Cadaverine. a natural polyamine with multiple bioactivities that is widely distributed in prokaryotes and eukaryotes, is becoming an important industrial chemical. Cadaverine exhibits broad prospects for various appli...Cadaverine. a natural polyamine with multiple bioactivities that is widely distributed in prokaryotes and eukaryotes, is becoming an important industrial chemical. Cadaverine exhibits broad prospects for various applications, especially as an important monomer for bio-based polyamides. Cadaverine-based polyamide PA 5X has broad application prospects owing to its environmentally friendly characteristics and exceptional performance in water absorption and dimensional stability. In this review, we summarize recent findings on the biosynthesis, metabolism, and physiological function of cadaverine in bacteria, with a focus on the regu- latory mechanism of cadaverine synthesis in Escherichia coil （E. coli）. We also describe recent developments in bacterial production of cadaverine by direct fermentation and whole-cell bioconversion, and recent approaches for the separation and purification of cadaverine. In addition, we present an overview of the ap- plication of cadaverine in the synthesis of completely bio-based polyamides. Finally. we provide an outlook and suggest future developments to advance the production of cadaverine from renewable resources.展开更多
Preliminary study on concentration and separation of tin(Sn) from copper alloy dross by selective dissolution method was conducted. The tin in the copper alloy dross did not dissolve in an aqueous nitric acid solution...Preliminary study on concentration and separation of tin(Sn) from copper alloy dross by selective dissolution method was conducted. The tin in the copper alloy dross did not dissolve in an aqueous nitric acid solution which could allow separation of tin from the copper alloy dross. The tin as H2SnO3(metastannic acid) phase was precipitated in the solution with centrifuging process and transformed to tin dioxide(SnO2) after drying process. The dried sample was heat-treated at low temperature and its phase characteristics, surface morphology and chemical composition were investigated.展开更多
The rapid increase in population in Thika has led to increase in municipal solid waste generation, which has posed challenges in the waste disposal and management. This study was carried out to quantify and characteri...The rapid increase in population in Thika has led to increase in municipal solid waste generation, which has posed challenges in the waste disposal and management. This study was carried out to quantify and characterize the waste generated within Thika municipality. Six months data （between March 2014 and August 2014） of waste stream at the dumpsite was reviewed and analyzed. The survey indicated that 66.95% ± 0.34% of the total waste dumped originated from the municipal council ofThika （MCT）. It constitutes of domestic, commercial and institutional waste. 33.05% is industrial waste. Sixty eight percent （68%） of the waste consisted primarily of four components： paper, plastic, organics and food. Food accounted for 15.51% ± 0.95%, paper 18.31% ± 1.7%, plastics 17.89% ± 0.81% and organics other than food 16.51% ±1.01%, respectively obtained at 95% confidence level. Each of the components has some level of recovery. Some of the reusable and recyclable materials were being recovered, food waste had the highest recovery rate of 23% ± 1.7% and was used as animal feed, while plastic （soft plastic） 17% ± 0.93% was sold to recyclers. Recovery of materials for recycling and composting was estimated at 10.21 tonnes or 11.35% of daily generation, leaving 76.44 tonnes per day that can be converted into useful energy. The study shows waste in this dumpsite can be exploited to by converting it to energy thus a good solution for waste management.展开更多
基金This work was supported by the National Key Research and Development Program （2016YFA0204300） the National Natural Science Foundation of China （21390200, 31440024） and the Tech- nology Support Program of Gansu Provincial S＆T Department, China （1304FKCE106）.
文摘Cadaverine. a natural polyamine with multiple bioactivities that is widely distributed in prokaryotes and eukaryotes, is becoming an important industrial chemical. Cadaverine exhibits broad prospects for various applications, especially as an important monomer for bio-based polyamides. Cadaverine-based polyamide PA 5X has broad application prospects owing to its environmentally friendly characteristics and exceptional performance in water absorption and dimensional stability. In this review, we summarize recent findings on the biosynthesis, metabolism, and physiological function of cadaverine in bacteria, with a focus on the regu- latory mechanism of cadaverine synthesis in Escherichia coil （E. coli）. We also describe recent developments in bacterial production of cadaverine by direct fermentation and whole-cell bioconversion, and recent approaches for the separation and purification of cadaverine. In addition, we present an overview of the ap- plication of cadaverine in the synthesis of completely bio-based polyamides. Finally. we provide an outlook and suggest future developments to advance the production of cadaverine from renewable resources.
基金supported by the "Energy Efficiency & Resources" of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (No. 20125010100030-11-2-400)
文摘Preliminary study on concentration and separation of tin(Sn) from copper alloy dross by selective dissolution method was conducted. The tin in the copper alloy dross did not dissolve in an aqueous nitric acid solution which could allow separation of tin from the copper alloy dross. The tin as H2SnO3(metastannic acid) phase was precipitated in the solution with centrifuging process and transformed to tin dioxide(SnO2) after drying process. The dried sample was heat-treated at low temperature and its phase characteristics, surface morphology and chemical composition were investigated.
文摘The rapid increase in population in Thika has led to increase in municipal solid waste generation, which has posed challenges in the waste disposal and management. This study was carried out to quantify and characterize the waste generated within Thika municipality. Six months data （between March 2014 and August 2014） of waste stream at the dumpsite was reviewed and analyzed. The survey indicated that 66.95% ± 0.34% of the total waste dumped originated from the municipal council ofThika （MCT）. It constitutes of domestic, commercial and institutional waste. 33.05% is industrial waste. Sixty eight percent （68%） of the waste consisted primarily of four components： paper, plastic, organics and food. Food accounted for 15.51% ± 0.95%, paper 18.31% ± 1.7%, plastics 17.89% ± 0.81% and organics other than food 16.51% ±1.01%, respectively obtained at 95% confidence level. Each of the components has some level of recovery. Some of the reusable and recyclable materials were being recovered, food waste had the highest recovery rate of 23% ± 1.7% and was used as animal feed, while plastic （soft plastic） 17% ± 0.93% was sold to recyclers. Recovery of materials for recycling and composting was estimated at 10.21 tonnes or 11.35% of daily generation, leaving 76.44 tonnes per day that can be converted into useful energy. The study shows waste in this dumpsite can be exploited to by converting it to energy thus a good solution for waste management.
