A new kind of nano-crysta cellulose (NCC) prepared from natural cotton fiber has been obtained by the method ofacid hydrolysis. Compared to most other nanophase materials that derive from inorganic materials, our prod...A new kind of nano-crysta cellulose (NCC) prepared from natural cotton fiber has been obtained by the method ofacid hydrolysis. Compared to most other nanophase materials that derive from inorganic materials, our products are preparedfrom natural cotton fibers. The products are of spherical shape with mixed crystal forms of cellulose I and II. The preparationconditions determine the properties of the products. Prior treatment is a critical procedure. The properties of the products arealso strongly affected by such conditions as the kinds of acids used, the ratio of the acid mixture, the acid concentration, theultrasonic agitation time and hydrolysis temperature. The number average molecular weight of NCC is determined by gelpermeation chromatography (GPC). The particle size and shape were determined by transmission electron microscopy(TEM). X-ray diffraction was used to detect the crystallinity and average crystallite size of the panicle.展开更多
This study aimed to compare the sensitivity of two-phase separation and the filtration method using a mixed cellulose ester(MCE)membrane to detect enteroviruses in sewage samples.From December 2015 to July 2016,four d...This study aimed to compare the sensitivity of two-phase separation and the filtration method using a mixed cellulose ester(MCE)membrane to detect enteroviruses in sewage samples.From December 2015 to July 2016,four domestic sewage samples(1 L/sample)were collected monthly from the Guangzhou Liede Sewage Treatment Plant,and each sewage sample was divided into two aliquots(500 mL).The sewage sample was concentrated using the two-phase separation and the filtration method using an MCE membrane,and the treated solutions were inoculated into cells for enterovirus isolation.Polymerase chain reaction amplification,VP1 sequencing,and enterovirus molecular typing were performed on the positive isolates.The detection rates of poliovirus(PV)and non-polio enterovirus(NPEV)obtained using the filtration method using an MCE membrane were higher than those using the two-phase separation method.McNemar's test showed that the detection rates of PV,NPEV,type 1 Sabin-like(SL1),type 2 Sabin-like(SL2),and type 3 Sabin-like(SL3)strain were not statistically significant(P>0.05).In Guangdong Province,China,the detection rates for PV and NPEV were 53.13%and 62.50%(20/32),respectively.Twenty-seven PVs were isolated,three highly variable strains of the type 1 vaccine,with seven nucleotide substitutions in the VP1 region,compared with the type 1 Sabin strains.Eighty-seven strains of NPEV were isolated and nine serotypes were identified,among which coxsackievirus B3(CVB3),echovirus 6(E6),and echovirus 11(E11)were the dominant strains.The filtration method using an MCE membrane is more sensitive than two-phase separation and can be used as a robust,sensitive,and cost-effective method to isolate enteroviruses from sewage.展开更多
In this paper,a simple and cheap method for producing of amorphous cellulose was studied by treating the initial cellulosic material(MCC and waste paper)with a cold solvent,such as aqueous solution of 7%NaOH/12%Urea,a...In this paper,a simple and cheap method for producing of amorphous cellulose was studied by treating the initial cellulosic material(MCC and waste paper)with a cold solvent,such as aqueous solution of 7%NaOH/12%Urea,at the various ratios of the solvent to cellulose(v/w)(R).If was found that after treatment of cellulose materials with the solvent at R≥5,a completely amorphous cellulose(AC)is formed.Due to high digestibility,the AC with concentration of 50 g/L is converted to glucose almost completely for 48 h under the action of cellulolytic enzyme CTec-3 with a dose of 30 mg/g solid sample.Such sample can be used as an amorphous standard in the study of crystallinity degree and enzymatic hydrolysis of various types of cellulose and lignocellulose.It was found that enzymatic saccharification is most advantageous to carry out at elevated concentrations of AC,150 g/L.Due to high cost of MCC,it is preferable to use a cheap cellulose raw material,such as mixed waste paper(MWP),for the commercial production of AC and glucose.The resulting glucose can find application in biotechnology as a promising nutrient for various microorganisms.展开更多
Cellulose nanocrystal(CNC)with distinctive shape-morphology,enhanced thermal stability and dispersibility is essential for overcoming the challenges in processing polymer/CNC nanocom-posites through melt compounding a...Cellulose nanocrystal(CNC)with distinctive shape-morphology,enhanced thermal stability and dispersibility is essential for overcoming the challenges in processing polymer/CNC nanocom-posites through melt compounding at elevated temperatures.This study shows a mixed acid hy-drolysis method to produce CNC with improved thermal stability and high productivity.The use of phosphoric acid(H_(3)PO_(4)),as a mild acid,in combination with a strong acid either sulphuric acid(H_(2)SO_(4))or hydrochloric acid(HCl)leads to reduced use of strong acids and low impact on our environment.The influences of acid combination and sequence of addition on the production yield were investigated by retaining the proportion of H_(3)PO_(4)to corrosive acid(H_(2)SO_(4)and HCl)4 to 1,and solid to liquid ratio 1꞉75.This methodology has enabled to isolate CNC with higher thermal stability,dispersibility and productivity in terms of amount acid used 1 g of CNC,as compared with single acid hydrolysis.The CNC produced using the combination of H_(3)PO_(4)and HCl exhibits high thermal stability,dispersibility and rod-like shape morphology with length and width of(424±86)and(22±3)nm,respectively.Moreover,this approach has reduced H_(3)PO_(4)consumption by 54%as compared with single acid hydrolysis method for the production of same amount of CNC.展开更多
从某垃圾填埋场的垃圾堆腐物及四川农业大学农场的畜粪和土样中分离到3株降解纤维素能力较高的菌株B1、F1和F2,经初步鉴定,其分别为纤维单孢菌属(Cellu lomonas)、木霉属(Trichoderm a)和青霉属(Pen ic illium)。其中混合菌株B1F1、B1F2...从某垃圾填埋场的垃圾堆腐物及四川农业大学农场的畜粪和土样中分离到3株降解纤维素能力较高的菌株B1、F1和F2,经初步鉴定,其分别为纤维单孢菌属(Cellu lomonas)、木霉属(Trichoderm a)和青霉属(Pen ic illium)。其中混合菌株B1F1、B1F2、F1F2摇床培养8d时滤纸纤维素失重率分别达到49.76%,52.30%,46.02%,均高于单一菌种的滤纸失重率。且CMC酶活也明显提高,比其单一菌株的酶活提高了1.5倍。试验结果表明,由两种不同菌株组成的混合菌分解纤维素能力明显强于其中任何单一菌种,其中两真菌F1F2组合效果最好,且将其制成高纤维素酶活的固体曲,为今后纤维素的固态发酵生产和混合发酵降解纤维素废弃物提供了依据。展开更多
基金This work was supported by the Special Funds for Major State Basic Research Projects (95-12 and G1999064800).
文摘A new kind of nano-crysta cellulose (NCC) prepared from natural cotton fiber has been obtained by the method ofacid hydrolysis. Compared to most other nanophase materials that derive from inorganic materials, our products are preparedfrom natural cotton fibers. The products are of spherical shape with mixed crystal forms of cellulose I and II. The preparationconditions determine the properties of the products. Prior treatment is a critical procedure. The properties of the products arealso strongly affected by such conditions as the kinds of acids used, the ratio of the acid mixture, the acid concentration, theultrasonic agitation time and hydrolysis temperature. The number average molecular weight of NCC is determined by gelpermeation chromatography (GPC). The particle size and shape were determined by transmission electron microscopy(TEM). X-ray diffraction was used to detect the crystallinity and average crystallite size of the panicle.
基金supported by the National Key Research and Development Program of China(Project No.2021YFC2302003)the Natural Science Foundation of Beijing(Project No.L192014).
文摘This study aimed to compare the sensitivity of two-phase separation and the filtration method using a mixed cellulose ester(MCE)membrane to detect enteroviruses in sewage samples.From December 2015 to July 2016,four domestic sewage samples(1 L/sample)were collected monthly from the Guangzhou Liede Sewage Treatment Plant,and each sewage sample was divided into two aliquots(500 mL).The sewage sample was concentrated using the two-phase separation and the filtration method using an MCE membrane,and the treated solutions were inoculated into cells for enterovirus isolation.Polymerase chain reaction amplification,VP1 sequencing,and enterovirus molecular typing were performed on the positive isolates.The detection rates of poliovirus(PV)and non-polio enterovirus(NPEV)obtained using the filtration method using an MCE membrane were higher than those using the two-phase separation method.McNemar's test showed that the detection rates of PV,NPEV,type 1 Sabin-like(SL1),type 2 Sabin-like(SL2),and type 3 Sabin-like(SL3)strain were not statistically significant(P>0.05).In Guangdong Province,China,the detection rates for PV and NPEV were 53.13%and 62.50%(20/32),respectively.Twenty-seven PVs were isolated,three highly variable strains of the type 1 vaccine,with seven nucleotide substitutions in the VP1 region,compared with the type 1 Sabin strains.Eighty-seven strains of NPEV were isolated and nine serotypes were identified,among which coxsackievirus B3(CVB3),echovirus 6(E6),and echovirus 11(E11)were the dominant strains.The filtration method using an MCE membrane is more sensitive than two-phase separation and can be used as a robust,sensitive,and cost-effective method to isolate enteroviruses from sewage.
文摘In this paper,a simple and cheap method for producing of amorphous cellulose was studied by treating the initial cellulosic material(MCC and waste paper)with a cold solvent,such as aqueous solution of 7%NaOH/12%Urea,at the various ratios of the solvent to cellulose(v/w)(R).If was found that after treatment of cellulose materials with the solvent at R≥5,a completely amorphous cellulose(AC)is formed.Due to high digestibility,the AC with concentration of 50 g/L is converted to glucose almost completely for 48 h under the action of cellulolytic enzyme CTec-3 with a dose of 30 mg/g solid sample.Such sample can be used as an amorphous standard in the study of crystallinity degree and enzymatic hydrolysis of various types of cellulose and lignocellulose.It was found that enzymatic saccharification is most advantageous to carry out at elevated concentrations of AC,150 g/L.Due to high cost of MCC,it is preferable to use a cheap cellulose raw material,such as mixed waste paper(MWP),for the commercial production of AC and glucose.The resulting glucose can find application in biotechnology as a promising nutrient for various microorganisms.
文摘Cellulose nanocrystal(CNC)with distinctive shape-morphology,enhanced thermal stability and dispersibility is essential for overcoming the challenges in processing polymer/CNC nanocom-posites through melt compounding at elevated temperatures.This study shows a mixed acid hy-drolysis method to produce CNC with improved thermal stability and high productivity.The use of phosphoric acid(H_(3)PO_(4)),as a mild acid,in combination with a strong acid either sulphuric acid(H_(2)SO_(4))or hydrochloric acid(HCl)leads to reduced use of strong acids and low impact on our environment.The influences of acid combination and sequence of addition on the production yield were investigated by retaining the proportion of H_(3)PO_(4)to corrosive acid(H_(2)SO_(4)and HCl)4 to 1,and solid to liquid ratio 1꞉75.This methodology has enabled to isolate CNC with higher thermal stability,dispersibility and productivity in terms of amount acid used 1 g of CNC,as compared with single acid hydrolysis.The CNC produced using the combination of H_(3)PO_(4)and HCl exhibits high thermal stability,dispersibility and rod-like shape morphology with length and width of(424±86)and(22±3)nm,respectively.Moreover,this approach has reduced H_(3)PO_(4)consumption by 54%as compared with single acid hydrolysis method for the production of same amount of CNC.
文摘从某垃圾填埋场的垃圾堆腐物及四川农业大学农场的畜粪和土样中分离到3株降解纤维素能力较高的菌株B1、F1和F2,经初步鉴定,其分别为纤维单孢菌属(Cellu lomonas)、木霉属(Trichoderm a)和青霉属(Pen ic illium)。其中混合菌株B1F1、B1F2、F1F2摇床培养8d时滤纸纤维素失重率分别达到49.76%,52.30%,46.02%,均高于单一菌种的滤纸失重率。且CMC酶活也明显提高,比其单一菌株的酶活提高了1.5倍。试验结果表明,由两种不同菌株组成的混合菌分解纤维素能力明显强于其中任何单一菌种,其中两真菌F1F2组合效果最好,且将其制成高纤维素酶活的固体曲,为今后纤维素的固态发酵生产和混合发酵降解纤维素废弃物提供了依据。
