Pub Date : 2025-12-05DOI: 10.1016/j.algal.2025.104469
Emil Gundersen , Antoinette Kazbar , Iulian Z. Boboescu , Paul Kempen , Susan L. Holdt , Jette Jakobsen , Maria Barbosa , Charlotte Jacobsen
The microalga Nannochloropsis oceanica is a promising source of valuable nutrients such as protein, omega-3 fatty acids, and vitamins. Unfortunately, these compounds are protected by a tough cell wall that hampers digestibility. The present study evaluated bead milling for cell disruption of N. oceanica, with focus on biomass recovery, composition, and in vitro bioaccessibility. Suspensions of lyophilized biomass were subjected to different milling severities while determining the disruption level and dry matter recovery. The concentration of amino acids, fatty acids, and vitamin K were determined before and after milling. Potential changes in vitamin K and fatty acid bioaccessibility were assessed using the INFOGEST 2.0 model, complemented with visual observations using scanning electron microscopy. With the chosen milling parameters (agitator speeds 6 m·s−1 and 12 m·s−1 + treatment times 1.0, 2.5, 5.0 min), 20–70 % cell disruption was achieved. Dry matter recovery decreased from 100 % (non-disrupted) to 69 % for the most disrupted sample. Bead milling showed no significant impact on the concentration of total amino acids, total fatty acids, EPA, and MK-4. These components remained relatively stable at 310–330 mg AA·g−1 DM, 210–240 mg FA·g−1 DM, 23–28 mg EPA·g−1 DM, and 70–85 μg MK-4·g−1 DM. Bead milling did not significantly influence the bioaccessibility of EPA and MK-4, which remained anchored at 8–12 %, despite clear structural alterations in the processed biomass. The results verify bead milling as an effective cell disruption method for N. oceanica but also indicate that this alone does not ensure improved in vitro bioaccessibility of intracellular nutrients.
{"title":"Cell disruption of microalga Nannochloropsis oceanica using bead milling: Effect on recovery, composition, and bioaccessibility of partially disrupted biomass","authors":"Emil Gundersen , Antoinette Kazbar , Iulian Z. Boboescu , Paul Kempen , Susan L. Holdt , Jette Jakobsen , Maria Barbosa , Charlotte Jacobsen","doi":"10.1016/j.algal.2025.104469","DOIUrl":"10.1016/j.algal.2025.104469","url":null,"abstract":"<div><div>The microalga <em>Nannochloropsis oceanica</em> is a promising source of valuable nutrients such as protein, omega-3 fatty acids, and vitamins. Unfortunately, these compounds are protected by a tough cell wall that hampers digestibility. The present study evaluated bead milling for cell disruption of <em>N. oceanica</em>, with focus on biomass recovery, composition, and <em>in vitro</em> bioaccessibility. Suspensions of lyophilized biomass were subjected to different milling severities while determining the disruption level and dry matter recovery. The concentration of amino acids, fatty acids, and vitamin K were determined before and after milling. Potential changes in vitamin K and fatty acid bioaccessibility were assessed using the INFOGEST 2.0 model, complemented with visual observations using scanning electron microscopy. With the chosen milling parameters (agitator speeds 6 m·s<sup>−1</sup> and 12 m·s<sup>−1</sup> + treatment times 1.0, 2.5, 5.0 min), 20–70 % cell disruption was achieved. Dry matter recovery decreased from 100 % (non-disrupted) to 69 % for the most disrupted sample. Bead milling showed no significant impact on the concentration of total amino acids, total fatty acids, EPA, and MK-4. These components remained relatively stable at 310–330 mg AA·g<sup>−1</sup> DM, 210–240 mg FA·g<sup>−1</sup> DM, 23–28 mg EPA·g<sup>−1</sup> DM, and 70–85 μg MK-4·g<sup>−1</sup> DM. Bead milling did not significantly influence the bioaccessibility of EPA and MK-4, which remained anchored at 8–12 %, despite clear structural alterations in the processed biomass. The results verify bead milling as an effective cell disruption method for <em>N. oceanica</em> but also indicate that this alone does not ensure improved <em>in vitro</em> bioaccessibility of intracellular nutrients.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"93 ","pages":"Article 104469"},"PeriodicalIF":4.5,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-04DOI: 10.1016/j.algal.2025.104457
Xin Li , Lu Zhou , Wenting Yang , Hong Wang , Xuehua Liu , Songcui Wu , Wenhui Gu , Lijun Wang , Xiujun Xie , Senjie Lin , Qiang Hu , Shan Gao , Guangce Wang
Global warming threatens the productivity and diversity of marine diatoms which are responsible for 20 % of global primary productivity. However, the molecular mechanisms behind their adaptation to high temperature are poorly understood. Here, we found that the genes encoding COP9 signalosome (CSN) subunits are widely distributed in marine phytoplankton particularly diatoms, and CSN2 is the most conserved subunit which plays an important role in the adaptation of marine diatoms to high temperature. Moreover, we found CSN2 mutants of the model diatom Phaeodactylum tricornutum exhibited the decline of growth at high temperatures (25 °C) and decrease of the tolerance to ultraviolet radiation. The deletion mutation of CSN2 also caused alteration of P. tricornutum cell shape. Furthermore, integrated ubiquitylomic and proteomic analyses of CSN2 mutant of P. tricornutum revealed that as a scaffold, CSN2 regulated the ubiquitination levels of proteins mainly including heat shock proteins, ribosomal proteins, and histones. All these results suggested that CSN2 played a critical role in P. tricornutum high temperature adaptation by regulating protein ubiquitination.
{"title":"CSN2 of COP9 signalosome underpins high temperature adaptation of the diatom Phaeodactylum tricornutum through regulating protein ubiquitination","authors":"Xin Li , Lu Zhou , Wenting Yang , Hong Wang , Xuehua Liu , Songcui Wu , Wenhui Gu , Lijun Wang , Xiujun Xie , Senjie Lin , Qiang Hu , Shan Gao , Guangce Wang","doi":"10.1016/j.algal.2025.104457","DOIUrl":"10.1016/j.algal.2025.104457","url":null,"abstract":"<div><div>Global warming threatens the productivity and diversity of marine diatoms which are responsible for 20 % of global primary productivity. However, the molecular mechanisms behind their adaptation to high temperature are poorly understood. Here, we found that the genes encoding COP9 signalosome (CSN) subunits are widely distributed in marine phytoplankton particularly diatoms, and CSN2 is the most conserved subunit which plays an important role in the adaptation of marine diatoms to high temperature. Moreover, we found <em>CSN2</em> mutants of the model diatom <em>Phaeodactylum tricornutum</em> exhibited the decline of growth at high temperatures (25 °C) and decrease of the tolerance to ultraviolet radiation. The deletion mutation of <em>CSN</em>2 also caused alteration of <em>P. tricornutum</em> cell shape. Furthermore, integrated ubiquitylomic and proteomic analyses of <em>CSN2</em> mutant of <em>P. tricornutum</em> revealed that as a scaffold, CSN2 regulated the ubiquitination levels of proteins mainly including heat shock proteins, ribosomal proteins, and histones. All these results suggested that CSN2 played a critical role in <em>P. tricornutum</em> high temperature adaptation by regulating protein ubiquitination.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"93 ","pages":"Article 104457"},"PeriodicalIF":4.5,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145786525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-04DOI: 10.1016/j.algal.2025.104461
Sakhi Ghelichi , David Julian McClements , Ann-Dorit Moltke Sørensen , Charlotte Jacobsen
Seaweed extracts were obtained using a three-step extraction procedure involving pretreating Palmaria palmata in aqueous solutions of pH 3, 6, and 9, followed by sequential enzymatic/alkaline extractions. The extracts (Ext−3, Ext−6, Ext−9) obtained were characterized by measuring their protein, phenolic, and carbohydrate contents, as well as their degree of hydrolysis (DH), in vitro antioxidant activities, and dynamic interfacial tensions. Moreover, the effects on the physical and chemical stability of 5 % microalgal oil-in-water nanoemulsions were evaluated over 21 days. There were no significant differences in the droplet size of the nanoemulsions stabilized by the three extracts (p = 0.762–1.000). Additionally, Turbiscan analysis indicated that the nanoemulsions remained physically stable at the end of the storage period. Red seaweed extracts inhibited oxidation, with peroxide values of <10 meq/kg oil, compared to >20 meq/kg oil in the control nanoemulsion at Day 21. The control nanoemulsion had high levels of volatile oxidation compounds, including 1-penten-3-ol (4230 ± 200 ng/g), (E,E)-2,4-heptadienal (3110 ± 120 ng/g), and 2-ethylfuran (2400 ± 180 ng/g). The addition of the seaweed extracts significantly reduced the concentrations of these volatile compounds (p < 0.0001). These results suggest that seaweed extracts can be used as natural antioxidants in emulsified food products.
{"title":"Omega-3 microalgal oil-in-water nanoemulsions stabilized by red seaweed extracts: Physical and oxidative stability","authors":"Sakhi Ghelichi , David Julian McClements , Ann-Dorit Moltke Sørensen , Charlotte Jacobsen","doi":"10.1016/j.algal.2025.104461","DOIUrl":"10.1016/j.algal.2025.104461","url":null,"abstract":"<div><div>Seaweed extracts were obtained using a three-step extraction procedure involving pretreating <em>Palmaria palmata</em> in aqueous solutions of pH 3, 6, and 9, followed by sequential enzymatic/alkaline extractions. The extracts (Ext<sub>−</sub><sub>3</sub>, Ext<sub>−</sub><sub>6</sub>, Ext<sub>−</sub><sub>9</sub>) obtained were characterized by measuring their protein, phenolic, and carbohydrate contents, as well as their degree of hydrolysis (DH), <em>in vitro</em> antioxidant activities, and dynamic interfacial tensions. Moreover, the effects on the physical and chemical stability of 5 % microalgal oil-in-water nanoemulsions were evaluated over 21 days. There were no significant differences in the droplet size of the nanoemulsions stabilized by the three extracts (<em>p</em> = 0.762–1.000). Additionally, Turbiscan analysis indicated that the nanoemulsions remained physically stable at the end of the storage period. Red seaweed extracts inhibited oxidation, with peroxide values of <10 meq/kg oil, compared to >20 meq/kg oil in the control nanoemulsion at Day 21. The control nanoemulsion had high levels of volatile oxidation compounds, including 1-penten-3-ol (4230 ± 200 ng/g), (<em>E,E</em>)-2,4-heptadienal (3110 ± 120 ng/g), and 2-ethylfuran (2400 ± 180 ng/g). The addition of the seaweed extracts significantly reduced the concentrations of these volatile compounds (<em>p</em> < 0.0001). These results suggest that seaweed extracts can be used as natural antioxidants in emulsified food products.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"93 ","pages":"Article 104461"},"PeriodicalIF":4.5,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145786527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-04DOI: 10.1016/j.algal.2025.104450
Paulina S. Birgersson , Alexander Mika Hannasvik , Finn L. Aachmann
Fucoidans are sulfated fucose-rich polysaccharides produced by brown algae. They are traditionally extracted using neutral or acidic solutions at elevated temperatures. Recently, enzyme-assisted extraction (EAE) has been proposed as an alternative approach to obtain high yields while preserving fucoidans' native structures. In previous studies, EAE has replaced chemical extraction to yield a single fucoidan fraction. In this study, a new sequential approach was developed: fucoidans were first extracted under mild chemical conditions, yielding a fraction referred to as ‘easily accessible fucoidans’, followed by EAE to obtain a fraction defined as ‘interconnected fucoidans’. The process was applied to Alaria esculenta (AE) and Saccharina latissima (SL). Compositional and structural analyses by CHNS-analysis, HPAEC-PAD, SEC-MALS, and NMR revealed distinct differences between the two fucoidan fractions, including variations in monosaccharide composition, sulfation, and acetylation degrees. These differences, along with the varying extraction conditions required, suggest that the fractions represent distinct fucoidan types. We hypothesize that the chemically extracted fucoidans are not covalently bound to any structures and originate from the thallus surface or outer cell wall layers of the algae, while the EAE extracted fucoidans are more tightly bound (either covalently linked or entangled) to other cell wall components. Furthermore, a fraction of fucoidans from AE appeared to be covalently linked to polyphenols, as identified and characterized by NMR. To our knowledge, this is the first study describing potential covalent linkages between fucoidan and polyphenols in brown algae.
{"title":"Sequential chemical and enzymatic extraction of fucoidans from brown algae yields distinct fucoidan types","authors":"Paulina S. Birgersson , Alexander Mika Hannasvik , Finn L. Aachmann","doi":"10.1016/j.algal.2025.104450","DOIUrl":"10.1016/j.algal.2025.104450","url":null,"abstract":"<div><div>Fucoidans are sulfated fucose-rich polysaccharides produced by brown algae. They are traditionally extracted using neutral or acidic solutions at elevated temperatures. Recently, enzyme-assisted extraction (EAE) has been proposed as an alternative approach to obtain high yields while preserving fucoidans' native structures. In previous studies, EAE has replaced chemical extraction to yield a single fucoidan fraction. In this study, a new sequential approach was developed: fucoidans were first extracted under mild chemical conditions, yielding a fraction referred to as ‘easily accessible fucoidans’, followed by EAE to obtain a fraction defined as ‘interconnected fucoidans’. The process was applied to <em>Alaria esculenta</em> (AE) and <em>Saccharina latissima</em> (SL). Compositional and structural analyses by CHNS-analysis, HPAEC-PAD, SEC-MALS, and NMR revealed distinct differences between the two fucoidan fractions, including variations in monosaccharide composition, sulfation, and acetylation degrees. These differences, along with the varying extraction conditions required, suggest that the fractions represent distinct fucoidan types. We hypothesize that the chemically extracted fucoidans are not covalently bound to any structures and originate from the thallus surface or outer cell wall layers of the algae, while the EAE extracted fucoidans are more tightly bound (either covalently linked or entangled) to other cell wall components. Furthermore, a fraction of fucoidans from AE appeared to be covalently linked to polyphenols, as identified and characterized by NMR. To our knowledge, this is the first study describing potential covalent linkages between fucoidan and polyphenols in brown algae.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"93 ","pages":"Article 104450"},"PeriodicalIF":4.5,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-04DOI: 10.1016/j.algal.2025.104463
Enrica Giustino , Paola Imbimbo , Jenifer Trepiana , Maria P. Portillo , Daria Maria Monti
Lipid-related disorders, including lipid accumulation into adipose tissue, obesity, insulin resistance, as well as fatty liver disease share oxidative stress as one of the key pathways involved. Antioxidant molecules obtained from natural sources can be used to encounter consumers' concerns about chemically synthesized ones. It is well established that microalgae are a reliable source of a wide variety of environmentally friendly and safe antioxidant molecules. In particular, Porphyridium cruentum has been studied as an abundant source of phycoerythrin and sulfated exopolysaccharides, both endowed with a potent antioxidant activity. Here, for the first time, phycoerythrin and sulfated exopolysaccharides were explored for their ability to interfere with 3T3-L1 adipocytes differentiation, affect de novo lipogenesis and enhance lipolysis in mature adipocytes, as well as to counteract lipid storage in AML12 hepatocytes, used as a hepatic steatosis model. The isolated antioxidant molecules affected pre-adipocytes differentiation inhibiting the master regulator of adipogenesis and genes involved in adipocyte maturation. In the hepatic steatosis model, sulfated exopolysaccharides were able to inhibit de novo lipogenesis whereas phycoerythrin showed a pro-fat effect. This study highlights that counteracting the oxidative stress is a necessary although not sufficient condition to counteract all lipid-related disorders.
{"title":"A new application of phycoerythrin and sulfated exopolysaccharides from Porphyridium cruentum: Effects on the regulation of lipid metabolism","authors":"Enrica Giustino , Paola Imbimbo , Jenifer Trepiana , Maria P. Portillo , Daria Maria Monti","doi":"10.1016/j.algal.2025.104463","DOIUrl":"10.1016/j.algal.2025.104463","url":null,"abstract":"<div><div>Lipid-related disorders, including lipid accumulation into adipose tissue, obesity, insulin resistance, as well as fatty liver disease share oxidative stress as one of the key pathways involved. Antioxidant molecules obtained from natural sources can be used to encounter consumers' concerns about chemically synthesized ones. It is well established that microalgae are a reliable source of a wide variety of environmentally friendly and safe antioxidant molecules. In particular, <em>Porphyridium cruentum</em> has been studied as an abundant source of phycoerythrin and sulfated exopolysaccharides, both endowed with a potent antioxidant activity. Here, for the first time, phycoerythrin and sulfated exopolysaccharides were explored for their ability to interfere with 3T3-L1 adipocytes differentiation, affect <em>de novo</em> lipogenesis and enhance lipolysis in mature adipocytes, as well as to counteract lipid storage in AML12 hepatocytes, used as a hepatic steatosis model. The isolated antioxidant molecules affected pre-adipocytes differentiation inhibiting the master regulator of adipogenesis and genes involved in adipocyte maturation. In the hepatic steatosis model, sulfated exopolysaccharides were able to inhibit <em>de novo</em> lipogenesis whereas phycoerythrin showed a pro-fat effect. This study highlights that counteracting the oxidative stress is a necessary although not sufficient condition to counteract all lipid-related disorders.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"93 ","pages":"Article 104463"},"PeriodicalIF":4.5,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Microalgae are gaining increasing interest as sustainable feedstocks for producing diverse high-value biomolecules. In this study, a green microalga identified through microscopic and molecular approaches as Tetradesmus sp. LT1 was characterized according to its nutritional requirements, in order to determine stress conditions that maximize carotenoid production. Among the standard culture media, BG-11 supported the highest growth and biomass productivity. Variations in its composition were achieved through nitrogen deprivation and sodium chloride (NaCl) addition. Maximum quantum yield of photosystem II (Fv/Fm), respiration (μmolO₂.mL−1 min−1), and chlorophyll a were monitored to evaluate the performance of the strain. A three-factor central composite design was further introduced to impose combined nutritional and salinity stress by varying the NaCl, nitrate, and phosphate concentrations. The results indicated that all three factors significantly influenced biomass (optimal value 5.8 g/L) and lipid content (59.1 % under nitrate starvation and phosphate limitation and 47 g/L NaCl). For secondary carotenoids profiled by HPLC-DAD, only NaCl significantly and qualitatively affected their composition, leading to proportional increases in astaxanthin (17 %) and canthaxanthin (20 %). In contrast, violaxanthin increased with decreasing NaCl concentration, reaching 29 %, whereas lutein, the predominant carotenoid under all conditions, remained relatively stable (30–42 %). Overall, these results highlight the potential of Tetradesmus sp. LT1 as a valuable candidate for future biorefinery applications.
{"title":"Versatility of Tetradesmus sp. metabolism for multi-objective culture optimization: Assessment of metabolic state in response to combined nutritional and salt stress","authors":"Nadia Berrejeb , Cecilia Faraloni , Souhir Jazzar , Giuseppe Torzillo , Issam Smaali","doi":"10.1016/j.algal.2025.104465","DOIUrl":"10.1016/j.algal.2025.104465","url":null,"abstract":"<div><div>Microalgae are gaining increasing interest as sustainable feedstocks for producing diverse high-value biomolecules. In this study, a green microalga identified through microscopic and molecular approaches as <em>Tetradesmus</em> sp. LT1 was characterized according to its nutritional requirements, in order to determine stress conditions that maximize carotenoid production. Among the standard culture media, BG-11 supported the highest growth and biomass productivity. Variations in its composition were achieved through nitrogen deprivation and sodium chloride (NaCl) addition. Maximum quantum yield of photosystem II (Fv/Fm), respiration (μmolO₂.mL<sup>−1</sup> min<sup>−1</sup>), and chlorophyll <em>a</em> were monitored to evaluate the performance of the strain. A three-factor central composite design was further introduced to impose combined nutritional and salinity stress by varying the NaCl, nitrate, and phosphate concentrations. The results indicated that all three factors significantly influenced biomass (optimal value 5.8 g/L) and lipid content (59.1 % under nitrate starvation and phosphate limitation and 47 g/L NaCl). For secondary carotenoids profiled by HPLC-DAD, only NaCl significantly and qualitatively affected their composition, leading to proportional increases in astaxanthin (17 %) and canthaxanthin (20 %). In contrast, violaxanthin increased with decreasing NaCl concentration, reaching 29 %, whereas lutein, the predominant carotenoid under all conditions, remained relatively stable (30–42 %). Overall, these results highlight the potential of <em>Tetradesmus</em> sp. LT1 as a valuable candidate for future biorefinery applications.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"93 ","pages":"Article 104465"},"PeriodicalIF":4.5,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-03DOI: 10.1016/j.algal.2025.104456
Yanlu Qiao , Shuo Wang , Lingzhe Wang , Shijie Li , Feng Wang , Bo Wang , Zhangxi Hu , Yuyang Liu
Algae-associated microbiome represents a specialized consortium shaped by specific algae via long-term domestication, fostering a close relationship with the host population. However, the ecological features and contributions of different algae-associated microbial groups through the growth process of a bloom-causing species remain under-researched. Herein, via 16S rDNA high-throughput sequencing, the diversity, assembly mechanism, microbial interaction and community function of algae-associated bacterial, archaeal and fungal consortia were investigated and compared across the growth cycle of the dinoflagellate Alexandrium pacificum cultured in the laboratory for years without antibiotic treatment. The three microbial communities exhibited significant temporal heterogeneity among growth stages, with both species abundance and composition dynamics. Determinacy-dominated assembly processes within all microbial taxa were observed along the algal growth curve. Compared to other microbial groups, bacteria were featured by a larger proportion of network nodes, higher species diversity, more complex community and greater functional versatility, indicating their pivotal role in maintaining community stability. Functionally, bacterial taxa possessed more diverse pathways of biogeochemical cycling than other microbial types, with Marinobacteraceae and Thalassospiraceae emerging as key drivers, revealing their central positions in cycling of matter. Specifically, carbon, nitrogen and phosphorus cycle pathways were more abundant in the earlier growth stage, while sulfur, iron and vitamin B12 cycle pathways were mainly enriched in the stationary and senescence stages. Among them, the pathways involved in the supply of sulfate and VB12 showed a significantly positive correlation with algal density, implying their important contributions to algae proliferation. Altogether, these findings unmask the profiles of community succession and functional change among different algae-associated microorganisms across the algal growth cycle, particularly highlighting the important roles of bacterial taxa in upholding community stability and mediating biogeochemical cycling. This work provides an evolving comprehension on algal-microbe interactions and advances the understanding on how phycospheric microbiota shapes HAB dynamics and fate.
{"title":"Algae-associated bacteria play crucial roles in maintaining community stability and mediating biogeochemical cycles across the growth cycle of the toxic dinoflagellate Alexandrium pacificum","authors":"Yanlu Qiao , Shuo Wang , Lingzhe Wang , Shijie Li , Feng Wang , Bo Wang , Zhangxi Hu , Yuyang Liu","doi":"10.1016/j.algal.2025.104456","DOIUrl":"10.1016/j.algal.2025.104456","url":null,"abstract":"<div><div>Algae-associated microbiome represents a specialized consortium shaped by specific algae via long-term domestication, fostering a close relationship with the host population. However, the ecological features and contributions of different algae-associated microbial groups through the growth process of a bloom-causing species remain under-researched. Herein, via 16S rDNA high-throughput sequencing, the diversity, assembly mechanism, microbial interaction and community function of algae-associated bacterial, archaeal and fungal consortia were investigated and compared across the growth cycle of the dinoflagellate <em>Alexandrium pacificum</em> cultured in the laboratory for years without antibiotic treatment. The three microbial communities exhibited significant temporal heterogeneity among growth stages, with both species abundance and composition dynamics. Determinacy-dominated assembly processes within all microbial taxa were observed along the algal growth curve. Compared to other microbial groups, bacteria were featured by a larger proportion of network nodes, higher species diversity, more complex community and greater functional versatility, indicating their pivotal role in maintaining community stability. Functionally, bacterial taxa possessed more diverse pathways of biogeochemical cycling than other microbial types, with Marinobacteraceae and Thalassospiraceae emerging as key drivers, revealing their central positions in cycling of matter. Specifically, carbon, nitrogen and phosphorus cycle pathways were more abundant in the earlier growth stage, while sulfur, iron and vitamin B<sub>12</sub> cycle pathways were mainly enriched in the stationary and senescence stages. Among them, the pathways involved in the supply of sulfate and VB<sub>12</sub> showed a significantly positive correlation with algal density, implying their important contributions to algae proliferation. Altogether, these findings unmask the profiles of community succession and functional change among different algae-associated microorganisms across the algal growth cycle, particularly highlighting the important roles of bacterial taxa in upholding community stability and mediating biogeochemical cycling. This work provides an evolving comprehension on algal-microbe interactions and advances the understanding on how phycospheric microbiota shapes HAB dynamics and fate.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"93 ","pages":"Article 104456"},"PeriodicalIF":4.5,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The current research mainly aimed to reveal the impact of cyanobacterial exopolysaccharide on survival of crop plants in soil with high salt and petroleum hydrocarbon contaminant. Initially, exopolysaccharides (EPS) were extracted and purified from backwater cyanobacteria and the EPS producing backwater cyanobacterium was characterized using 16S rRNA as Westiellopsis sp. KM1, PQ435491. Physical characterization of purified EPS was confirmed by UV–Vis spectrum, HPLC, FTIR, SEM, TEM, 1H and 13C NMR, TGA and zeta potential analysis. Optimization of EPS production using Response Surface Methodology revealed that the maximum yield of 972 mg/L was achieved at pH 6.5, after 20 days of incubation, with 8 g/L NaCl, at 27.5 °C temperature and in the presence of 1.25 % glucose. After using cold acetone to precipitate EPS, 435 ± 0.01 mg/mL of total carbohydrates and 18.5 ± 1.06 mg/mL of protein were measured. The EPS showed excellent water-absorbing capacity (WAC), emulsification, and flocculation properties, evidenced the use in agricultural applications. The results of pot experiment showed that Oryza sativa and Solanum lycopersicum amended with EPS increased the plant growth parameters, photosynthetic pigments, proline content and reduced oxidative stress, sodium, potassium uptake under salt stress compared with the control. According to the findings above, it is recommended that cyanobacterial exopolysaccharide could be an effective bio-formulator for health improvement of agricultural crop with salt stress and an eco-friendly alternative to synthetic emulsifiers and flocculants.
{"title":"Westiellopsis-derived exopolysaccharide: A novel approach to alleviation of salt stress in plants and environmental cleanup","authors":"Monica Durairaj , Ramesh Ponnusamy , Balasubramani Ravindran , Douglas J.H. Shyu , Kavitha Thangavel","doi":"10.1016/j.algal.2025.104458","DOIUrl":"10.1016/j.algal.2025.104458","url":null,"abstract":"<div><div>The current research mainly aimed to reveal the impact of cyanobacterial exopolysaccharide on survival of crop plants in soil with high salt and petroleum hydrocarbon contaminant. Initially, exopolysaccharides (EPS) were extracted and purified from backwater cyanobacteria and the EPS producing backwater cyanobacterium was characterized using 16S rRNA as <em>Westiellopsis</em> sp. KM1, PQ435491. Physical characterization of purified EPS was confirmed by UV–Vis spectrum, HPLC, FTIR, SEM, TEM, <sup>1</sup>H and <sup>13</sup>C NMR, TGA and zeta potential analysis. Optimization of EPS production using Response Surface Methodology revealed that the maximum yield of 972 mg/L was achieved at pH 6.5, after 20 days of incubation, with 8 g/L NaCl, at 27.5 °C temperature and in the presence of 1.25 % glucose. After using cold acetone to precipitate EPS, 435 ± 0.01 mg/mL of total carbohydrates and 18.5 ± 1.06 mg/mL of protein were measured. The EPS showed excellent water-absorbing capacity (WAC), emulsification, and flocculation properties, evidenced the use in agricultural applications. The results of pot experiment showed that <em>Oryza sativa</em> and <em>Solanum lycopersicum</em> amended with EPS increased the plant growth parameters, photosynthetic pigments, proline content and reduced oxidative stress, sodium, potassium uptake under salt stress compared with the control. According to the findings above, it is recommended that cyanobacterial exopolysaccharide could be an effective bio-formulator for health improvement of agricultural crop with salt stress and an eco-friendly alternative to synthetic emulsifiers and flocculants.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"93 ","pages":"Article 104458"},"PeriodicalIF":4.5,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study introduces a decellularization-inspired strategy to isolate the tissue scaffold from the green macroalgae Ulva fenestrata as a platform for bio-based film production. A top-down approach was developed to remove cytosolic components while preserving the native hierarchical architecture. By combining chemical and mechanical treatments, it was shown that the addition of surfactant and mechanical treatment improved decellularization efficiency and scaffold integrity. The surfactant Cocamidopropyl betaine (CAPB) increased pigment extraction threefold during solvent treatment. Combined with ultrasonication, a synergistic effect enabled high extraction efficiency at solvent concentrations as low as 5–10 % and accelerated kinetics to equilibrium within 180 min. Auger-based mechanical pretreatment further enhanced extraction by promoting pigment removal before solvent-surfactant treatment.
Biopolymer anatomy mapping by optotracing with fluorescent reporter molecules showed tissue-dependent recovery: In blade tissue, thinner-walled regions were more affected, whereas thicker-walled tissues retained integrity through an intermediate lamella. In rhizoidal tissue, fibrils from the median layer were additionally isolated. In both tissues, impairment of the outermost layer enhanced decellularization efficiency. Carbotrace 680 stained blade cell walls, while rhizoidal cell walls required Carbotrace 630, highlighting compositional differences.
Fully algae-derived, self-standing films from decellularized Ulva were produced, reaching tensile strengths up to 39.7 MPa. Blade-derived films showed the highest performance, while rhizoidal films were more heterogeneous due to fibril inclusion. This demonstrates decellularization as a sustainable, low-input route to utilize macroalgal architectures for bio-based material development.
{"title":"From seaweed to scaffold: A top-down approach for liberating and utilizing the biopolymer tissue scaffold of Ulva fenestrata","authors":"Alina E.M. Schmidt , Sophie Steinhagen , Agneta Richter-Dahlfors , Ulrica Edlund","doi":"10.1016/j.algal.2025.104451","DOIUrl":"10.1016/j.algal.2025.104451","url":null,"abstract":"<div><div>This study introduces a decellularization-inspired strategy to isolate the tissue scaffold from the green macroalgae <em>Ulva fenestrata</em> as a platform for bio-based film production. A top-down approach was developed to remove cytosolic components while preserving the native hierarchical architecture. By combining chemical and mechanical treatments, it was shown that the addition of surfactant and mechanical treatment improved decellularization efficiency and scaffold integrity. The surfactant Cocamidopropyl betaine (CAPB) increased pigment extraction threefold during solvent treatment. Combined with ultrasonication, a synergistic effect enabled high extraction efficiency at solvent concentrations as low as 5–10 % and accelerated kinetics to equilibrium within 180 min. Auger-based mechanical pretreatment further enhanced extraction by promoting pigment removal before solvent-surfactant treatment.</div><div>Biopolymer anatomy mapping by optotracing with fluorescent reporter molecules showed tissue-dependent recovery: In blade tissue, thinner-walled regions were more affected, whereas thicker-walled tissues retained integrity through an intermediate lamella. In rhizoidal tissue, fibrils from the median layer were additionally isolated. In both tissues, impairment of the outermost layer enhanced decellularization efficiency. Carbotrace 680 stained blade cell walls, while rhizoidal cell walls required Carbotrace 630, highlighting compositional differences.</div><div>Fully algae-derived, self-standing films from decellularized <em>Ulva</em> were produced, reaching tensile strengths up to 39.7 MPa. Blade-derived films showed the highest performance, while rhizoidal films were more heterogeneous due to fibril inclusion. This demonstrates decellularization as a sustainable, low-input route to utilize macroalgal architectures for bio-based material development.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"93 ","pages":"Article 104451"},"PeriodicalIF":4.5,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-03DOI: 10.1016/j.algal.2025.104459
Ashley Ryland , Peter H. Chen , Mark Zivojnovich , Sungwhan Kim , Ryan W. Davis , Tyler Eckles , Jason C. Quinn , David Quiroz
Algal turf scrubbers (ATS) are a promising wastewater treatment technology that can simultaneously remove nutrients from effluent and generate algal biomass for conversion into renewable fuels. This study presents the first integrated techno-economic analysis (TEA) and life cycle assessment (LCA) of ATS systems treating effluent from point-source wastewater treatment plants across the continental United States. A regionally resolved process model was developed using watershed data to simulate nutrient removal and biomass production, with biomass subsequently routed to centralized biorefineries for conversion to renewable diesel via hydrothermal liquefaction. The analysis incorporates non-co-located infrastructure and average transportation distances to reflect real-word deployment logistics. Economic viability was evaluated using a discounted cash flow rate of return model, and environmental impacts were assessed using a well-to-wheels LCA framework. Moreover, the TEA incorporates differentiated nutrient credits for nitrogen and phosphorus removal, enabling a more accurate evaluation of water quality services. Results indicate that ATS systems are effective at nutrient removal, with 44 % of modeled sites achieving cost competitiveness for fuel production (< $0.87 per liter gasoline equivalent) when nutrient credits of $42 kg−1 for nitrogen or $321 kg−1 for phosphorus removal are applied. However, only 11 % of sites present lower life cycle greenhouse gas emissions below the renewable fuel standard (45 g CO2e MJ−1), posing a substantial constraint to widespread deployment. This highlights a critical challenge: most locations do not meet carbon intensity targets, limiting the viability of scaling up algal biofuel production in the US. Nonetheless, ATS systems exhibit lower energy and carbon intensity compared to conventional tertiary treatment technologies, offering a viable pathway toward integrated wastewater management and biomass production.
藻类草皮洗涤器（ATS）是一种很有前途的废水处理技术，它可以同时从废水中去除营养物质并产生藻类生物质转化为可再生燃料。本研究首次综合技术经济分析（TEA）和生命周期评估（LCA）的ATS系统处理污水从点源污水处理厂在美国大陆。研究人员利用流域数据建立了一个区域分解过程模型，模拟养分去除和生物质生产，然后将生物质输送到集中的生物精炼厂，通过水热液化转化为可再生柴油。该分析结合了非同一地点的基础设施和平均运输距离，以反映真实的部署物流。使用折现现金流回报率模型评估经济可行性，使用从油井到车轮的LCA框架评估环境影响。此外，TEA纳入了用于氮和磷去除的差异化营养信用，从而能够更准确地评估水质服务。结果表明，ATS系统在去除营养物方面是有效的，当氮的营养信用额为42 kg−1美元，磷的营养信用额为321 kg−1美元时，44%的模拟站点在燃料生产方面具有成本竞争力（每升汽油当量0.87美元）。然而，只有11%的站点的生命周期温室气体排放量低于可再生燃料标准（45 g CO2e MJ - 1），这对广泛部署构成了重大限制。这凸显了一个关键的挑战：大多数地区没有达到碳强度目标，限制了美国扩大藻类生物燃料生产的可行性。尽管如此，与传统的三级处理技术相比，ATS系统表现出更低的能源和碳强度，为综合废水管理和生物质生产提供了一条可行的途径。
{"title":"Techno-economic analysis and life cycle assessment of algal turf scrubbers treating wastewater effluent for renewable diesel production","authors":"Ashley Ryland , Peter H. Chen , Mark Zivojnovich , Sungwhan Kim , Ryan W. Davis , Tyler Eckles , Jason C. Quinn , David Quiroz","doi":"10.1016/j.algal.2025.104459","DOIUrl":"10.1016/j.algal.2025.104459","url":null,"abstract":"<div><div>Algal turf scrubbers (ATS) are a promising wastewater treatment technology that can simultaneously remove nutrients from effluent and generate algal biomass for conversion into renewable fuels. This study presents the first integrated techno-economic analysis (TEA) and life cycle assessment (LCA) of ATS systems treating effluent from point-source wastewater treatment plants across the continental United States. A regionally resolved process model was developed using watershed data to simulate nutrient removal and biomass production, with biomass subsequently routed to centralized biorefineries for conversion to renewable diesel <em>via</em> hydrothermal liquefaction. The analysis incorporates non-co-located infrastructure and average transportation distances to reflect real-word deployment logistics. Economic viability was evaluated using a discounted cash flow rate of return model, and environmental impacts were assessed using a well-to-wheels LCA framework. Moreover, the TEA incorporates differentiated nutrient credits for nitrogen and phosphorus removal, enabling a more accurate evaluation of water quality services. Results indicate that ATS systems are effective at nutrient removal, with 44 % of modeled sites achieving cost competitiveness for fuel production (< $0.87 per liter gasoline equivalent) when nutrient credits of $42 kg<sup>−1</sup> for nitrogen or $321 kg<sup>−1</sup> for phosphorus removal are applied. However, only 11 % of sites present lower life cycle greenhouse gas emissions below the renewable fuel standard (45 g CO<sub>2</sub>e MJ<sup>−1</sup>), posing a substantial constraint to widespread deployment. This highlights a critical challenge: most locations do not meet carbon intensity targets, limiting the viability of scaling up algal biofuel production in the US. Nonetheless, ATS systems exhibit lower energy and carbon intensity compared to conventional tertiary treatment technologies, offering a viable pathway toward integrated wastewater management and biomass production.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"93 ","pages":"Article 104459"},"PeriodicalIF":4.5,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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