To assess the aquatic ecosystem safety for silica （SiO2） nanoparticles （NPs）, the growth inhibition and photosynthetic pigment contents of Scenedesmus obliquus in logarithm growth phase exposed to SiO2 NPs and SiO...To assess the aquatic ecosystem safety for silica （SiO2） nanoparticles （NPs）, the growth inhibition and photosynthetic pigment contents of Scenedesmus obliquus in logarithm growth phase exposed to SiO2 NPs and SiO2 bulk particles （BPs） suspensions were measured. SiO2 NPs with 10-20 nm diameters were found to be toxic. The 20% effective concentration （EC20） values for 72 and 96 hr were 388.1 and 216.5 mg/L, respectively. The contents of chlorophyll decreased significantly under moderate and high concentration （50, 100, and 200 mg/L） of SiO2 NPs after 96-hr exposure, but the carotenoids did not. SiO2 BPs were found to be nontoxic up to 200 mg/L. The toxicity of SiO2 NPs probablely due to their sorption to algal cells surface. The results imply that there is potential harm to aquatic environment by using SiO2 NPs, and it should deserve special concern.展开更多
In this article, the toxic effects of Enrofloxacin （ENFX） on Scenedesmus obliquus were studied, through investigating the growth, photosynthetic pigments, and protein contents. The possible toxic mechanisms of ENFX ...In this article, the toxic effects of Enrofloxacin （ENFX） on Scenedesmus obliquus were studied, through investigating the growth, photosynthetic pigments, and protein contents. The possible toxic mechanisms of ENFX were analyzed by determining the superoxide dismutase （SOD） activity, malondialdehyde （MDA） content, proline content, and superoxide anion （O2） generation rate. Results showed that the growth of algae was inhibited by ENFX and the 50% effective concentration （EC50） values for 24, 48, 72, and 96 h of ENFX were 88.39, 63.86, 45.10, and 59.16 mg .L^-1, respectively. After treated with ENFX for 96h, the contents of photosynthetic pigments decreased with the increase of ENFX concentration, the content of soluble protein and the activity of SOD increased and then decreased, and the generation rate of superoxide anion （O2^-） increased continually. The contents of MDA and proline changed little in lower ENFX concentration groups, but increased rapidly when treated with higher concentration groups. These results suggested that ENFX affected the growth ofS. obliquus, and the main toxicity mechanism was that algal cells generated the reactive oxygen species under ENFX stress, and then the reactive oxygen species （ROS） induced the oxidation damages of biologic macromolecules and changed the biomembrane permeability further.展开更多
In the microalgae harvesting process,which includes a step for dewatering the algal suspension,directly reusing extracted water in situ would decrease the freshwater footprint of cultivation systems.Among various alga...In the microalgae harvesting process,which includes a step for dewatering the algal suspension,directly reusing extracted water in situ would decrease the freshwater footprint of cultivation systems.Among various algae harvesting techniques,membrane-based filtration has shown numerous advantages.This study evaluated the reuse of permeate streams derived from Scenedesmus obliquus(S.obliquus)biomass filtration under bench-scale and pilot-scale conditions.In particular,this study identified a series of challenges and mechanisms that influence the water reuse potential and the robustness of the membrane harvesting system.In a preliminary phase of this investigation,the health status of the initial biomass was found to have important implications for the harvesting performance and quality of the permeate stream to be reused;healthy biomass ensured better dewatering performance(i.e.,higher water fluxes)and higher quality of the permeate water streams.A series of bench-scale filtration experiments with different combinations of cross-flow velocity and pressure values were performed to identify the operative conditions that would maximize water productivity.The selected conditions,2.4 m·s^(-1)and 1.4 bar(1 bar=105 Pa),respectively,were then applied to drive pilot-scale microfiltration tests to reuse the collected permeate as a new cultivation medium for S.obliquus growth in a pilot-scale photobioreactor.The investigation revealed key differences between the behavior of the membrane systems at the two scales(bench and pilot).It indicated the potential for beneficial reuse of the permeate stream as the pilot-scale experiments ensured high harvesting performance and growth rates of biomass in permeate water that were highly similar to those recorded in the ideal cultivation medium.Finally,different nutrient reintegration protocols were investigated,revealing that both macro-and micro-nutrient levels are critical for the success of the reuse approach.展开更多
采用YPMS-2生物光子测量仪检测栅藻的延迟发光。将测得的结果输入到Origin Pro 9.1软件中,与双曲线函数做最佳线性拟合并分析。栅藻有较强的生物光子辐射能力,其延迟发光的双曲线规律为生物光子辐射的相干性理论提供了证据。双曲函数拟...采用YPMS-2生物光子测量仪检测栅藻的延迟发光。将测得的结果输入到Origin Pro 9.1软件中,与双曲线函数做最佳线性拟合并分析。栅藻有较强的生物光子辐射能力,其延迟发光的双曲线规律为生物光子辐射的相干性理论提供了证据。双曲函数拟合出来的三个参数(I0、τ、β),携带着不同浓度栅藻和液体培养基的信息,即生物光子辐射对生物系统内部的变化及外界环境的影响有高度的敏感性,为栅藻可作为液体环境的生物指示剂,奠定了一定的理论基础。展开更多
为筛选高效复合溶藻菌群，分析了NP23、P25、Am11、混合菌a（NP23∶P25∶Am11＝1∶1∶1）、混合菌 b（NP23∶P25∶Am11＝3∶1∶1）和混合菌 c（NP23∶P25∶Am11＝1∶1∶3）对小球藻、栅藻、惠氏微囊藻、蛋白核小球藻和铜绿微囊藻的溶藻...为筛选高效复合溶藻菌群，分析了NP23、P25、Am11、混合菌a（NP23∶P25∶Am11＝1∶1∶1）、混合菌 b（NP23∶P25∶Am11＝3∶1∶1）和混合菌 c（NP23∶P25∶Am11＝1∶1∶3）对小球藻、栅藻、惠氏微囊藻、蛋白核小球藻和铜绿微囊藻的溶藻效果。结果表明：对于以小球藻为主体的富营养化水体，混合菌比单菌 Am11的溶藻效果低6％-14．1％；以栅藻、蛋白核小球藻、惠氏微囊藻和铜绿微囊藻为主体的富营养化水体，混合菌 b 和混合菌 a 比单菌 NP23、P25和 Am11的溶藻效果高7．2％-34．7％；混合菌 b 和混合菌 a 的溶藻效果都高于单菌，且在投菌后6 d 内的溶藻率都能达到90％以上。结论：混合菌对混合藻有较好的溶藻效果，可为混合溶藻菌剂的实际应用提供参考。展开更多
Sixteen Scenedesmus species or strains have been employed to investigate the maximum capacity of nickel (Ni) accumulation in 10 mg/L Ni solution. The results showed that the capacity of accumulating Ni from aqueou...Sixteen Scenedesmus species or strains have been employed to investigate the maximum capacity of nickel (Ni) accumulation in 10 mg/L Ni solution. The results showed that the capacity of accumulating Ni from aqueous solution in 16 Scenedesmus species or strains showed the diversity. S. quadricauda freshwater algae culture collection of the Institute of Hydrobiology (FACHB) 44 and S. quadricauda FACHB 506 performed much more capacity of Ni accumulation than other species such as Scenedesmus sp. FACHB 416 and Scenedesmus sp. FACHB 489. Sequestration of Ni ions from aqueous solution was very efficient (26.7 mg Ni/g dry weight, in the 100 mg/L Ni solution) in S. quadricauda FACHB 44. The kinetics of Ni binding indicated that Ni bioaccumulation, in algal cell of S. quadricauda FACHB 44, possessed a rapid biosorption (5 min) and an slow bioaccumulation (2-3 h). More than 70% of Ni binding in algal cell were accumulated by biosorption and the remaining 20%-30% were bioaccumulated by energy_consumed transportation. It is much more higher ratio of energy_consumed transportation in S. quadricauda FACHB 44 than in other algae. Both the transmission electron microscope (TEM) and the energy_dispersive X_ray (EDX) microanalyses also revealed the different mechanisms of bioaccumulation in the various subcellular regions: a very fast adsorption in the cell wall; and a time_dependent absorption in protoplasm, specially in starch and chromatin.展开更多
基金supported by the National Key Technologies R&D Programs of China (No.2006BAI19B05,2006BAJ02A10)
文摘To assess the aquatic ecosystem safety for silica （SiO2） nanoparticles （NPs）, the growth inhibition and photosynthetic pigment contents of Scenedesmus obliquus in logarithm growth phase exposed to SiO2 NPs and SiO2 bulk particles （BPs） suspensions were measured. SiO2 NPs with 10-20 nm diameters were found to be toxic. The 20% effective concentration （EC20） values for 72 and 96 hr were 388.1 and 216.5 mg/L, respectively. The contents of chlorophyll decreased significantly under moderate and high concentration （50, 100, and 200 mg/L） of SiO2 NPs after 96-hr exposure, but the carotenoids did not. SiO2 BPs were found to be nontoxic up to 200 mg/L. The toxicity of SiO2 NPs probablely due to their sorption to algal cells surface. The results imply that there is potential harm to aquatic environment by using SiO2 NPs, and it should deserve special concern.
文摘In this article, the toxic effects of Enrofloxacin （ENFX） on Scenedesmus obliquus were studied, through investigating the growth, photosynthetic pigments, and protein contents. The possible toxic mechanisms of ENFX were analyzed by determining the superoxide dismutase （SOD） activity, malondialdehyde （MDA） content, proline content, and superoxide anion （O2） generation rate. Results showed that the growth of algae was inhibited by ENFX and the 50% effective concentration （EC50） values for 24, 48, 72, and 96 h of ENFX were 88.39, 63.86, 45.10, and 59.16 mg .L^-1, respectively. After treated with ENFX for 96h, the contents of photosynthetic pigments decreased with the increase of ENFX concentration, the content of soluble protein and the activity of SOD increased and then decreased, and the generation rate of superoxide anion （O2^-） increased continually. The contents of MDA and proline changed little in lower ENFX concentration groups, but increased rapidly when treated with higher concentration groups. These results suggested that ENFX affected the growth ofS. obliquus, and the main toxicity mechanism was that algal cells generated the reactive oxygen species under ENFX stress, and then the reactive oxygen species （ROS） induced the oxidation damages of biologic macromolecules and changed the biomembrane permeability further.
基金supported by the Politecnico di Torino and the CleanWaterCenter@PoliTo(58_DIM20TIRALB,58_DIM22TIRALB,and 01_TRIN_CI_CWC).
文摘In the microalgae harvesting process,which includes a step for dewatering the algal suspension,directly reusing extracted water in situ would decrease the freshwater footprint of cultivation systems.Among various algae harvesting techniques,membrane-based filtration has shown numerous advantages.This study evaluated the reuse of permeate streams derived from Scenedesmus obliquus(S.obliquus)biomass filtration under bench-scale and pilot-scale conditions.In particular,this study identified a series of challenges and mechanisms that influence the water reuse potential and the robustness of the membrane harvesting system.In a preliminary phase of this investigation,the health status of the initial biomass was found to have important implications for the harvesting performance and quality of the permeate stream to be reused;healthy biomass ensured better dewatering performance(i.e.,higher water fluxes)and higher quality of the permeate water streams.A series of bench-scale filtration experiments with different combinations of cross-flow velocity and pressure values were performed to identify the operative conditions that would maximize water productivity.The selected conditions,2.4 m·s^(-1)and 1.4 bar(1 bar=105 Pa),respectively,were then applied to drive pilot-scale microfiltration tests to reuse the collected permeate as a new cultivation medium for S.obliquus growth in a pilot-scale photobioreactor.The investigation revealed key differences between the behavior of the membrane systems at the two scales(bench and pilot).It indicated the potential for beneficial reuse of the permeate stream as the pilot-scale experiments ensured high harvesting performance and growth rates of biomass in permeate water that were highly similar to those recorded in the ideal cultivation medium.Finally,different nutrient reintegration protocols were investigated,revealing that both macro-and micro-nutrient levels are critical for the success of the reuse approach.
文摘采用YPMS-2生物光子测量仪检测栅藻的延迟发光。将测得的结果输入到Origin Pro 9.1软件中,与双曲线函数做最佳线性拟合并分析。栅藻有较强的生物光子辐射能力,其延迟发光的双曲线规律为生物光子辐射的相干性理论提供了证据。双曲函数拟合出来的三个参数(I0、τ、β),携带着不同浓度栅藻和液体培养基的信息,即生物光子辐射对生物系统内部的变化及外界环境的影响有高度的敏感性,为栅藻可作为液体环境的生物指示剂,奠定了一定的理论基础。
文摘为筛选高效复合溶藻菌群，分析了NP23、P25、Am11、混合菌a（NP23∶P25∶Am11＝1∶1∶1）、混合菌 b（NP23∶P25∶Am11＝3∶1∶1）和混合菌 c（NP23∶P25∶Am11＝1∶1∶3）对小球藻、栅藻、惠氏微囊藻、蛋白核小球藻和铜绿微囊藻的溶藻效果。结果表明：对于以小球藻为主体的富营养化水体，混合菌比单菌 Am11的溶藻效果低6％-14．1％；以栅藻、蛋白核小球藻、惠氏微囊藻和铜绿微囊藻为主体的富营养化水体，混合菌 b 和混合菌 a 比单菌 NP23、P25和 Am11的溶藻效果高7．2％-34．7％；混合菌 b 和混合菌 a 的溶藻效果都高于单菌，且在投菌后6 d 内的溶藻率都能达到90％以上。结论：混合菌对混合藻有较好的溶藻效果，可为混合溶藻菌剂的实际应用提供参考。
文摘Sixteen Scenedesmus species or strains have been employed to investigate the maximum capacity of nickel (Ni) accumulation in 10 mg/L Ni solution. The results showed that the capacity of accumulating Ni from aqueous solution in 16 Scenedesmus species or strains showed the diversity. S. quadricauda freshwater algae culture collection of the Institute of Hydrobiology (FACHB) 44 and S. quadricauda FACHB 506 performed much more capacity of Ni accumulation than other species such as Scenedesmus sp. FACHB 416 and Scenedesmus sp. FACHB 489. Sequestration of Ni ions from aqueous solution was very efficient (26.7 mg Ni/g dry weight, in the 100 mg/L Ni solution) in S. quadricauda FACHB 44. The kinetics of Ni binding indicated that Ni bioaccumulation, in algal cell of S. quadricauda FACHB 44, possessed a rapid biosorption (5 min) and an slow bioaccumulation (2-3 h). More than 70% of Ni binding in algal cell were accumulated by biosorption and the remaining 20%-30% were bioaccumulated by energy_consumed transportation. It is much more higher ratio of energy_consumed transportation in S. quadricauda FACHB 44 than in other algae. Both the transmission electron microscope (TEM) and the energy_dispersive X_ray (EDX) microanalyses also revealed the different mechanisms of bioaccumulation in the various subcellular regions: a very fast adsorption in the cell wall; and a time_dependent absorption in protoplasm, specially in starch and chromatin.
