzyme was chosen because it catalyzes the 3-β-hydroxybutyrate, which results from ketoacidosis. The quantification this substance in the diabetics＇ blood is very important as it can increase the reliability of the diagnosis of glycaemia. To prove the multi-use of this biosensor we not only study the redox process in steady state and during the catalytic process, but also detected and quantify the 3-β-hydroxybutyrate. Our results showed that it was possible to study the redox process that occurred during the catalysis and to confirm the amino acid residues that participate in it. It was also observed that glucose and ascorbic acid can interfere in the detection and quantification of the 3-β-hydroxybutyrate, what should be in mind when the quantification of the 3-β-hydroxybutyrate is made in blood samples.
