The ability of catalyzing indole into indigo of gene engineering strain expressing P450 BM3 immobi- lized by entrapment in calcium-alginate gel capsules was examined,and various characteristics of immobilized cells we...The ability of catalyzing indole into indigo of gene engineering strain expressing P450 BM3 immobi- lized by entrapment in calcium-alginate gel capsules was examined,and various characteristics of immobilized cells were assessed.Optimum conditions for cells activity were not affected after immobilization,and pH and tempera- ture for both free and immobilized cells were found to be pH 7.5 and 35℃,respectively.The immobilized cells ex- hibited a markedly improved thermal stability than free cells.After five repeated experiments,the yield of indigo with the immobilized cells retained over 94%of their original activity,which indicated that the operational stability for recycling in batch processes was improved.展开更多
针对海藻酸钙水凝胶空心纤维拉伸性能较差、应用受到限制的缺点,通过添加二氧化硅形成纳米复合水凝胶来提高其拉伸性能。研究发现,随着添加二氧化硅浓度的增加,水凝胶的拉伸性能呈现先增加再降低的趋势,其饱和浓度为3%。此时,凝胶的拉...针对海藻酸钙水凝胶空心纤维拉伸性能较差、应用受到限制的缺点,通过添加二氧化硅形成纳米复合水凝胶来提高其拉伸性能。研究发现,随着添加二氧化硅浓度的增加,水凝胶的拉伸性能呈现先增加再降低的趋势,其饱和浓度为3%。此时,凝胶的拉伸强度达到最大值,为444 k Pa。与未添加二氧化硅的凝胶相比,拉伸强度和断裂伸长率分别提高了600%和23%。采用该条件通过微流控方法一步制备了二氧化硅纳米复合水凝胶的中空微纤维,应用光学显微镜和扫描电子显微镜对其空心结构进行了表征。同时应用傅立叶变换红外光谱对其分子结构进行了分析。最后,考察了编织方法对凝胶纤维拉伸性能改善的效果。展开更多
The ability of Yarrowia lipolytica W29 immobilized by calcium alginate to degrade oil and chemical oxygen demand （COD） was examined. The degradation rules of oil and COD by immobilized cells with the cell density of...The ability of Yarrowia lipolytica W29 immobilized by calcium alginate to degrade oil and chemical oxygen demand （COD） was examined. The degradation rules of oil and COD by immobilized cells with the cell density of 6.65 × 10^6 CFU/mL degraded 2000 mg/L oil and 2000 mg/L COD within 50 h at 30℃ （pH 7.0, 150 r/min）, similarly to those of free cells, and the degradation efficiencies of oil and COD by immobilized cells were above 80%, respectively. The factors affecting oil and COD degradation by immobilized cells were investigated, the results showed that immobilized cells had high thermostability compared to that of free cells, and substrate concentration significantly affected degrading ability of immobilized cells. Storage stability and reusability tests revealed that the oil degradation ability of immobilized cells was stable after storing at 4~C for 30 d and reuse for 12 times, respectively, the COD degradation rate of immobilized cells was also maintained 82% at the sixth cycle. These results suggested that immobilized Y lipolytica might be applicable to a wastewater treatment system for the removal of oil and COD.展开更多
Kaolin has been widely used as an adsorbent to remove heavy metal ions from aqueous solutions. However, the lower heavy metal adsorption capacity of kaolin limits its practical application. A novel environmental frien...Kaolin has been widely used as an adsorbent to remove heavy metal ions from aqueous solutions. However, the lower heavy metal adsorption capacity of kaolin limits its practical application. A novel environmental friendly material, calcium alginate immobilized kaolin （kaolin/CA）, was prepared using a sol-gel method. The effects of contact time, pH, adsorbent dose, and temperature on Cu2＋ adsorption by kaolin/CA were investigated. The Langmuir isotherm was used to describe the experimental adsorption, the maximum Cu2＋ adsorption capacity of the kaolin/CA reached up to 53.63 mg/g. The thermodynamic studies showed that the adsorption reaction was a spontaneous and endothermic process.展开更多
基金Supported by the National Natural Science Foundation of China （No.30570411）. The authors wish to thank Prof R. D. Schmid （Institute of Technical Biochemistry, University of Stuttgart, Germany）, as he gave us some materials and much help.
文摘The ability of catalyzing indole into indigo of gene engineering strain expressing P450 BM3 immobi- lized by entrapment in calcium-alginate gel capsules was examined,and various characteristics of immobilized cells were assessed.Optimum conditions for cells activity were not affected after immobilization,and pH and tempera- ture for both free and immobilized cells were found to be pH 7.5 and 35℃,respectively.The immobilized cells ex- hibited a markedly improved thermal stability than free cells.After five repeated experiments,the yield of indigo with the immobilized cells retained over 94%of their original activity,which indicated that the operational stability for recycling in batch processes was improved.
文摘针对海藻酸钙水凝胶空心纤维拉伸性能较差、应用受到限制的缺点,通过添加二氧化硅形成纳米复合水凝胶来提高其拉伸性能。研究发现,随着添加二氧化硅浓度的增加,水凝胶的拉伸性能呈现先增加再降低的趋势,其饱和浓度为3%。此时,凝胶的拉伸强度达到最大值,为444 k Pa。与未添加二氧化硅的凝胶相比,拉伸强度和断裂伸长率分别提高了600%和23%。采用该条件通过微流控方法一步制备了二氧化硅纳米复合水凝胶的中空微纤维,应用光学显微镜和扫描电子显微镜对其空心结构进行了表征。同时应用傅立叶变换红外光谱对其分子结构进行了分析。最后,考察了编织方法对凝胶纤维拉伸性能改善的效果。
基金supported by the National Key Technologies R & D Program of China (No. 2007BAC23B01)the Program of Department of Education, Jiangxi Province, China (No. 2007-41).
文摘The ability of Yarrowia lipolytica W29 immobilized by calcium alginate to degrade oil and chemical oxygen demand （COD） was examined. The degradation rules of oil and COD by immobilized cells with the cell density of 6.65 × 10^6 CFU/mL degraded 2000 mg/L oil and 2000 mg/L COD within 50 h at 30℃ （pH 7.0, 150 r/min）, similarly to those of free cells, and the degradation efficiencies of oil and COD by immobilized cells were above 80%, respectively. The factors affecting oil and COD degradation by immobilized cells were investigated, the results showed that immobilized cells had high thermostability compared to that of free cells, and substrate concentration significantly affected degrading ability of immobilized cells. Storage stability and reusability tests revealed that the oil degradation ability of immobilized cells was stable after storing at 4~C for 30 d and reuse for 12 times, respectively, the COD degradation rate of immobilized cells was also maintained 82% at the sixth cycle. These results suggested that immobilized Y lipolytica might be applicable to a wastewater treatment system for the removal of oil and COD.
基金supported by the National Natural Science Foundation of China (No. 50802045,20975056/B050902)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry,and the Middleaged and Youth Scientist Incentive Foundation of Shandong Province (No.BS09018)
文摘Kaolin has been widely used as an adsorbent to remove heavy metal ions from aqueous solutions. However, the lower heavy metal adsorption capacity of kaolin limits its practical application. A novel environmental friendly material, calcium alginate immobilized kaolin （kaolin/CA）, was prepared using a sol-gel method. The effects of contact time, pH, adsorbent dose, and temperature on Cu2＋ adsorption by kaolin/CA were investigated. The Langmuir isotherm was used to describe the experimental adsorption, the maximum Cu2＋ adsorption capacity of the kaolin/CA reached up to 53.63 mg/g. The thermodynamic studies showed that the adsorption reaction was a spontaneous and endothermic process.
