A strain of hydrogen producing bacteria was immobilized by polyvinyl alcohol-boric acid method, with the addition of a small amount of calcium alginate. The immobilized cells were insensitive to the presence of traces...A strain of hydrogen producing bacteria was immobilized by polyvinyl alcohol-boric acid method, with the addition of a small amount of calcium alginate. The immobilized cells were insensitive to the presence of traces of O2. Moreover, the immobilized cells increased both the evolution rate and the yield of hydrogen production. Batch experiments with a medium containing 10 g/L glucose demonstrated the yields of hydrogen production by the immobilized and free cells were 2.14 mol/mol glucose and 1.69 mol/mol glucose, respectively. In continuous cultures at medium retention time of 2.0 h, the yield and the evolution rate of hydrogen production by the immobilized cells were 2.31 mol/mol glucose and 1 435.4 ml/（L·h） respectively. However, at medium retention time of 6.0 h, the yield and the evolution rate of hydrogen production by free cells were only 1.75 mol/mol glucose and 362.9 ml/（L·h）, respectively.展开更多
A rod-like NiCo2O4 modified glassy carbon electrode was fabricated and used for non-enzymatic glucose sensing. The NiCo2O4 was prepared by a facile hydrothermal reaction and subsequently treated in a commercial microw...A rod-like NiCo2O4 modified glassy carbon electrode was fabricated and used for non-enzymatic glucose sensing. The NiCo2O4 was prepared by a facile hydrothermal reaction and subsequently treated in a commercial microwave oven to eliminate the residual water introduced during the hydrothermal procedure. Structural analysis showed that there was no significant structural alteration before and after microwave treatment. The elimination of water residuals was confirmed by the stoichiometric ratio change by using element analysis. The microwave treated NiCo2O4 (M-NiCo2O4) showed excellent performance as a glucose sensor (sensitivity 431.29 μA·mmol/L-1·cm-2). The sensing performance decreases dramatically by soaking the M-NiCo2O4 in water. This result indicates that the introduction of residual water during hydrothermal process strongly affects the electrochemical performance and microwave pre-treatment is crucial for better sensory performance.展开更多
The aim of this work is to evaluate the efficiency of ethanol production by fermentation of a hydrolysate obtained by the enzymatic hydrolysis of purple elephant grass （Pennisetum purpureum Schum.） using a blend of ...The aim of this work is to evaluate the efficiency of ethanol production by fermentation of a hydrolysate obtained by the enzymatic hydrolysis of purple elephant grass （Pennisetum purpureum Schum.） using a blend of cellulases. Three hundred grams of 20-mesh granulated purple elephant grass was subjected to hot water pretreatment at 100 ℃ for a period of 25 min in a batch autoclave reactor. The pulp obtained from the pretreatment process was washed with water at 60 ℃ and submitted to enzymatic hydrolysis using a combination of exoglucanases, endoglucanases and beta-glucosidases or β-glucosidases from Novozymes. The pH of the system was kept constant at 4.8 by adjusting the levels of acetic acid or sodium acetate in the buffer solution. Enzymatic hydrolysis occurred at 50 ℃ upon agitation at 200 rpm on a shaker for 72 hours. The hydrolysate obtained after agitation was fermented using dried Saccharomyces cerevisiae yeast （manufactured by Dr. Oetker） at 30 ℃ for 10 hours. The liquids obtained after fermentation were analysed using HPLC to determine the quantity of ethanol produced. After 4 hours of fermentation, the maximum quantity of ethanol was 1.8 g/L. The stoichiometric yield of ethanol was approximately 95%. However, the step ofpretreatment was deemed unsatisfactory due to the loss of glucose during the pretreatment process.展开更多
文摘A strain of hydrogen producing bacteria was immobilized by polyvinyl alcohol-boric acid method, with the addition of a small amount of calcium alginate. The immobilized cells were insensitive to the presence of traces of O2. Moreover, the immobilized cells increased both the evolution rate and the yield of hydrogen production. Batch experiments with a medium containing 10 g/L glucose demonstrated the yields of hydrogen production by the immobilized and free cells were 2.14 mol/mol glucose and 1.69 mol/mol glucose, respectively. In continuous cultures at medium retention time of 2.0 h, the yield and the evolution rate of hydrogen production by the immobilized cells were 2.31 mol/mol glucose and 1 435.4 ml/（L·h） respectively. However, at medium retention time of 6.0 h, the yield and the evolution rate of hydrogen production by free cells were only 1.75 mol/mol glucose and 362.9 ml/（L·h）, respectively.
基金supported by the Shandong Provincial Natural Science Foundation,China(No.ZR2017QB015)the National Natural Science Foundation of China(No.21773309)China University of Petroleum Student’s Platform for Innovation and Entrepreneurship Training Program(No.20161449)
文摘A rod-like NiCo2O4 modified glassy carbon electrode was fabricated and used for non-enzymatic glucose sensing. The NiCo2O4 was prepared by a facile hydrothermal reaction and subsequently treated in a commercial microwave oven to eliminate the residual water introduced during the hydrothermal procedure. Structural analysis showed that there was no significant structural alteration before and after microwave treatment. The elimination of water residuals was confirmed by the stoichiometric ratio change by using element analysis. The microwave treated NiCo2O4 (M-NiCo2O4) showed excellent performance as a glucose sensor (sensitivity 431.29 μA·mmol/L-1·cm-2). The sensing performance decreases dramatically by soaking the M-NiCo2O4 in water. This result indicates that the introduction of residual water during hydrothermal process strongly affects the electrochemical performance and microwave pre-treatment is crucial for better sensory performance.
文摘The aim of this work is to evaluate the efficiency of ethanol production by fermentation of a hydrolysate obtained by the enzymatic hydrolysis of purple elephant grass （Pennisetum purpureum Schum.） using a blend of cellulases. Three hundred grams of 20-mesh granulated purple elephant grass was subjected to hot water pretreatment at 100 ℃ for a period of 25 min in a batch autoclave reactor. The pulp obtained from the pretreatment process was washed with water at 60 ℃ and submitted to enzymatic hydrolysis using a combination of exoglucanases, endoglucanases and beta-glucosidases or β-glucosidases from Novozymes. The pH of the system was kept constant at 4.8 by adjusting the levels of acetic acid or sodium acetate in the buffer solution. Enzymatic hydrolysis occurred at 50 ℃ upon agitation at 200 rpm on a shaker for 72 hours. The hydrolysate obtained after agitation was fermented using dried Saccharomyces cerevisiae yeast （manufactured by Dr. Oetker） at 30 ℃ for 10 hours. The liquids obtained after fermentation were analysed using HPLC to determine the quantity of ethanol produced. After 4 hours of fermentation, the maximum quantity of ethanol was 1.8 g/L. The stoichiometric yield of ethanol was approximately 95%. However, the step ofpretreatment was deemed unsatisfactory due to the loss of glucose during the pretreatment process.
