Coccolithophores have unique ability of dual carbon fixation(photosynthesis and biocalcification)and can accumulate bioactive compounds effectively,thereby showing huge potential for CO_(2) bioremediation and simultan...Coccolithophores have unique ability of dual carbon fixation(photosynthesis and biocalcification)and can accumulate bioactive compounds effectively,thereby showing huge potential for CO_(2) bioremediation and simultaneous production of valueadded substances.However,biotechnological exploration of these microalgae is still very limited.In order to develop efficient cultivation strategies of these organisms,we tested the abilities of Chrysotila roscoffensis,a coccolithophore,to grow under mixotrophic and heterotrophic cultivation conditions.It was confirmed that only glycerol stimulated the cell growth of this microalga in the presence of light.To study the physiological significance of mixotrophy,we conducted cell culture experiments both autotrophically and mixotrophically,the only difference of which was optimal amount of glycerol was added under mixotrophic conditions.The results showed that the addition of glycerol substantially enhanced the lipids and monounsaturated fatty acids accumulation of C.roscoffensis,but imposed slight influences on the photosynthetic capacity,pigments content,polyunsaturated fatty acids content,and biocalcification.We concluded that mixotrophy might be an appropriate strategy for exploration of this species for production of high value molecules.展开更多
While many harmful algal blooms have been associated with increasing eutrophication, not all species respond similarly and the increasing challenge, especially for resource managers, is to determine which blooms are r...While many harmful algal blooms have been associated with increasing eutrophication, not all species respond similarly and the increasing challenge, especially for resource managers, is to determine which blooms are related to eutrophication and to understand why particular species proliferate under specific nutrient conditions. The overall goal of this brief review is to describe why nutrient loads are not changing in stoichiometric proportion to the "Redfield ratio", and why this has important consequences for algal growth. Many types of harmful algae appear to be able to thrive, and/or increase their production of toxins, when nutrient loads are not in proportion classically identified as Redfield ratios. Here we also describe some of the physiological mechanisms of different species to take up nutrients and to thrive under conditions of nutrient imbalance.展开更多
The model diatom Phaeodactylum tricornutum is considered a promising source of various high value bioproducts,and developing cultivation processes is crucial for its commercialization.Although mixotrophy and heterotro...The model diatom Phaeodactylum tricornutum is considered a promising source of various high value bioproducts,and developing cultivation processes is crucial for its commercialization.Although mixotrophy and heterotrophy have been recommended as effective strategies for microalgal cultivation,previous studies on P.tricornutum have yielded conflicting results in terms of cultivating this microalga.To verify the capacity of this microalga utilizing external organic carbon,both heterotrophic and mixotrophic cultivation with varied carbon sources were performed using an axenic strain.The results demonstrate that glycerol was the only organic carbon that substantially stimulated the growth of P.tricornutum in the presence of light.Sodium acetate(NaAc)at low concentrations could also promote growth,while at high concentrations led to severe inhibition under mixotrophic conditions.The addition of glucose imposed no appreciable impact on either cell density or biomass concentration,confirming that P.tricornutum cannot metabolize external glucose.Subsequently,a comparative analysis between mixotrophy and autotrophy was performed to reveal the influences of glycerol on the cellular metabolism based on growth performances,biochemical compositions,and chlorophyll fluorescence parameters.Results also indicate that the addition of glycerol did not have detrimental effects on the capacity of either pigments biosynthesis or photosynthesis,but enhanced the saturated fatty acids and reduced the unsaturated fatty acids.展开更多
One isolate of Brachiomonas submarina was tested for its ability to grow heterotrophicly on 5 different organic compounds. Sodium acetate and glucose were found to be effective in supporting the growth. Sodium acetate...One isolate of Brachiomonas submarina was tested for its ability to grow heterotrophicly on 5 different organic compounds. Sodium acetate and glucose were found to be effective in supporting the growth. Sodium acetate was chosen as the organic nutrient to test the combined effects of organic and inorganic solutions on the growth and fatty acid composition of Brachiomonas submarina. The best growth rates were achieved at 3 mmol L -1 CH 3COONa and 0.88 mmol L -1 NaNO 3 in heterotrophic condition, and 4 mmol L -1 CH 3COONa and 3.52 mmol L -1 NaNO 3 in mixotrophic condition. The differences between fatty acid contents were significant. The total polyunsaturated fatty acids (T.P.U.F.As) varied from 55.79% to 67.72% in heteritrophic growth and from 52.39% to 65.55% in mixotrophic growth. It is concluded that CH 3COONa and NaNO 3 at 3 mmol L -1 and 3.52 mmol L -1 should respectively be used in order to achieve the highest growth rate and fatty acid content.展开更多
A possible source of biological material for the production of biodiesel is represented by microalgae, in particular by their lipid content. The aim of the present work was to optimize culture medium composition for i...A possible source of biological material for the production of biodiesel is represented by microalgae, in particular by their lipid content. The aim of the present work was to optimize culture medium composition for improving growth and lipid content of green microalgae Chlorella sorokiniana, Scenedesmus acuminatus and blue green Cyanobacterium aponicum. Lipids were quantitatively determined by spectrofluorometric method using Nile red flurometric stain. Initially, the effect of two different medium types, Bold’s and optimized culture medium (OCM), four types of carbon source (glucose and sodium acetate, molasses, glycerol, control) and four nitrogen concentrations (100%, -75%, -50%, -25%) on the enhancement of biomass and lipid content and lipid productivity were studied;indeed, optimized culture medium significantly improved growth, CDW for three microalgae, beside increasing lipid content and lipid productivity for S. acuminatus and C. aponicum by 7.5 and 5 folds respectively at 25th day compared to Bold’s medium. Moreover, 25% nitrogen deficient medium significantly increased lipid content and lipid productivity for both C. sorokiniana and C. aponicum at 2nd week of re-propagation to 10.6 and 2.6 folds over control (100% nitrogen). While S. acuminatus recorded the significant lipid content & productivity at 2nd week under recommended nitrogen dose in medium (100% N) by 4.4 folds over 25% deficient medium. Meanwhile 0.3% glycerol medium enhanced CDW, lipid content of S. acuminatus to 1.68 gL-1. While C. sorokiniana and C. aponicum recorded significant CDW under 0.3% acetate medium 1.37 and 0.76 gL-1. C. aponicum exhibited no growth under glycerol medium. The highest lipid content and lipid productivity were obtained under glycerol medium for C. sorokiniana and S. acuminatus (64.3 and 52.8 mg·g·gǃ·dǃ).展开更多
Blooms of Akashiwo sanguinea frequently break out around the world,causing huge economic losses to the aquaculture industry and seriously damaging coastal ecosystems.However,the formation mechanisms of A.sanguinea blo...Blooms of Akashiwo sanguinea frequently break out around the world,causing huge economic losses to the aquaculture industry and seriously damaging coastal ecosystems.However,the formation mechanisms of A.sanguinea blooms remain unclear.We investigated the allelopathic effects of A.sanguinea on multiple phytoplankton species,explored the mode of allelochemicals action and the way of nutrient factors regulation of the allelopathic activity.Results show that strains of A.sanguinea could inhibit the growth of co-occurring phytoplankton including Scrippsiella trochoidea,Phaeocystis globosa,and Rhodomonas salina,but inhibition of Prorocentrum micans was not obvious.The inhibition rates on phytoplankton were positively correlated with the cell densities of A.sanguinea.The highest inhibition rate of 94%on R.salina was for A.sanguinea CCMA256 culture of 2000 cells/mL at 72 h.We observed that cells of S.trochoidea,Ph.g lobosa,and R.sali na were lysed when co-cultured with A.sanguinea,with the shortest time for S.trochoidea.Additionally,the growth rates of A.sanguinea were promoted by coculturing with S.trochoidea,Ph.globosa,and R.salina.Four components of A.sanguinea culture were all able to inhibit growth of R.salina:the strongest inhibitory effect was found in the sonicated culture,followed by whole-cell culture,filtrates of sonicated culture,and filtrate culture.The crude extract of A.sanguinea culture also lysed cells of R.salina,and the inhibition rates on R.salina increased with the increasing dose of crude extract.It was shown that both nutrient enrichment and nitrogen:phosphorus ratio imbalance enhanced remarkably the allelopathic activity of A.sanguinea.The highest inhibition rate on R.salina of 70%occurred in A.sanguinea JX13 treatment at 2000 cells/mL under high nutrient condition in 48 h.In JX14 treatment at 2000 cells/mL for N:P of 10:1,the inhibition rate increased by 1.7 times of that for N:P of 20:1.In addition,the allelopathy of A.sanguinea could not only be a competitive strategy but also a nutrition strategy,playing an important role in formation and/or maintenance of blooms of the mixotrophic dinoflagellate A.sanguinea.展开更多
Marinisomatota(formerly recognized as Marinimicrobia,Marine Group A,and SAR406)are ubiquitous and abundant in marine environments,traditionally characterized as heterotrophic microorganisms.However,certain members of ...Marinisomatota(formerly recognized as Marinimicrobia,Marine Group A,and SAR406)are ubiquitous and abundant in marine environments,traditionally characterized as heterotrophic microorganisms.However,certain members of Mariniso-matota have demonstrated the capacity to harness light for carbon dioxide fixation and the synthesis of organic compounds,thriving in the translucent zone or transitioning between the translucent and aphotic layers.The metabolic strategies driv-ing the shift in trophic behaviors,and the factors influencing these transitions,remain largely unexplored.In this study,we investigate the metabolic strategies,ecological distribution,and dietary patterns of Marinisomatota through the analysis of metagenomic and metatranscriptomic data sourced from the global open oceans.A total of 1,588 Marinisomatota genomes were retrieved,representing one class,two orders,14 families,31 genera,and 67 species.These organisms are predomi-nantly found in low-latitude marine regions,with relative abundances ranging from 0.18 to 36.21%.Among the 14 families,S15-B10,TCS55,UBA1611,UBA2128,and UBA8226 exhibit potential for light-dependent processes associated with Crassulacean acid metabolism(M00169).Three distinct metabolic strategies were identified within Marinisomatota:MS0(photoautotrophic potential),MS1(heterotrophic with a pronounced glycolytic pathway),and MS2(heterotrophic without glycolysis).The emergence of these metabolic strategies may be a response to nutrient limitations within the ocean.This study reveals the potential for mixotrophic strategies in Marinisomatota,underscoring the critical interplay between life history traits and metabolic strategies in the evolution of novel nutritional groups.展开更多
In this study,an Artificial Neural Network-Genetic Algorithm(ANN-GA)approachwas successfully applied to optimise the physicochemical factors influencing the synthesis of unsaturated fatty acids(UFAs)in the microalgae ...In this study,an Artificial Neural Network-Genetic Algorithm(ANN-GA)approachwas successfully applied to optimise the physicochemical factors influencing the synthesis of unsaturated fatty acids(UFAs)in the microalgae P.kessleri UCM 001.The optimized model recommended specific cultivation conditions,including glucose at 29 g/L,NaNO_(3)at 2.4 g/L,K_(2)HPO_(4)at 0.4 g/L,red LED light,an intensity of 1000 lx,and an 8:16-h light-dark cycle.Through ANN-GA optimisation,a remarkable 66.79%increase in UFAs production in P.kessleri UCM 001 was achieved,compared to previous studies.This underscores the potential of this technology for enhancing valuable lipid production.Sequential variations in the application of physicochemical factors during microalgae culture under mixotrophic conditions,as optimized by ANN-GA,induced alterations in UFAs production and composition in P.kessleri UCM 001.This suggests the feasibility of tailoring the lipid profile of microalgae to obtain specific lipids for diverse industrial applications.Themicroalgaewere isolated froma high-mountain lake in Colombia,highlighting their adaptation to extreme conditions.This underscores their potential for sustainable lipid and biomaterial production.This study demonstrates the effectiveness of using ANN-GA technology to optimise UFAs production in microalgae,offering a promising avenue for obtaining valuable lipids.Themicroalgae's unique origin in a high-mountain environment in Colombia emphasises the importance of exploring and harnessing microbial resources in distinctive geographical regions for biotechnological applications.展开更多
基金supported by the Ningbo Science and Technology Project(No.2024J176)the Key Program of Science and Technology Innovation in Ningbo(No.2023 Z118)the Zhejiang Provincial Natural Science Foundation of China(No.LY22C190001)。
文摘Coccolithophores have unique ability of dual carbon fixation(photosynthesis and biocalcification)and can accumulate bioactive compounds effectively,thereby showing huge potential for CO_(2) bioremediation and simultaneous production of valueadded substances.However,biotechnological exploration of these microalgae is still very limited.In order to develop efficient cultivation strategies of these organisms,we tested the abilities of Chrysotila roscoffensis,a coccolithophore,to grow under mixotrophic and heterotrophic cultivation conditions.It was confirmed that only glycerol stimulated the cell growth of this microalga in the presence of light.To study the physiological significance of mixotrophy,we conducted cell culture experiments both autotrophically and mixotrophically,the only difference of which was optimal amount of glycerol was added under mixotrophic conditions.The results showed that the addition of glycerol substantially enhanced the lipids and monounsaturated fatty acids accumulation of C.roscoffensis,but imposed slight influences on the photosynthetic capacity,pigments content,polyunsaturated fatty acids content,and biocalcification.We concluded that mixotrophy might be an appropriate strategy for exploration of this species for production of high value molecules.
文摘While many harmful algal blooms have been associated with increasing eutrophication, not all species respond similarly and the increasing challenge, especially for resource managers, is to determine which blooms are related to eutrophication and to understand why particular species proliferate under specific nutrient conditions. The overall goal of this brief review is to describe why nutrient loads are not changing in stoichiometric proportion to the "Redfield ratio", and why this has important consequences for algal growth. Many types of harmful algae appear to be able to thrive, and/or increase their production of toxins, when nutrient loads are not in proportion classically identified as Redfield ratios. Here we also describe some of the physiological mechanisms of different species to take up nutrients and to thrive under conditions of nutrient imbalance.
基金Supported by the National Science and Technology Basic Resources Investigation Program of China(No.2018 FY100206)the National Natural Science Foundation of China(No.31902370)+1 种基金the Ningbo Public Welfare Science and Technology Program(No.2022S161)the Key Program of Science and Technology Innovation in Ningbo(No.2023Z118)。
文摘The model diatom Phaeodactylum tricornutum is considered a promising source of various high value bioproducts,and developing cultivation processes is crucial for its commercialization.Although mixotrophy and heterotrophy have been recommended as effective strategies for microalgal cultivation,previous studies on P.tricornutum have yielded conflicting results in terms of cultivating this microalga.To verify the capacity of this microalga utilizing external organic carbon,both heterotrophic and mixotrophic cultivation with varied carbon sources were performed using an axenic strain.The results demonstrate that glycerol was the only organic carbon that substantially stimulated the growth of P.tricornutum in the presence of light.Sodium acetate(NaAc)at low concentrations could also promote growth,while at high concentrations led to severe inhibition under mixotrophic conditions.The addition of glucose imposed no appreciable impact on either cell density or biomass concentration,confirming that P.tricornutum cannot metabolize external glucose.Subsequently,a comparative analysis between mixotrophy and autotrophy was performed to reveal the influences of glycerol on the cellular metabolism based on growth performances,biochemical compositions,and chlorophyll fluorescence parameters.Results also indicate that the addition of glycerol did not have detrimental effects on the capacity of either pigments biosynthesis or photosynthesis,but enhanced the saturated fatty acids and reduced the unsaturated fatty acids.
文摘One isolate of Brachiomonas submarina was tested for its ability to grow heterotrophicly on 5 different organic compounds. Sodium acetate and glucose were found to be effective in supporting the growth. Sodium acetate was chosen as the organic nutrient to test the combined effects of organic and inorganic solutions on the growth and fatty acid composition of Brachiomonas submarina. The best growth rates were achieved at 3 mmol L -1 CH 3COONa and 0.88 mmol L -1 NaNO 3 in heterotrophic condition, and 4 mmol L -1 CH 3COONa and 3.52 mmol L -1 NaNO 3 in mixotrophic condition. The differences between fatty acid contents were significant. The total polyunsaturated fatty acids (T.P.U.F.As) varied from 55.79% to 67.72% in heteritrophic growth and from 52.39% to 65.55% in mixotrophic growth. It is concluded that CH 3COONa and NaNO 3 at 3 mmol L -1 and 3.52 mmol L -1 should respectively be used in order to achieve the highest growth rate and fatty acid content.
文摘A possible source of biological material for the production of biodiesel is represented by microalgae, in particular by their lipid content. The aim of the present work was to optimize culture medium composition for improving growth and lipid content of green microalgae Chlorella sorokiniana, Scenedesmus acuminatus and blue green Cyanobacterium aponicum. Lipids were quantitatively determined by spectrofluorometric method using Nile red flurometric stain. Initially, the effect of two different medium types, Bold’s and optimized culture medium (OCM), four types of carbon source (glucose and sodium acetate, molasses, glycerol, control) and four nitrogen concentrations (100%, -75%, -50%, -25%) on the enhancement of biomass and lipid content and lipid productivity were studied;indeed, optimized culture medium significantly improved growth, CDW for three microalgae, beside increasing lipid content and lipid productivity for S. acuminatus and C. aponicum by 7.5 and 5 folds respectively at 25th day compared to Bold’s medium. Moreover, 25% nitrogen deficient medium significantly increased lipid content and lipid productivity for both C. sorokiniana and C. aponicum at 2nd week of re-propagation to 10.6 and 2.6 folds over control (100% nitrogen). While S. acuminatus recorded the significant lipid content & productivity at 2nd week under recommended nitrogen dose in medium (100% N) by 4.4 folds over 25% deficient medium. Meanwhile 0.3% glycerol medium enhanced CDW, lipid content of S. acuminatus to 1.68 gL-1. While C. sorokiniana and C. aponicum recorded significant CDW under 0.3% acetate medium 1.37 and 0.76 gL-1. C. aponicum exhibited no growth under glycerol medium. The highest lipid content and lipid productivity were obtained under glycerol medium for C. sorokiniana and S. acuminatus (64.3 and 52.8 mg·g·gǃ·dǃ).
基金Supported by the National Natural Science Foundation of China(NSFC)(Nos.41576159,41676099)。
文摘Blooms of Akashiwo sanguinea frequently break out around the world,causing huge economic losses to the aquaculture industry and seriously damaging coastal ecosystems.However,the formation mechanisms of A.sanguinea blooms remain unclear.We investigated the allelopathic effects of A.sanguinea on multiple phytoplankton species,explored the mode of allelochemicals action and the way of nutrient factors regulation of the allelopathic activity.Results show that strains of A.sanguinea could inhibit the growth of co-occurring phytoplankton including Scrippsiella trochoidea,Phaeocystis globosa,and Rhodomonas salina,but inhibition of Prorocentrum micans was not obvious.The inhibition rates on phytoplankton were positively correlated with the cell densities of A.sanguinea.The highest inhibition rate of 94%on R.salina was for A.sanguinea CCMA256 culture of 2000 cells/mL at 72 h.We observed that cells of S.trochoidea,Ph.g lobosa,and R.sali na were lysed when co-cultured with A.sanguinea,with the shortest time for S.trochoidea.Additionally,the growth rates of A.sanguinea were promoted by coculturing with S.trochoidea,Ph.globosa,and R.salina.Four components of A.sanguinea culture were all able to inhibit growth of R.salina:the strongest inhibitory effect was found in the sonicated culture,followed by whole-cell culture,filtrates of sonicated culture,and filtrate culture.The crude extract of A.sanguinea culture also lysed cells of R.salina,and the inhibition rates on R.salina increased with the increasing dose of crude extract.It was shown that both nutrient enrichment and nitrogen:phosphorus ratio imbalance enhanced remarkably the allelopathic activity of A.sanguinea.The highest inhibition rate on R.salina of 70%occurred in A.sanguinea JX13 treatment at 2000 cells/mL under high nutrient condition in 48 h.In JX14 treatment at 2000 cells/mL for N:P of 10:1,the inhibition rate increased by 1.7 times of that for N:P of 20:1.In addition,the allelopathy of A.sanguinea could not only be a competitive strategy but also a nutrition strategy,playing an important role in formation and/or maintenance of blooms of the mixotrophic dinoflagellate A.sanguinea.
基金supported by the National Natu-ral Science Foundation of China(Grant No.42030412,42206101)Sci-entific Research Foundation of Third Institute of Oceanography,MNR(No.2023003,2019021).
文摘Marinisomatota(formerly recognized as Marinimicrobia,Marine Group A,and SAR406)are ubiquitous and abundant in marine environments,traditionally characterized as heterotrophic microorganisms.However,certain members of Mariniso-matota have demonstrated the capacity to harness light for carbon dioxide fixation and the synthesis of organic compounds,thriving in the translucent zone or transitioning between the translucent and aphotic layers.The metabolic strategies driv-ing the shift in trophic behaviors,and the factors influencing these transitions,remain largely unexplored.In this study,we investigate the metabolic strategies,ecological distribution,and dietary patterns of Marinisomatota through the analysis of metagenomic and metatranscriptomic data sourced from the global open oceans.A total of 1,588 Marinisomatota genomes were retrieved,representing one class,two orders,14 families,31 genera,and 67 species.These organisms are predomi-nantly found in low-latitude marine regions,with relative abundances ranging from 0.18 to 36.21%.Among the 14 families,S15-B10,TCS55,UBA1611,UBA2128,and UBA8226 exhibit potential for light-dependent processes associated with Crassulacean acid metabolism(M00169).Three distinct metabolic strategies were identified within Marinisomatota:MS0(photoautotrophic potential),MS1(heterotrophic with a pronounced glycolytic pathway),and MS2(heterotrophic without glycolysis).The emergence of these metabolic strategies may be a response to nutrient limitations within the ocean.This study reveals the potential for mixotrophic strategies in Marinisomatota,underscoring the critical interplay between life history traits and metabolic strategies in the evolution of novel nutritional groups.
文摘In this study,an Artificial Neural Network-Genetic Algorithm(ANN-GA)approachwas successfully applied to optimise the physicochemical factors influencing the synthesis of unsaturated fatty acids(UFAs)in the microalgae P.kessleri UCM 001.The optimized model recommended specific cultivation conditions,including glucose at 29 g/L,NaNO_(3)at 2.4 g/L,K_(2)HPO_(4)at 0.4 g/L,red LED light,an intensity of 1000 lx,and an 8:16-h light-dark cycle.Through ANN-GA optimisation,a remarkable 66.79%increase in UFAs production in P.kessleri UCM 001 was achieved,compared to previous studies.This underscores the potential of this technology for enhancing valuable lipid production.Sequential variations in the application of physicochemical factors during microalgae culture under mixotrophic conditions,as optimized by ANN-GA,induced alterations in UFAs production and composition in P.kessleri UCM 001.This suggests the feasibility of tailoring the lipid profile of microalgae to obtain specific lipids for diverse industrial applications.Themicroalgaewere isolated froma high-mountain lake in Colombia,highlighting their adaptation to extreme conditions.This underscores their potential for sustainable lipid and biomaterial production.This study demonstrates the effectiveness of using ANN-GA technology to optimise UFAs production in microalgae,offering a promising avenue for obtaining valuable lipids.Themicroalgae's unique origin in a high-mountain environment in Colombia emphasises the importance of exploring and harnessing microbial resources in distinctive geographical regions for biotechnological applications.
