In recent years, photosynthetic microalgae regained attention for biodiesel production. For efficient utilization of microalgae, a number of criteria including a strain with high biomass and lipid productivities and e...In recent years, photosynthetic microalgae regained attention for biodiesel production. For efficient utilization of microalgae, a number of criteria including a strain with high biomass and lipid productivities and employment of effective and reliable methods for oil extraction from the obtained biomass should be met. Recently, we have isolated and identified three thermo-resistant green microalgae strains, namely;Scenedesmus sp. ME02, Hindakia tetrachotoma ME03 and Mic-ractinium sp. ME05. In this study, we compared percent lipid content of thermos-tolerant mic-roalgal strains using the following solvent extraction methods: Soxhlet, Bligh and Dyer and Folch methods with or without assisted cell disruption techniques including lyophilization, homogenization, ultrasonication, bead and microwave-assisted. The highest increase in lipid yield was obtained with a combination of lyophilization and ultrasonication techniques together with Soxhlet method: 27% of total dry weight for Micractinium sp. ME05. We conclude that lyophilization and ultrasonication are effective assistance methods for lipid extraction from thermo-resistant microalgae.展开更多
Steam pretreatment was employed to disrupt Microalgal cells for lipids extraction.Effects of steam pretreatment on microstructure of microalgal cells were investigated through scanning electron microscopy(SEM)and tran...Steam pretreatment was employed to disrupt Microalgal cells for lipids extraction.Effects of steam pretreatment on microstructure of microalgal cells were investigated through scanning electron microscopy(SEM)and transmission electron microscopy(TEM).Effect of treatment on lipid extraction was also studied.Microalgal cell walls were distorted after steam pretreatment due to the hydrolysis of organic macromolecules contained in cell wall.Maximum curvature was increased from 1.88×10^(-6) m^(-1) to 1.43×10^(-7) m^(-1) after treatment with the steam at 130℃.The fractal dimension of microalgal cells increased from 1.25 to 1.30 after pretreatment for 15 min,and further increased to 1.47 when the pretreatment time was increased to 60 min.Increased steam pretreatment temperature and time enhanced the hydrolysis of organic macromolecules,and finally destroyed microalgal cell walls at pretreatment temperature of 130℃and pretreatment time of 60 min.Lipid extracted from wet microalgal was significantly increased(2.1-fold)after pretreatment.展开更多
Microalgae are widely used in the pharmaceutical and energy industries,therefore the conditions for their cultivation and extraction methods play an important role in the profiling and acquisition of lipids.The effici...Microalgae are widely used in the pharmaceutical and energy industries,therefore the conditions for their cultivation and extraction methods play an important role in the profiling and acquisition of lipids.The efficiency of lipid extraction from microalgae has attracted great interest from industry because of the wide variety of lipids and amounts that can be obtained.Acutodesmus obliquus(Scenedesmus obliquus UTEX 393)was used in this study.It was cultivated in Bold 3N medium modified with 75%nitrogen at 25℃,pH 6.8,125 r/min and a photoperiod of 18/6 h and illuminated with white light provided by a Light-Emitting Diode Surface Mount Device extensions(LED SMD)with an intensity of 1200μE/(m^(2)·s).The cells were stained with the Red Nile(RN)technique to indicate lipid production.Four extraction methods were compared,classical,microwave(MW),Soxhlet,and ultrasound(US),using the same solvent proportions(hexane:chloroform:methanol=1:2:3).All samples were analyzed with Fourier Transform Infrared Spectroscopy(FTIR)and Gas Chromatography coupled to Mass Spectrometry(GC-MS).The results showed:1)lipid production detected by RN was consistent with microalgal growth;2)the MW technique was the best extraction method,according to the statistical analysis through Randomized Complete Block(RCB)design and performance of 4.6%;and 3)the presence of saturated and unsaturated acids was indicated by FTIR spectra.GC-MS was able to identify palmitic and linoleic acids as the likely major constituents of the sample.展开更多
In this study,lipid extraction and CO_(2)capture are combined using N,N-dimethylcyclohexylamine(DMCHA)as switchable polarity solvent.The effects of operation parameters are discussed according to the CO_(2)absorption/...In this study,lipid extraction and CO_(2)capture are combined using N,N-dimethylcyclohexylamine(DMCHA)as switchable polarity solvent.The effects of operation parameters are discussed according to the CO_(2)absorption/desorption and lipid/DMCHA recovery results.A triphasic models considering lipid,water,and gas phases are established to analyze the kinetic behaviors.The results show that DMCHA is reversible through CO_(2)absorption/desorption,and the enhanced dispersion of droplets and bubbles in water phase improves the lipid/DMCHA recovery and CO_(2)absorption/desorption.The triphasic kinetic models fit well with experimental data,and gas-liquid mass transfer is regarded as the rate-determining step.The lower interfacial areas result in the poorer gas-liquid mass transfer for the DMCHA recovery than lipid recovery process.展开更多
In the current study,the potentiality and optimization of lipid extraction from secondary sludge for biodiesel production were investigated.Four lipid extraction parameters were examined and used for process optimizat...In the current study,the potentiality and optimization of lipid extraction from secondary sludge for biodiesel production were investigated.Four lipid extraction parameters were examined and used for process optimization and model development using Design of Experiment(DoE)method(namely methanol to hexane ratio-%,solvent to sludge ratio-ml/g,temperature-oC and extraction time-h).During the optimization process,free fatty acid(FFA)and saponifiable lipids(SLs)content of the extracted lipid were analyzed.The results revealed that,the maximum lipid extraction yield(Ylipid)predicted through numerically optimized conditions by the model for highest desirability(0.99)was 16.5%at methanol to hexane ratio(%)of 84%,solvent to sludge ratio(v/wt)of 45 ml/g,temperature at 90℃ for 6 hours extraction time.The extracted lipid contained a maximum amount of 31%(wt/wt)FFA,where palmatic acid was predominant.The FAMEs yield produced from ex-situ acid-catalyzed esterification/transesterification of the methanol-hexane co-solvent extracted lipid ranged between 4.5-5%(wt/wt)based on sludge weight.Fatty acid profile of FAMEs was found to be dominated by methyl palmitate(C16:0)representing 36%of FAMEs composition,followed by palmitoleic acid methyl ester(C16:1),oleic acid methyl ester(C18:1)and stearic acid methyl ester(C18:1)representing 24%,18%and 10%of the FFA composition respectively.PCA analysis showed that solvent to sludge ratio(ml/g)has the highest significant positive effect on FAMEs yield(p-value<0.05)where methanol to hexane ratio(X1),temperature(X3)and extraction time(X4)were inversely correlated with FAMEs yield.The results indicated the feasibility of using secondary sludge as an alternative feedstock for biodiesel production.However,the optimized conditions for maximizing extracted lipid content should not be considered suitable for FAMEs yield as well.展开更多
The aim of this study is to assess the antibacterial and anti-biofilm properties of the lipid extract from Man- tidis ootheca against the gentamycin resistant Pseudomonas aeruginosa. The chemical composition of the li...The aim of this study is to assess the antibacterial and anti-biofilm properties of the lipid extract from Man- tidis ootheca against the gentamycin resistant Pseudomonas aeruginosa. The chemical composition of the lipid extract and its relative proportion were determined using the technique of gas chromatography coupled with mass spec- trometry （GC-MS）. Antibacterial susceptibility tests were performed using a disc diffusion assay and the minimum inhibition concentration （MIC） was determined by way of the agar dilution method. The anti-biofilm test was carried out with crystal violet staining and scanning electron microscopy （SEM）. There were 16 compounds detected, and the most abundant components were sesquiterpenoids, monoterpenes, and trace aromatic compounds. The MIC for P. aeruginosa was 4 mg/ml and the eradication effect on preformed biofilms was established and compared with a ciprofloxacin control. The results of our study indicated that a lipid extract from M. ootheca could be used as a topical and antibacterial agent with anti-biofilm activity in the future.展开更多
Effects of nitrogen source and concentration as well as lipid extraction method on the lipid yield of autotrophic Scenedesmus dimorphus and heterotrophic Chlorella protothecoides were studied.Three concentration level...Effects of nitrogen source and concentration as well as lipid extraction method on the lipid yield of autotrophic Scenedesmus dimorphus and heterotrophic Chlorella protothecoides were studied.Three concentration levels of nitrate,urea and glycine/yeast extract as the nitrogen source were investigated.The highest lipid yield of S.dimorphus in the 17-d autotrophic culture was 0.40 g/L from the 1.8 g/L urea medium,and the maximum lipid yield of C.protothecoides in the nine-day heterotrophic culture was 5.89 g/L from the 2.4 g/L nitrate medium.Four different cell disruption methods-bead-beater,French press,sonication and wet milling-were studied for their effectiveness in solvent extraction of algal lipids from S.dimorphus and C.protothecoides.Wet milling followed by hexane extraction was most effective for S.dimorphus lipid extraction,whereas bead-beater disruption followed by hexane extraction was best for C.protothecoides.展开更多
Objective: Inflammation plays a critical role in atherosclerosis, and this inflammatory reaction is being intensively studied. Shenlian Extracts (参莲提取物), an active ingredient of Chinese medicinal herbs, is believ...Objective: Inflammation plays a critical role in atherosclerosis, and this inflammatory reaction is being intensively studied. Shenlian Extracts (参莲提取物), an active ingredient of Chinese medicinal herbs, is believed to have multiple therapeutic and preventive effects against human vascular diseases, including atherosclerosis. Our work investigated whether Shenlian Extracts serves as an anti-inflammatory agent during atherogenesis. Methods: We established a model of atherosclerosis in rabbits using balloon angioplasty and a high cholesterol diet. The effects of Shenlian Extracts on vessel structure and inflammation were assessed by hematoxylin-eosin staining of the femoral artery, measurement of inflammation-related factors in serum or vascular tissue, and radioimmunoassay. Enzyme linked immunosorbent assays (ELISA), flow cytometry and western blots were also performed. Results: We show that oral pre-treatment with Shenlian Extracts suppressed the pathological changes associated with atherosclerosis and that graded doses of Shenlian Extracts reduced total serum levels of cholesterol (90, 180 and 360 mg/kg), triglyceride (180 and 360 mg/kg), and LDL-c (90, 180 mg/kg). Various doses of Shenlian Extracts reduced serum content of TNF-α (180 and 360 mg/kg), CRP (90, 180 and 360 mg/kg) and IL-8 (360 mg/kg) (P<0.05), but led to no significant changes in IL-1β levels. Treatment with Shenlian Extracts also significantly reduced VCAM-1 levels (90 and 360 mg/kg) and IGF-1 levels (90 and 180 mg/kg) in vascular tissue but had no significant effect on ICAM-1 and MCP-1 levels. Finally, Shenlian Extracts significantly reduced the abnormal expression of CD18 in monocytes in a dose-dependent manner. Conclusion: These results suggest that Shenlian Extracts may play a direct role in preventing and treating atherogenesis by inhibiting the inflammatory reaction, providing insights into the possible mechanism underlying the anti-atherosclerotic actions of Shenlian Extracts.展开更多
文摘In recent years, photosynthetic microalgae regained attention for biodiesel production. For efficient utilization of microalgae, a number of criteria including a strain with high biomass and lipid productivities and employment of effective and reliable methods for oil extraction from the obtained biomass should be met. Recently, we have isolated and identified three thermo-resistant green microalgae strains, namely;Scenedesmus sp. ME02, Hindakia tetrachotoma ME03 and Mic-ractinium sp. ME05. In this study, we compared percent lipid content of thermos-tolerant mic-roalgal strains using the following solvent extraction methods: Soxhlet, Bligh and Dyer and Folch methods with or without assisted cell disruption techniques including lyophilization, homogenization, ultrasonication, bead and microwave-assisted. The highest increase in lipid yield was obtained with a combination of lyophilization and ultrasonication techniques together with Soxhlet method: 27% of total dry weight for Micractinium sp. ME05. We conclude that lyophilization and ultrasonication are effective assistance methods for lipid extraction from thermo-resistant microalgae.
基金supported by the National Key Research and Development Program-China(2017YFE0122800)Shandong Provincial Natural Science Foundation(ZR2019MC060)+1 种基金Key Research and Development Program of Jining City(2018ZDGH024)a Project of Shandong Province Higher Educational Science and Technology Program(J17KA095)。
文摘Steam pretreatment was employed to disrupt Microalgal cells for lipids extraction.Effects of steam pretreatment on microstructure of microalgal cells were investigated through scanning electron microscopy(SEM)and transmission electron microscopy(TEM).Effect of treatment on lipid extraction was also studied.Microalgal cell walls were distorted after steam pretreatment due to the hydrolysis of organic macromolecules contained in cell wall.Maximum curvature was increased from 1.88×10^(-6) m^(-1) to 1.43×10^(-7) m^(-1) after treatment with the steam at 130℃.The fractal dimension of microalgal cells increased from 1.25 to 1.30 after pretreatment for 15 min,and further increased to 1.47 when the pretreatment time was increased to 60 min.Increased steam pretreatment temperature and time enhanced the hydrolysis of organic macromolecules,and finally destroyed microalgal cell walls at pretreatment temperature of 130℃and pretreatment time of 60 min.Lipid extracted from wet microalgal was significantly increased(2.1-fold)after pretreatment.
文摘Microalgae are widely used in the pharmaceutical and energy industries,therefore the conditions for their cultivation and extraction methods play an important role in the profiling and acquisition of lipids.The efficiency of lipid extraction from microalgae has attracted great interest from industry because of the wide variety of lipids and amounts that can be obtained.Acutodesmus obliquus(Scenedesmus obliquus UTEX 393)was used in this study.It was cultivated in Bold 3N medium modified with 75%nitrogen at 25℃,pH 6.8,125 r/min and a photoperiod of 18/6 h and illuminated with white light provided by a Light-Emitting Diode Surface Mount Device extensions(LED SMD)with an intensity of 1200μE/(m^(2)·s).The cells were stained with the Red Nile(RN)technique to indicate lipid production.Four extraction methods were compared,classical,microwave(MW),Soxhlet,and ultrasound(US),using the same solvent proportions(hexane:chloroform:methanol=1:2:3).All samples were analyzed with Fourier Transform Infrared Spectroscopy(FTIR)and Gas Chromatography coupled to Mass Spectrometry(GC-MS).The results showed:1)lipid production detected by RN was consistent with microalgal growth;2)the MW technique was the best extraction method,according to the statistical analysis through Randomized Complete Block(RCB)design and performance of 4.6%;and 3)the presence of saturated and unsaturated acids was indicated by FTIR spectra.GC-MS was able to identify palmitic and linoleic acids as the likely major constituents of the sample.
基金supported by the Cooperation Fund of Sichuan University and The People’s Government of Yibin City(No.2020CDYB-34).
文摘In this study,lipid extraction and CO_(2)capture are combined using N,N-dimethylcyclohexylamine(DMCHA)as switchable polarity solvent.The effects of operation parameters are discussed according to the CO_(2)absorption/desorption and lipid/DMCHA recovery results.A triphasic models considering lipid,water,and gas phases are established to analyze the kinetic behaviors.The results show that DMCHA is reversible through CO_(2)absorption/desorption,and the enhanced dispersion of droplets and bubbles in water phase improves the lipid/DMCHA recovery and CO_(2)absorption/desorption.The triphasic kinetic models fit well with experimental data,and gas-liquid mass transfer is regarded as the rate-determining step.The lower interfacial areas result in the poorer gas-liquid mass transfer for the DMCHA recovery than lipid recovery process.
文摘In the current study,the potentiality and optimization of lipid extraction from secondary sludge for biodiesel production were investigated.Four lipid extraction parameters were examined and used for process optimization and model development using Design of Experiment(DoE)method(namely methanol to hexane ratio-%,solvent to sludge ratio-ml/g,temperature-oC and extraction time-h).During the optimization process,free fatty acid(FFA)and saponifiable lipids(SLs)content of the extracted lipid were analyzed.The results revealed that,the maximum lipid extraction yield(Ylipid)predicted through numerically optimized conditions by the model for highest desirability(0.99)was 16.5%at methanol to hexane ratio(%)of 84%,solvent to sludge ratio(v/wt)of 45 ml/g,temperature at 90℃ for 6 hours extraction time.The extracted lipid contained a maximum amount of 31%(wt/wt)FFA,where palmatic acid was predominant.The FAMEs yield produced from ex-situ acid-catalyzed esterification/transesterification of the methanol-hexane co-solvent extracted lipid ranged between 4.5-5%(wt/wt)based on sludge weight.Fatty acid profile of FAMEs was found to be dominated by methyl palmitate(C16:0)representing 36%of FAMEs composition,followed by palmitoleic acid methyl ester(C16:1),oleic acid methyl ester(C18:1)and stearic acid methyl ester(C18:1)representing 24%,18%and 10%of the FFA composition respectively.PCA analysis showed that solvent to sludge ratio(ml/g)has the highest significant positive effect on FAMEs yield(p-value<0.05)where methanol to hexane ratio(X1),temperature(X3)and extraction time(X4)were inversely correlated with FAMEs yield.The results indicated the feasibility of using secondary sludge as an alternative feedstock for biodiesel production.However,the optimized conditions for maximizing extracted lipid content should not be considered suitable for FAMEs yield as well.
文摘The aim of this study is to assess the antibacterial and anti-biofilm properties of the lipid extract from Man- tidis ootheca against the gentamycin resistant Pseudomonas aeruginosa. The chemical composition of the lipid extract and its relative proportion were determined using the technique of gas chromatography coupled with mass spec- trometry （GC-MS）. Antibacterial susceptibility tests were performed using a disc diffusion assay and the minimum inhibition concentration （MIC） was determined by way of the agar dilution method. The anti-biofilm test was carried out with crystal violet staining and scanning electron microscopy （SEM）. There were 16 compounds detected, and the most abundant components were sesquiterpenoids, monoterpenes, and trace aromatic compounds. The MIC for P. aeruginosa was 4 mg/ml and the eradication effect on preformed biofilms was established and compared with a ciprofloxacin control. The results of our study indicated that a lipid extract from M. ootheca could be used as a topical and antibacterial agent with anti-biofilm activity in the future.
基金the use of some equipment.This research is funded by NSF(Award CMMI-0836610)Kansas Agricultural Experiment Station(Contribution No.09-237-J from the Kansas Agricultural Experiment Station).
文摘Effects of nitrogen source and concentration as well as lipid extraction method on the lipid yield of autotrophic Scenedesmus dimorphus and heterotrophic Chlorella protothecoides were studied.Three concentration levels of nitrate,urea and glycine/yeast extract as the nitrogen source were investigated.The highest lipid yield of S.dimorphus in the 17-d autotrophic culture was 0.40 g/L from the 1.8 g/L urea medium,and the maximum lipid yield of C.protothecoides in the nine-day heterotrophic culture was 5.89 g/L from the 2.4 g/L nitrate medium.Four different cell disruption methods-bead-beater,French press,sonication and wet milling-were studied for their effectiveness in solvent extraction of algal lipids from S.dimorphus and C.protothecoides.Wet milling followed by hexane extraction was most effective for S.dimorphus lipid extraction,whereas bead-beater disruption followed by hexane extraction was best for C.protothecoides.
基金supported by grants of the National Natural Science Foundation of China (30973901)the Major Program for Technique Development Research of Novel Traditional Chinese Medicine Production (2009 ZX093 01-005- 2-4)+1 种基金the Autonomous Program of China Academy of Chinese Medical Sciences (ZZ20090207)the International S&T Cooperation Project (S2011ZR0193)
文摘Objective: Inflammation plays a critical role in atherosclerosis, and this inflammatory reaction is being intensively studied. Shenlian Extracts (参莲提取物), an active ingredient of Chinese medicinal herbs, is believed to have multiple therapeutic and preventive effects against human vascular diseases, including atherosclerosis. Our work investigated whether Shenlian Extracts serves as an anti-inflammatory agent during atherogenesis. Methods: We established a model of atherosclerosis in rabbits using balloon angioplasty and a high cholesterol diet. The effects of Shenlian Extracts on vessel structure and inflammation were assessed by hematoxylin-eosin staining of the femoral artery, measurement of inflammation-related factors in serum or vascular tissue, and radioimmunoassay. Enzyme linked immunosorbent assays (ELISA), flow cytometry and western blots were also performed. Results: We show that oral pre-treatment with Shenlian Extracts suppressed the pathological changes associated with atherosclerosis and that graded doses of Shenlian Extracts reduced total serum levels of cholesterol (90, 180 and 360 mg/kg), triglyceride (180 and 360 mg/kg), and LDL-c (90, 180 mg/kg). Various doses of Shenlian Extracts reduced serum content of TNF-α (180 and 360 mg/kg), CRP (90, 180 and 360 mg/kg) and IL-8 (360 mg/kg) (P<0.05), but led to no significant changes in IL-1β levels. Treatment with Shenlian Extracts also significantly reduced VCAM-1 levels (90 and 360 mg/kg) and IGF-1 levels (90 and 180 mg/kg) in vascular tissue but had no significant effect on ICAM-1 and MCP-1 levels. Finally, Shenlian Extracts significantly reduced the abnormal expression of CD18 in monocytes in a dose-dependent manner. Conclusion: These results suggest that Shenlian Extracts may play a direct role in preventing and treating atherogenesis by inhibiting the inflammatory reaction, providing insights into the possible mechanism underlying the anti-atherosclerotic actions of Shenlian Extracts.
