According to the sequence of the bile salt hydrolase （BSH） gene of Bifidobacterium and the restriction enzyme cutting sites of expression vector pNZ8148, primers were designed and the bile salt hydrolase （BSH） gen...According to the sequence of the bile salt hydrolase （BSH） gene of Bifidobacterium and the restriction enzyme cutting sites of expression vector pNZ8148, primers were designed and the bile salt hydrolase （BSH） gene was gotten from Bacillus bifidus ATCC 29521 by PCR. BSH gene was inserted into lactic acid bacteria expression vector pNZ8148 to construct the recombinant pNZ8148-BSH. The recombinant pNZ8148-BSH was transferred into lactic acid bacteria NZ9000 with electrotransformation method. And the recombinant which could express BSH protein was obtained. It was identified by SDS-PAGE electrophoresis and activity verification. The result could provide a rationale reference for expressing BSH in lactic acid bacteria.展开更多
The pretreatment for the removal of small molecules from poly(acrylic acid) sodium (PAAS) solution by continuous diafiltration was investigated using ultrafiltration membrane. The effects of PAAS concentration, pH, tr...The pretreatment for the removal of small molecules from poly(acrylic acid) sodium (PAAS) solution by continuous diafiltration was investigated using ultrafiltration membrane. The effects of PAAS concentration, pH, trans-membrane pressure and pretreatment time on the permeate concentration and permeate flux were studied. The results show that the necessary pretreatment time (NPT) increases with PAAS concentration, decreases with TMP. The change trend of permeate flux with time is affected by pH. The permeate fluxes rapidly decrease from the start, and then increase gradually to stable values at pH 5.0, pH 7.0 and pH 9.3. However, it decreases gradually with time till a state value at pH 3.0 (iso-electric point, IEP). The removal of small molecules is easy at pH greater than iso-electric point (IEP). The change of filtration potential with time indicates the similar trend to that of permeation concentration, but the former is more convenient for indication of NPT.展开更多
Eight cholesterol-lowering lactic acid bacteria(LAB 1 through 8)isolated from pickles and yogurt were evaluated for probiotic potential based on their tolerance to low pH and bile salt and antagonistic activity agains...Eight cholesterol-lowering lactic acid bacteria(LAB 1 through 8)isolated from pickles and yogurt were evaluated for probiotic potential based on their tolerance to low pH and bile salt and antagonistic activity against Staphylococcus aureusand Escherichia coli.Strain LAB 4 had excellent tolerance to low pH and bile salt and all 8 LAB strains had antagonisticactivity against Staphylococcus aureus and Escherichia coli.Moreover,strain LAB4 had synergic cholesterol-lowering effect with 0.0125%licorice root extract,0.025%Chinese wolfberry extract or 0.025%milkvetch root extract.展开更多
The trail was designed to study on technique aspects of ensiling rice straw （RS） appended amounts of lactobacillus. There were two groups according to silage ways, baled silage （BS） and chopped silage （CS）, in w...The trail was designed to study on technique aspects of ensiling rice straw （RS） appended amounts of lactobacillus. There were two groups according to silage ways, baled silage （BS） and chopped silage （CS）, in which lactobacillus was added at levels of 10, 15 and 20 mg·kg^-1, respectively and the mixtures were placed into a packed polyethylene bags and stored at room temperature for 45 days. The results showed that lactobacillus had remarkable effect on fermentation characteristics of RS. The quality of the silage was improved with the lactobacillus addition. In the experiment the optimal quality of rice straw silage （RSS） can be obtained when lactobacillus was added with 15 or 20 mg·kg^-1 level. The effect of different silage methods was very remarkable to the silage quality of same material. The quality of CS was better than that of long silage, at the same time, BS was feasible on condition of eligible level of lactic acid bacteria.展开更多
Stable and monodispersed silver nanoparticles were produced through a mild,convenient,one-pot method based on the reduction of silver nitrate in the presence of poly(amic acid) (PAA) as a stabilizer.The surface plasma...Stable and monodispersed silver nanoparticles were produced through a mild,convenient,one-pot method based on the reduction of silver nitrate in the presence of poly(amic acid) (PAA) as a stabilizer.The surface plasma band transition was monitored along with time in the reaction mixture for three sets of experiments by ultraviolet-visible spectroscopy.Analysis of the data with the Avrami equation yielded n exponent with values between 0.5 and 1.5,demonstrating three-dimensional heterogeneous nucleation and diffusion-controlled growth,accompanied by soft impingement effect.XRD and TEM analyses show a softly agglomerated polycrystalline state and a nearly spherical morphology (<50 nm) of nanoparticles.The FT-IR result indicates that the PAA molecular structure could be hardly influenced by the formation of nanoparticles.展开更多
A new reaction system was designed to economically convert glucose to lactic acid environment-friendly. Hydrophobic ionic liquids were chosen as solvent that can promote the decomposition reaction of glucose, and the ...A new reaction system was designed to economically convert glucose to lactic acid environment-friendly. Hydrophobic ionic liquids were chosen as solvent that can promote the decomposition reaction of glucose, and the catalytic performance of the solid bases was evaluated. Both the reaction temperature and time can affect the yield of lactic acid. A high yield （97%） of lactic acid was achieved under the optimal reaction condition. The IH NMR spectra and HPLC-MS were used to identify the formation of the lactic acid and variations of ionic liquid. It is found that ionic-liquids have a unique solvent effect for glucose and bases. Water can be used as solvent to extract calcium lactate. This shows a great potential of hydrophobic ionic liquids in the solid bases catalyzed reaction that is limited by the weak solubility of solid bases in organic and water solution.展开更多
基金Supported by 863 Projects (2008AA10Z311)National Science and Technology Support Projects (2009BADB9B06)+1 种基金Started Post-doctoral Research Grant of Heilongjiang Province (LBH-Q07023)Harbin Technological Innovation of Special Funds (2007RFQXN020)
文摘According to the sequence of the bile salt hydrolase （BSH） gene of Bifidobacterium and the restriction enzyme cutting sites of expression vector pNZ8148, primers were designed and the bile salt hydrolase （BSH） gene was gotten from Bacillus bifidus ATCC 29521 by PCR. BSH gene was inserted into lactic acid bacteria expression vector pNZ8148 to construct the recombinant pNZ8148-BSH. The recombinant pNZ8148-BSH was transferred into lactic acid bacteria NZ9000 with electrotransformation method. And the recombinant which could express BSH protein was obtained. It was identified by SDS-PAGE electrophoresis and activity verification. The result could provide a rationale reference for expressing BSH in lactic acid bacteria.
基金Projects(21176264,21476265)supported by the National Natural Science Foundation of China
文摘The pretreatment for the removal of small molecules from poly(acrylic acid) sodium (PAAS) solution by continuous diafiltration was investigated using ultrafiltration membrane. The effects of PAAS concentration, pH, trans-membrane pressure and pretreatment time on the permeate concentration and permeate flux were studied. The results show that the necessary pretreatment time (NPT) increases with PAAS concentration, decreases with TMP. The change trend of permeate flux with time is affected by pH. The permeate fluxes rapidly decrease from the start, and then increase gradually to stable values at pH 5.0, pH 7.0 and pH 9.3. However, it decreases gradually with time till a state value at pH 3.0 (iso-electric point, IEP). The removal of small molecules is easy at pH greater than iso-electric point (IEP). The change of filtration potential with time indicates the similar trend to that of permeation concentration, but the former is more convenient for indication of NPT.
文摘Eight cholesterol-lowering lactic acid bacteria(LAB 1 through 8)isolated from pickles and yogurt were evaluated for probiotic potential based on their tolerance to low pH and bile salt and antagonistic activity against Staphylococcus aureusand Escherichia coli.Strain LAB 4 had excellent tolerance to low pH and bile salt and all 8 LAB strains had antagonisticactivity against Staphylococcus aureus and Escherichia coli.Moreover,strain LAB4 had synergic cholesterol-lowering effect with 0.0125%licorice root extract,0.025%Chinese wolfberry extract or 0.025%milkvetch root extract.
基金Heilongjiang Dairy Project Italian Grant Project
文摘The trail was designed to study on technique aspects of ensiling rice straw （RS） appended amounts of lactobacillus. There were two groups according to silage ways, baled silage （BS） and chopped silage （CS）, in which lactobacillus was added at levels of 10, 15 and 20 mg·kg^-1, respectively and the mixtures were placed into a packed polyethylene bags and stored at room temperature for 45 days. The results showed that lactobacillus had remarkable effect on fermentation characteristics of RS. The quality of the silage was improved with the lactobacillus addition. In the experiment the optimal quality of rice straw silage （RSS） can be obtained when lactobacillus was added with 15 or 20 mg·kg^-1 level. The effect of different silage methods was very remarkable to the silage quality of same material. The quality of CS was better than that of long silage, at the same time, BS was feasible on condition of eligible level of lactic acid bacteria.
基金Project(10JJ5057)supported by the Hunan Provincial Natural Science Foundation of China
文摘Stable and monodispersed silver nanoparticles were produced through a mild,convenient,one-pot method based on the reduction of silver nitrate in the presence of poly(amic acid) (PAA) as a stabilizer.The surface plasma band transition was monitored along with time in the reaction mixture for three sets of experiments by ultraviolet-visible spectroscopy.Analysis of the data with the Avrami equation yielded n exponent with values between 0.5 and 1.5,demonstrating three-dimensional heterogeneous nucleation and diffusion-controlled growth,accompanied by soft impingement effect.XRD and TEM analyses show a softly agglomerated polycrystalline state and a nearly spherical morphology (<50 nm) of nanoparticles.The FT-IR result indicates that the PAA molecular structure could be hardly influenced by the formation of nanoparticles.
基金Project(2006BAE02B05) supported by the Key Projects in the National Science and Technology Pillar Program During the 11th Five-year Plan PeriodProject(2005CB221406) supported by the National Basic Research Program of China
文摘A new reaction system was designed to economically convert glucose to lactic acid environment-friendly. Hydrophobic ionic liquids were chosen as solvent that can promote the decomposition reaction of glucose, and the catalytic performance of the solid bases was evaluated. Both the reaction temperature and time can affect the yield of lactic acid. A high yield （97%） of lactic acid was achieved under the optimal reaction condition. The IH NMR spectra and HPLC-MS were used to identify the formation of the lactic acid and variations of ionic liquid. It is found that ionic-liquids have a unique solvent effect for glucose and bases. Water can be used as solvent to extract calcium lactate. This shows a great potential of hydrophobic ionic liquids in the solid bases catalyzed reaction that is limited by the weak solubility of solid bases in organic and water solution.
