Pavlova sp.is not only one of the most popular microalgae in aquaculture,but also a source of high-quality biodiesel feedstock.With white light as a control(W),Pavlova sp.was cultured in this study under varying light...Pavlova sp.is not only one of the most popular microalgae in aquaculture,but also a source of high-quality biodiesel feedstock.With white light as a control(W),Pavlova sp.was cultured in this study under varying light quality,including monochromatic red light(R),blue light(B),and combinations thereof with different proportions(illuminators of m Rn B,comprised of m red light units and n blue ones,m+n=7),to examine the effects of illuminating light quality on biocomponent production and biodiesel quality.The results show that combined monochromatic light,especially 2R5B,3R4B,4R3B,and 5R2B,could improve the growth of Pavlova sp.The dry weight of harvested algae powder in the 5R2B group reached 418.03 mg/L,and was 22.65%higher than that in the control group(W).Lipid production under combined monochromatic light of 4R3B reached 107.86 mg/L,and was 25.61%higher than in the control(W).In addition,illumination using 4R3B increased the proportion of C16∶0(palmitic acid)and C16:1(palmitoleic acid)fatty acids in Pavlova sp.by 15.55%and 21.94%,respectively,which translates into improved biodiesel quality.All cetane numbers(CN)for 4R3B–6R1B were over 51,while iodine values(IV)and degrees of unsaturation(DU)were reduced,leading to more stable biodiesel suitable for longterm storage.In addition,protein production under 6R1B was as high as 31.56 mg/L,1.8 times greater than under W.Light quality is proposed as an effective tool to regulate biocomponent production by microalgae.展开更多
Pollution of marine environment has become an issue of major concern in recent years. Serious environmental pollution by heavy metals results from their increasing utilization in industrial processes and because most ...Pollution of marine environment has become an issue of major concern in recent years. Serious environmental pollution by heavy metals results from their increasing utilization in industrial processes and because most heavy metals are transported into the marine environment and accumulated without decomposition. The aim of the present study is to investigate the effects on growth, pigments, lipid peroxidation, and some antioxidant enzyme activities of marine microalga Pavlova viridis, in response to elevated concentrations of cobalt （Co） and manganese （Mn）, especially with regard to the involvement of antioxidative defences against heavy metal-induced oxidative stress. In response to Co^2＋, lipid peroxidation was enhanced compared to the control, as an indication of the oxidative damage caused by metal concentration assayed in the microalgal cells but not Mn^2＋. Exposure of Pavlova viridis to the two metals caused changes in enzyme activities in a different manner, depending on the metal assayed： after Co^2＋ treatments, total superoxide dismutase （SOD） activity was irregular, although it was not significantly affected by Mn^2＋ exposure. Co^2＋ and Mn^2＋ stimulated the activities of catalase （CAT） and glutathione （GSH）, whereas, glutathione peroxidase （GPX） showed a remarkable increase in activity in response to Co^2＋ treatments and decreased gradually with Mn^2＋ concentration, up to 50 μmol/L, and then rose very rapidly, reaching to about 38.98% at 200 μmol/L Mn^2＋. These results suggest that an activation of some antioxidant enzymes was enhanced, to counteract the oxidative stress induced by the two metals at higher concentration.展开更多
One strain of unicellular flagellated yellow-green algae was successlully isolated lrom the coastal area near Tianjin in the Bohai Sea in May 2015. The strain ranged from round to elongated in shape. Most of the cells...One strain of unicellular flagellated yellow-green algae was successlully isolated lrom the coastal area near Tianjin in the Bohai Sea in May 2015. The strain ranged from round to elongated in shape. Most of the cells possessed active motility, and some cells formed non-motile aggregation. Based on evidences from morphology, ultrastructure and molecular analysis, we identified the strain as Pavlova pinguis which belonged to Pavlovophyceae, Haptophyta. For Pavlovophyceae, only Pavlova viridis （Diacronema viridis） was reported in China seas prior to this study and it played an important role in aquaculture. This is the first record of Pavlova pinguis in Chinese waters.展开更多
In this work,we report for the first time the in-situ catalytic pyrolysis of Pavlova sp.microalgae,which has been performed in a fixed-bed reactor in presence of Ce/Al2O3-based catalysts.The effects of pyrolysis param...In this work,we report for the first time the in-situ catalytic pyrolysis of Pavlova sp.microalgae,which has been performed in a fixed-bed reactor in presence of Ce/Al2O3-based catalysts.The effects of pyrolysis parameters,such as temperature and catalyst were studied on the products yield distribution and biooil composition,among others.Results showed that all catalysts increased the bio-oil yield with respect to the non-catalytic runs and reduced the O/C ratio from 0.69（Pavlova sp.）to 0.1–0.15,which is close to that of crude oil.In terms of bio-oil oxygen content,Mg Ce/Al2O3presented the best performance with a reduction of more than 30%,from 14.1 to 9.8 wt%,of the oxygen concentration in comparison with thermal pyrolysis.However,Ni Ce/Al2O3gave rise to the highest aliphatics/aromatics fractions.The elemental and gas analysis indicates that N was partially removed from the catalytic bio-oils in the gas phase in forms of NH3and HCN.展开更多
Pavlova viridis sp. nov. is described on the basis of light and electron microscope observations. The material was collected from the coast of Haiyang county of Shandong, China. It is characterized by 1) yellowish gre...Pavlova viridis sp. nov. is described on the basis of light and electron microscope observations. The material was collected from the coast of Haiyang county of Shandong, China. It is characterized by 1) yellowish green to green chloroplast, 2) rudimentary short flagellum 0. 3um long and hook-shaped, 3)long flagellum with small spherical knob-scales, 4) absence of pyrenoid and stigma, and 5) marine habitat. This new species and P . salina seem to be most closely related to each other but their colour, the insertion of their three appendages, the shape of their knob scales, and their cell periplasts are quite different from one another .展开更多
Experiments of co-culture with Pavlova viridis and Tetraselmis tetrethele were carried out. Results showed a transparent phenomenon of interspecific competition between them. The competition was identified as an explo...Experiments of co-culture with Pavlova viridis and Tetraselmis tetrethele were carried out. Results showed a transparent phenomenon of interspecific competition between them. The competition was identified as an exploitation type through analysis. In the co-culture, both the growth rate (r) and the carrying capacity (K) of two species were affected, with a greater influence on P. viridis than on T. tetrethele,according to the comparision with those from the pure culture of two species. Each of interspecific competitive parameters of one species to the other was calculated,and the results showed that T.tetrethele possessed a more interspecific competitive capacity. Meanwhile, under the co-culture condition, both of the carrying capacity of two species were closely related to their respective inoculation density.The growth rate of P. viridis was in a positive proportion to its inoculation density, while a negative one existed in T. tetrethele.展开更多
基金Supported by the National Natural Science Foundation of China (Nos.42177459,41776156,41271521)。
文摘Pavlova sp.is not only one of the most popular microalgae in aquaculture,but also a source of high-quality biodiesel feedstock.With white light as a control(W),Pavlova sp.was cultured in this study under varying light quality,including monochromatic red light(R),blue light(B),and combinations thereof with different proportions(illuminators of m Rn B,comprised of m red light units and n blue ones,m+n=7),to examine the effects of illuminating light quality on biocomponent production and biodiesel quality.The results show that combined monochromatic light,especially 2R5B,3R4B,4R3B,and 5R2B,could improve the growth of Pavlova sp.The dry weight of harvested algae powder in the 5R2B group reached 418.03 mg/L,and was 22.65%higher than that in the control group(W).Lipid production under combined monochromatic light of 4R3B reached 107.86 mg/L,and was 25.61%higher than in the control(W).In addition,illumination using 4R3B increased the proportion of C16∶0(palmitic acid)and C16:1(palmitoleic acid)fatty acids in Pavlova sp.by 15.55%and 21.94%,respectively,which translates into improved biodiesel quality.All cetane numbers(CN)for 4R3B–6R1B were over 51,while iodine values(IV)and degrees of unsaturation(DU)were reduced,leading to more stable biodiesel suitable for longterm storage.In addition,protein production under 6R1B was as high as 31.56 mg/L,1.8 times greater than under W.Light quality is proposed as an effective tool to regulate biocomponent production by microalgae.
基金Project supported by the Natural Science Foundation of Jiangsu Province(No.95021301)China Postdoctoral Science Foundation(No.2005037121)Jiangsu Planned Projects for Postdoctoral Research Funds(No.0401001C)
文摘Pollution of marine environment has become an issue of major concern in recent years. Serious environmental pollution by heavy metals results from their increasing utilization in industrial processes and because most heavy metals are transported into the marine environment and accumulated without decomposition. The aim of the present study is to investigate the effects on growth, pigments, lipid peroxidation, and some antioxidant enzyme activities of marine microalga Pavlova viridis, in response to elevated concentrations of cobalt （Co） and manganese （Mn）, especially with regard to the involvement of antioxidative defences against heavy metal-induced oxidative stress. In response to Co^2＋, lipid peroxidation was enhanced compared to the control, as an indication of the oxidative damage caused by metal concentration assayed in the microalgal cells but not Mn^2＋. Exposure of Pavlova viridis to the two metals caused changes in enzyme activities in a different manner, depending on the metal assayed： after Co^2＋ treatments, total superoxide dismutase （SOD） activity was irregular, although it was not significantly affected by Mn^2＋ exposure. Co^2＋ and Mn^2＋ stimulated the activities of catalase （CAT） and glutathione （GSH）, whereas, glutathione peroxidase （GPX） showed a remarkable increase in activity in response to Co^2＋ treatments and decreased gradually with Mn^2＋ concentration, up to 50 μmol/L, and then rose very rapidly, reaching to about 38.98% at 200 μmol/L Mn^2＋. These results suggest that an activation of some antioxidant enzymes was enhanced, to counteract the oxidative stress induced by the two metals at higher concentration.
基金The National Natural Science Foundation of China under contract Nos 41876134,41676112 and 41276124the National Natural Science Foundation of Tianjin under contract No.17JCZDJC40000+2 种基金the University Innovation Team Training Program for Tianjin under contract No.TD12-5003the Exploration Program of Ocean with Science and Technology of Tianjin under contract No.KJXH2013-22the Changjiang Scholar Program of Chinese Ministry of Education of China to Jun Sun
文摘One strain of unicellular flagellated yellow-green algae was successlully isolated lrom the coastal area near Tianjin in the Bohai Sea in May 2015. The strain ranged from round to elongated in shape. Most of the cells possessed active motility, and some cells formed non-motile aggregation. Based on evidences from morphology, ultrastructure and molecular analysis, we identified the strain as Pavlova pinguis which belonged to Pavlovophyceae, Haptophyta. For Pavlovophyceae, only Pavlova viridis （Diacronema viridis） was reported in China seas prior to this study and it played an important role in aquaculture. This is the first record of Pavlova pinguis in Chinese waters.
基金the EPSRC (Grant no. EP/P018955/1) for supportthe financial support provided by the post-doctoral research fellowship programme (2219),Scientific and Technological Research Council of Turkey (TUBITAK)
文摘In this work,we report for the first time the in-situ catalytic pyrolysis of Pavlova sp.microalgae,which has been performed in a fixed-bed reactor in presence of Ce/Al2O3-based catalysts.The effects of pyrolysis parameters,such as temperature and catalyst were studied on the products yield distribution and biooil composition,among others.Results showed that all catalysts increased the bio-oil yield with respect to the non-catalytic runs and reduced the O/C ratio from 0.69（Pavlova sp.）to 0.1–0.15,which is close to that of crude oil.In terms of bio-oil oxygen content,Mg Ce/Al2O3presented the best performance with a reduction of more than 30%,from 14.1 to 9.8 wt%,of the oxygen concentration in comparison with thermal pyrolysis.However,Ni Ce/Al2O3gave rise to the highest aliphatics/aromatics fractions.The elemental and gas analysis indicates that N was partially removed from the catalytic bio-oils in the gas phase in forms of NH3and HCN.
文摘Pavlova viridis sp. nov. is described on the basis of light and electron microscope observations. The material was collected from the coast of Haiyang county of Shandong, China. It is characterized by 1) yellowish green to green chloroplast, 2) rudimentary short flagellum 0. 3um long and hook-shaped, 3)long flagellum with small spherical knob-scales, 4) absence of pyrenoid and stigma, and 5) marine habitat. This new species and P . salina seem to be most closely related to each other but their colour, the insertion of their three appendages, the shape of their knob scales, and their cell periplasts are quite different from one another .
文摘Experiments of co-culture with Pavlova viridis and Tetraselmis tetrethele were carried out. Results showed a transparent phenomenon of interspecific competition between them. The competition was identified as an exploitation type through analysis. In the co-culture, both the growth rate (r) and the carrying capacity (K) of two species were affected, with a greater influence on P. viridis than on T. tetrethele,according to the comparision with those from the pure culture of two species. Each of interspecific competitive parameters of one species to the other was calculated,and the results showed that T.tetrethele possessed a more interspecific competitive capacity. Meanwhile, under the co-culture condition, both of the carrying capacity of two species were closely related to their respective inoculation density.The growth rate of P. viridis was in a positive proportion to its inoculation density, while a negative one existed in T. tetrethele.
