Microalgae play a vital role in both environmental and industrial sectors. However, large-scale cultivation faces critical challenges, particularly microbial contamination, which drastically reduces biomass yield up to 70 %, often leading to sudden pond crashes. Preventing such biomass loss requires early and accurate identification of contaminants is crucial. Identification of contaminants based on microscopic and molecular methods remains labor-intensive, time-consuming, and require expertise in interpretation. To address these limitations, this study proposes a Deep Learning (DL)-based approach for automated classification of microalgae species using image data. A comprehensive dataset comprising 37 species, including green algae, diatoms, and dinoflagellates, was developed and 4 types of models (ResNet, MobileNet, DenseNet, EfficientNet) with a total of 12 variants were evaluated based on classification accuracy and F1-score. Among them, EfficientNet-B0 demonstrated the best performance, achieving an accuracy of 92.2 % while maintaining low computational overhead. The model uses AI to identify microalgae based on their shape and texture, enabling cost-effective and reliable monitoring.
{"title":"Image-based taxonomic classification of Microalgae using deep neural networks","authors":"Rajalakshmi Elumalai , Karthikeyan Meenatchi Sundaram , Selvaraj Barathi , Eswaran Kamaraj , Karthik Rajendran","doi":"10.1016/j.algal.2025.104486","DOIUrl":"10.1016/j.algal.2025.104486","url":null,"abstract":"<div><div>Microalgae play a vital role in both environmental and industrial sectors. However, large-scale cultivation faces critical challenges, particularly microbial contamination, which drastically reduces biomass yield up to 70 %, often leading to sudden pond crashes. Preventing such biomass loss requires early and accurate identification of contaminants is crucial. Identification of contaminants based on microscopic and molecular methods remains labor-intensive, time-consuming, and require expertise in interpretation. To address these limitations, this study proposes a Deep Learning (DL)-based approach for automated classification of microalgae species using image data. A comprehensive dataset comprising 37 species, including green algae, diatoms, and dinoflagellates, was developed and 4 types of models (ResNet, MobileNet, DenseNet, EfficientNet) with a total of 12 variants were evaluated based on classification accuracy and F1-score. Among them, EfficientNet-B0 demonstrated the best performance, achieving an accuracy of 92.2 % while maintaining low computational overhead. The model uses AI to identify microalgae based on their shape and texture, enabling cost-effective and reliable monitoring.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"94 ","pages":"Article 104486"},"PeriodicalIF":4.5,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974304","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 : 2026-01-05DOI: 10.1016/j.algal.2026.104517
Enyuan Liang , Mengchao Liu , Ze Yang, Tingyu Chen, Ruyi Dou, Rongxiu Tian, Xiaonan Zang, Di Xu
The meiosis-specific protein Spo11 is evolved from the ancestral A subunit of archaeal Topo VI. Within Archeaplastida, land plants possess two meiotic Spo11 genes and a eukaryotic TopoVIA gene, but it has long been assumed that green and red algae lack Spo11–1. Recent genome projects in red algae including Chondrus crispus, Gracilariopsis chorda and several unicellular taxes have shown that these species often contain more than two Spo11 paralogs: Spo11–1, Spo11–2, and Spo11–3/TopoVIA. Here we cloned three Spo11 genes from the economically important agarophytic red seaweed Gracilariopsis lemaneiformis and designated them GlSpo11–1, GlSpo11–2 and GlSpo11–3 based on sequence alignments and conserved domain analyses. Yeast sporulation assays demonstrated that only GlSpo11–1 and GlSpo11–2 compensated the sporulation defect of the Spo11-deleted Saccharomyces cerevisiae mutant and their complimentary efficiencies did not differ significantly. Quantitative real-time PCR (qRT-PCR) analysis further showed that both genes were upregulated in mature tetrasporophytes relative to immature tissues. Together, these results indicate that GlSpo11–1 and GlSpo11–2 are meiosis specific and that their encoded proteins likely function equivalently, possibly as a heterodimer. In contrast, only GlSpo11–3 interacted with GlTopoVIB in yeast hybrid assays, confirming that GlSpo11–3 represents the eukaryotic TopoVIA subunit and is not involved in meiosis. To the best of our knowledge, this study provides the first functional characterization of three Spo11 paralogs in red algae and suggests that Spo11–1 and Spo11–2 share equal importance in meiosis, consistent with their roles in land plants.
{"title":"Identification and functional analysis of meiotic Spo11 gene homologs in the red alga Gracilariopsis lemaneiformis (Rhodophyta, Gracilariales)","authors":"Enyuan Liang , Mengchao Liu , Ze Yang, Tingyu Chen, Ruyi Dou, Rongxiu Tian, Xiaonan Zang, Di Xu","doi":"10.1016/j.algal.2026.104517","DOIUrl":"10.1016/j.algal.2026.104517","url":null,"abstract":"<div><div>The meiosis-specific protein Spo11 is evolved from the ancestral A subunit of archaeal Topo VI. Within Archeaplastida, land plants possess two meiotic <em>Spo11</em> genes and a eukaryotic <em>TopoVIA</em> gene, but it has long been assumed that green and red algae lack <em>Spo11–1</em>. Recent genome projects in red algae including <em>Chondrus crispus, Gracilariopsis chorda</em> and several unicellular taxes have shown that these species often contain more than two Spo11 paralogs: Spo11–1, Spo11–2, and Spo11–3/TopoVIA. Here we cloned three <em>Spo11</em> genes from the economically important agarophytic red seaweed <em>Gracilariopsis lemaneiformis</em> and designated them <em>GlSpo11–1, GlSpo11–2</em> and <em>GlSpo11–3</em> based on sequence alignments and conserved domain analyses. Yeast sporulation assays demonstrated that only <em>GlSpo11–1</em> and <em>GlSpo11–2</em> compensated the sporulation defect of the <em>Spo11</em>-deleted <em>Saccharomyces cerevisiae</em> mutant and their complimentary efficiencies did not differ significantly. Quantitative real-time PCR (qRT-PCR) analysis further showed that both genes were upregulated in mature tetrasporophytes relative to immature tissues. Together, these results indicate that <em>GlSpo11–1</em> and <em>GlSpo11–2</em> are meiosis specific and that their encoded proteins likely function equivalently, possibly as a heterodimer. In contrast, only GlSpo11–3 interacted with GlTopoVIB in yeast hybrid assays, confirming that GlSpo11–3 represents the eukaryotic TopoVIA subunit and is not involved in meiosis. To the best of our knowledge, this study provides the first functional characterization of three Spo11 paralogs in red algae and suggests that Spo11–1 and Spo11–2 share equal importance in meiosis, consistent with their roles in land plants.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"94 ","pages":"Article 104517"},"PeriodicalIF":4.5,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923307","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}
Bioprospecting of native microalgae provides novel biotechnological resources; however, cultivation strategies that balance growth and metabolite production remain insufficiently defined. A freshwater Chlorella sp. from a Tucumán reservoir (Argentina) was established as an unialgal culture and identified to genus level by transmission electron microscopy.
We assessed the combined influence of culture medium, spectral quality, and photoperiod on growth kinetics and biochemical composition using a two-part experimental design. Experiment 1 assessed spectral quality (white vs. blue LED) in two media (BBM, F/2G), whereas Experiment 2 evaluated photoperiod (12:12 vs. 16:8 h) in both media using white LED. Growth parameters (μ, Td), pigments (chlorophyll a, chlorophyll b, carotenoids), proteins, lipids, carbohydrates, and phenolic compounds were quantified. Cell disruption protocols were optimized for low-biomass samples, enabling complete biochemical profiling at microscale.
Blue light enhanced growth rate but reduced pigment accumulation, whereas white light favored chlorophylls and carotenoids. Phenolics were stimulated under blue light and BBM medium. Photoperiod modulated biochemical allocation: 12:12 favored pigments, proteins, and carbohydrates, while 16:8 promoted phenolics and lipids, consistent with ROS-linked stress responses. Population and biochemical variables were integrated through Principal Component Analysis (PCA) to identify the variables most strongly differentiating treatments.
Together, the results suggested a two-part conceptual cultivation approach in which an initial photoacclimatory phase could be followed by a stress-inducing regime to enhance bioactive metabolites for food, nutraceutical, and agricultural applications. This is the first evaluation of cultivation strategies for freshwater chlorophytes from northwestern Argentina.
原生微藻的生物勘探提供了新的生物技术资源然而，平衡生长和代谢物产生的培养策略仍然不够明确。阿根廷Tucumán水库淡水小球藻（Chlorella sps .）为单藻培养体，经透射电镜鉴定为属水平。我们采用两部分实验设计评估了培养基、光谱质量和光周期对生长动力学和生化组成的综合影响。实验1评估了两种介质（BBM、F/2G）下的光谱质量（白光LED vs蓝光LED），而实验2评估了两种介质下使用白光LED的光周期（12:12 vs 16:8 h）。测定生长参数（μ, Td）、色素（叶绿素a、叶绿素b、类胡萝卜素）、蛋白质、脂类、碳水化合物和酚类化合物。针对低生物量样品，优化了细胞破坏方案，实现了微尺度下的完整生化分析。蓝光促进了生长速度，但减少了色素积累，而白光有利于叶绿素和类胡萝卜素的生长。在蓝光和BBM介质下刺激酚类物质。光周期调节生物化学分配：12:12有利于色素、蛋白质和碳水化合物，16:8促进酚类物质和脂类，与ros相关的应激反应一致。通过主成分分析（PCA）对种群变量和生化变量进行综合分析，找出对不同处理差异最大的变量。综上所述，研究结果建议采用两部分的概念性培养方法，即在初始光适应阶段之后进行应激诱导，以提高食品、营养和农业应用的生物活性代谢物。这是对阿根廷西北部淡水绿藻栽培策略的首次评价。
{"title":"Bioprospecting of a native Chlorella sp.: Culture strategies under contrasting light regimes reveal metabolic trade-offs between primary metabolism and phenolic accumulation","authors":"M.L. Iriarte , C.H. Armando , T.A. Rearte , J.R. Soberón , D.A. Sampietro , M.A. Sgariglia","doi":"10.1016/j.algal.2026.104518","DOIUrl":"10.1016/j.algal.2026.104518","url":null,"abstract":"<div><div>Bioprospecting of native microalgae provides novel biotechnological resources; however, cultivation strategies that balance growth and metabolite production remain insufficiently defined. A freshwater <em>Chlorella</em> sp. from a Tucumán reservoir (Argentina) was established as an unialgal culture and identified to genus level by transmission electron microscopy.</div><div>We assessed the combined influence of culture medium, spectral quality, and photoperiod on growth kinetics and biochemical composition using a two-part experimental design. Experiment 1 assessed spectral quality (white vs. blue LED) in two media (BBM, F/2G), whereas Experiment 2 evaluated photoperiod (12:12 vs. 16:8 h) in both media using white LED. Growth parameters (μ, Td), pigments (chlorophyll <em>a</em>, chlorophyll <em>b</em>, carotenoids), proteins, lipids, carbohydrates, and phenolic compounds were quantified. Cell disruption protocols were optimized for low-biomass samples, enabling complete biochemical profiling at microscale.</div><div>Blue light enhanced growth rate but reduced pigment accumulation, whereas white light favored chlorophylls and carotenoids. Phenolics were stimulated under blue light and BBM medium. Photoperiod modulated biochemical allocation: 12:12 favored pigments, proteins, and carbohydrates, while 16:8 promoted phenolics and lipids, consistent with ROS-linked stress responses. Population and biochemical variables were integrated through Principal Component Analysis (PCA) to identify the variables most strongly differentiating treatments.</div><div>Together, the results suggested a two-part conceptual cultivation approach in which an initial photoacclimatory phase could be followed by a stress-inducing regime to enhance bioactive metabolites for food, nutraceutical, and agricultural applications. This is the first evaluation of cultivation strategies for freshwater chlorophytes from northwestern Argentina.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"94 ","pages":"Article 104518"},"PeriodicalIF":4.5,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923346","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 : 2026-01-04DOI: 10.1016/j.algal.2025.104500
M.A. González-Cardoso , R. Yepez , E. Navarro-López , A. Contreras-Gómez , F.J. Alarcón-López , M.C. Cerón-García
Microalgae are considered a promising raw material for a variety of applications thanks to their nutritional profile. However, the rigid cell walls of certain species require pretreatments to facilitate the release of bioactive compounds. This study evaluated the impact of different pretreatments, including high-pressure homogenization (HPH), milling with alumina (M-AL), ultrasound (US), and microwave (MW), on protein hydrolysis and the recovery of fatty acids and carotenoids from the biomass of Nannochloropsis gaditana, Isochrysis galbana and Arthrospira platensis. All pretreatments significantly influenced protein hydrolysis. US at 80 % intensity resulted in the highest degree of hydrolysis (DH) for I. galbana (77 %), followed by N. gaditana (62 %). However, A. platensis showed no improvement compared to the control. Carotenoid recovery varied among species: the highest yield was achieved by N. gaditana (195 %) with US at 80 %, followed by I. galbana (180 %) with MW at 360 W, while the lowest recovery was observed in A. platensis (133 %) with HPH at 800 bar. Fatty acid yields also increased, with N. gaditana reaching 113 % (HPH at 800 bar) and 116 % (US at 80 %), and I. galbana reaching 112 % and 124 % under the same conditions. The highest recoveries in A. platensis were obtained with HPH at 400 and 800 bar (139 % and 135 %, respectively), compared to the untreated control. The bioactivity of the hydrolysates was assessed through the germination index of garden cress seeds. Only I. galbana hydrolysates enhanced germination, suggesting that specific pretreatments can improve the recovery of functional compounds from microalgae.
{"title":"Evaluation of pretreatments used to obtain hydrolysates from microalgae biomass, and their effects on the recovery of carotenoids and fatty acids intended for agriculture applications","authors":"M.A. González-Cardoso , R. Yepez , E. Navarro-López , A. Contreras-Gómez , F.J. Alarcón-López , M.C. Cerón-García","doi":"10.1016/j.algal.2025.104500","DOIUrl":"10.1016/j.algal.2025.104500","url":null,"abstract":"<div><div>Microalgae are considered a promising raw material for a variety of applications thanks to their nutritional profile. However, the rigid cell walls of certain species require pretreatments to facilitate the release of bioactive compounds. This study evaluated the impact of different pretreatments, including high-pressure homogenization (HPH), milling with alumina (M-AL), ultrasound (US), and microwave (MW), on protein hydrolysis and the recovery of fatty acids and carotenoids from the biomass of <em>Nannochloropsis gaditana</em>, <em>Isochrysis galbana</em> and <em>Arthrospira platensis</em>. All pretreatments significantly influenced protein hydrolysis. US at 80 % intensity resulted in the highest degree of hydrolysis (DH) for <em>I. galbana</em> (77 %), followed by <em>N. gaditana</em> (62 %). However, <em>A. platensis</em> showed no improvement compared to the control. Carotenoid recovery varied among species: the highest yield was achieved by <em>N. gaditana</em> (195 %) with US at 80 %, followed by <em>I. galbana</em> (180 %) with MW at 360 W, while the lowest recovery was observed in <em>A. platensis</em> (133 %) with HPH at 800 bar. Fatty acid yields also increased, with <em>N. gaditana</em> reaching 113 % (HPH at 800 bar) and 116 % (US at 80 %), and <em>I. galbana</em> reaching 112 % and 124 % under the same conditions. The highest recoveries in <em>A. platensis</em> were obtained with HPH at 400 and 800 bar (139 % and 135 %, respectively), compared to the untreated control. The bioactivity of the hydrolysates was assessed through the germination index of garden cress seeds. Only <em>I. galbana</em> hydrolysates enhanced germination, suggesting that specific pretreatments can improve the recovery of functional compounds from microalgae.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"94 ","pages":"Article 104500"},"PeriodicalIF":4.5,"publicationDate":"2026-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923280","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 constantly growing scientific knowledge has made sustainability and renewability as major issues of focus for environmental awareness and search for alternate environmentally conscious and cost-effective solutions. In recent years, algae have emerged as pragmatic bioresources and captivating area of research around the globe for exploring novel and high value compounds such as pigments, polysaccharides, lipids, fatty acids and proteins with potential applications in different industries. These compounds possess an array of bioactivities such as antimicrobial, antioxidant, anti-tumor and anti-inflammatory further finding wider applications in nutraceuticals, cosmeceuticals, pharmaceuticals and food industry. The review explores high value compounds obtained from algae, their extraction techniques and incorporation in diet for managing chronic diseases. Algal polysaccharides and polyphenols are also receiving interest in cosmoceutics for their skin protecting properties. Algae serve as an important and sustainable resource for vaccine delivery in aquaculture and wastewater treatment, as biofertilizers as well as for production of the bioplastics highlighting their role in circular bio-economy. Algal extracts and their biomolecules are gaining increasing commercial importance. Further emphasis in the present review has been placed on the market opportunities, commercialization of algae derived products, technical concerns and regulatory considerations. Algae offer a scalable and sustainable solution by bridging a gap between the biotechnology and green chemistry to meet the global demands for natural compounds. Thus, in recent times the biotechnological potential of the algae and their value-added molecules have increased and hence has become an important tool for agricultural, environmental and industrial sustainability. Continued research efforts will help in exploring the full potential of algae for future bio-industries.
{"title":"Algae and their value-added compounds: Commercialization and biotechnological application for future sustainability","authors":"Divjot Kour , Esha Goyal , Nitika Bhardwaj , Sofia Sharief Khan , Nirmal Renuka , Babita Sharma , Tanvir Kaur , Arshdeep Singh , Harpreet Kour , Ajar Nath Yadav , Amrik Singh Ahluwalia","doi":"10.1016/j.algal.2025.104499","DOIUrl":"10.1016/j.algal.2025.104499","url":null,"abstract":"<div><div>The constantly growing scientific knowledge has made sustainability and renewability as major issues of focus for environmental awareness and search for alternate environmentally conscious and cost-effective solutions. In recent years, algae have emerged as pragmatic bioresources and captivating area of research around the globe for exploring novel and high value compounds such as pigments, polysaccharides, lipids, fatty acids and proteins with potential applications in different industries. These compounds possess an array of bioactivities such as antimicrobial, antioxidant, anti-tumor and anti-inflammatory further finding wider applications in nutraceuticals, cosmeceuticals, pharmaceuticals and food industry. The review explores high value compounds obtained from algae, their extraction techniques and incorporation in diet for managing chronic diseases. Algal polysaccharides and polyphenols are also receiving interest in cosmoceutics for their skin protecting properties. Algae serve as an important and sustainable resource for vaccine delivery in aquaculture and wastewater treatment, as biofertilizers as well as for production of the bioplastics highlighting their role in circular bio-economy. Algal extracts and their biomolecules are gaining increasing commercial importance. Further emphasis in the present review has been placed on the market opportunities, commercialization of algae derived products, technical concerns and regulatory considerations. Algae offer a scalable and sustainable solution by bridging a gap between the biotechnology and green chemistry to meet the global demands for natural compounds. Thus, in recent times the biotechnological potential of the algae and their value-added molecules have increased and hence has become an important tool for agricultural, environmental and industrial sustainability. Continued research efforts will help in exploring the full potential of algae for future bio-industries.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"93 ","pages":"Article 104499"},"PeriodicalIF":4.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880330","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 : 2026-01-01DOI: 10.1016/j.algal.2025.104489
Tahir Burak Binkanat, Altan Ozkan
Spirulina is cultivated industrially for food supplement applications due to its high protein content and protein quality. This study assessed the influence of cultivation temperature on the productivity of widely accessible, protein-rich Spirulina strains under standardized bubble column photobioreactor conditions, with the goal of identifying strains with consistently high nutritional value across varying temperatures and culture age for outdoor applications. Five strains were first screened for protein content at 30 °C, and three with protein contents ≥60 % dry biomass were selected for cultivation at 25 °C, 35 °C, and 40 °C. Protein content was measured daily to determine variations, and protein quality was assessed at log and stationary growth phases. The metal content was analyzed to assess the toxic heavy metal bioaccumulation potential.
At the optimum temperature of 35 °C, the strains had similar biomass productivities. However, the protein contents were highly temperature and strain-specific. Based on the strain, under identical process conditions, a relatively stable protein content of around 65 % or a content variation from 30 to 70 % was observed through the cultivation. Growth at 25 °C lowered the biomass productivity without affecting the protein contents, and growth at 40 °C lowered both parameters. S. platensis UTEX 2340 had consistently the highest protein quality, reflected by its higher cumulative essential amino acid contents and essential amino acid index scores. However, at 35 °C, the strain also had a mercury content exceeding the safety limits set for food supplements. These findings demonstrate the importance of strain selection and cultivation temperature in maintaining the nutritional value of Spirulina-based products.
{"title":"Effects of cultivation temperature on protein production of selected Spirulina strains under photobioreactor conditions","authors":"Tahir Burak Binkanat, Altan Ozkan","doi":"10.1016/j.algal.2025.104489","DOIUrl":"10.1016/j.algal.2025.104489","url":null,"abstract":"<div><div><em>Spirulina</em> is cultivated industrially for food supplement applications due to its high protein content and protein quality. This study assessed the influence of cultivation temperature on the productivity of widely accessible, protein-rich <em>Spirulina</em> strains under standardized bubble column photobioreactor conditions, with the goal of identifying strains with consistently high nutritional value across varying temperatures and culture age for outdoor applications. Five strains were first screened for protein content at 30 °C, and three with protein contents ≥60 % dry biomass were selected for cultivation at 25 °C, 35 °C, and 40 °C. Protein content was measured daily to determine variations, and protein quality was assessed at log and stationary growth phases. The metal content was analyzed to assess the toxic heavy metal bioaccumulation potential.</div><div>At the optimum temperature of 35 °C, the strains had similar biomass productivities. However, the protein contents were highly temperature and strain-specific. Based on the strain, under identical process conditions, a relatively stable protein content of around 65 % or a content variation from 30 to 70 % was observed through the cultivation. Growth at 25 °C lowered the biomass productivity without affecting the protein contents, and growth at 40 °C lowered both parameters. <em>S. platensis</em> UTEX 2340 had consistently the highest protein quality, reflected by its higher cumulative essential amino acid contents and essential amino acid index scores. However, at 35 °C, the strain also had a mercury content exceeding the safety limits set for food supplements. These findings demonstrate the importance of strain selection and cultivation temperature in maintaining the nutritional value of <em>Spirulina</em>-based products.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"93 ","pages":"Article 104489"},"PeriodicalIF":4.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145920654","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 : 2026-01-01DOI: 10.1016/j.algal.2025.104488
Karla Dussan , Paulina S. Birgersson , Stefania Luzzi , Olav A. Aarstad , Esther Cobussen-Pool , Tim Koster , Heather E. Wray , Finn L. Aachmann
Different routes for extraction of polysaccharides (fucoidan, alginate) and biomethane production were evaluated for the valorisation of Sargassum spp. biomass. Modest yields of alginate (145 g/kg dry biomass) and fucoidan (43 g/kg dry biomass) were achieved through sequential low temperature acidic aqueous treatment and alkaline extraction. The crude extracts showed low molecular weights (45.2 and 79.5 kDa, respectively) and had brown colour suggesting the presence of polyphenols. High temperature aqueous treatment increased fucoidan extraction efficiency, as indicated by higher fucose content in hydrolysates; however, the extract had low molecular weight (<10 kDa) leading to low crude fucoidan yield (27 g/kg dry biomass) and low fucose content. The alginate extraction yield and composition were negatively affected by the higher temperature treatment. Anaerobic digestion (AD) tests of untreated and treated fractions of Sargassum biomass showed that high temperature aqueous treatment can increase the biomethane production potential by up to 5 times (from 23.5 to 153.3 m3/ton volatile solids). The most energy-rich and AD suitable fraction from the high temperature aqueous treatment was the hydrolysate fraction, containing fucoidan and other solubilised organics, while the residual Sargassum biomass displayed relatively low biomethane potential (79.7 m3/ton volatile solids). A simplified economic analysis suggests that using Sargassum biomass in the Caribbean can be profitable (ROI between 12 and 28 %), and products such as fucoidan and alginate may enhance economic viability. However, the study shows the sensitivity of valorisation concepts to both product prices and yields, in particular the risk associated with poor product quality.
{"title":"Harnessing Sargassum inundation biomass: Biobased products versus energy valorisation","authors":"Karla Dussan , Paulina S. Birgersson , Stefania Luzzi , Olav A. Aarstad , Esther Cobussen-Pool , Tim Koster , Heather E. Wray , Finn L. Aachmann","doi":"10.1016/j.algal.2025.104488","DOIUrl":"10.1016/j.algal.2025.104488","url":null,"abstract":"<div><div>Different routes for extraction of polysaccharides (fucoidan, alginate) and biomethane production were evaluated for the valorisation of <em>Sargassum</em> spp. biomass. Modest yields of alginate (145 g/kg dry biomass) and fucoidan (43 g/kg dry biomass) were achieved through sequential low temperature acidic aqueous treatment and alkaline extraction. The crude extracts showed low molecular weights (45.2 and 79.5 kDa, respectively) and had brown colour suggesting the presence of polyphenols. High temperature aqueous treatment increased fucoidan extraction efficiency, as indicated by higher fucose content in hydrolysates; however, the extract had low molecular weight (<10 kDa) leading to low crude fucoidan yield (27 g/kg dry biomass) and low fucose content. The alginate extraction yield and composition were negatively affected by the higher temperature treatment. Anaerobic digestion (AD) tests of untreated and treated fractions of <em>Sargassum</em> biomass showed that high temperature aqueous treatment can increase the biomethane production potential by up to 5 times (from 23.5 to 153.3 m<sup>3</sup>/ton volatile solids). The most energy-rich and AD suitable fraction from the high temperature aqueous treatment was the hydrolysate fraction, containing fucoidan and other solubilised organics, while the residual <em>Sargassum</em> biomass displayed relatively low biomethane potential (79.7 m<sup>3</sup>/ton volatile solids). A simplified economic analysis suggests that using <em>Sargassum</em> biomass in the Caribbean can be profitable (ROI between 12 and 28 %), and products such as fucoidan and alginate may enhance economic viability. However, the study shows the sensitivity of valorisation concepts to both product prices and yields, in particular the risk associated with poor product quality.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"93 ","pages":"Article 104488"},"PeriodicalIF":4.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145920655","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 : 2026-01-01DOI: 10.1016/j.algal.2025.104491
Zirui Zhou , Duoduo Chen , Naif Abdullah Al-Dhabi , Caicheng Long , Taiping Qing , Bo Feng , Wangwang Tang , Peng Zhang
The utilization of algal-bacterial biomass for sustainable, low-carbon agricultural development represents a promising strategy for the efficient recycling of resources. This study explored the effect of cyanophycin granule polypeptide (CGP) extract on rice seed resistance and underlying mechanisms under various stress conditions. Results revealed that CGP notably improved the germination rate and growth of rice seeds subjected to drought (20 % polyethylene glycol), heavy metal contamination (3 mg/L Cd2+), and salinity (50 mM NaCl). After 48 h, seeds treated with 30 mg/L CGP exhibited a germination rate of 90 ± 2 %, significantly outperforming other treatments (P < 0.05). CGP treatment also elevated soluble sugar and protein levels, boosted α-amylase activity, and ensured adequate energy and nutrition for seed germination. Additionally, CGP enhanced seed antioxidant capacity, significantly increasing the activities of superoxide dismutase, peroxidase, and catalase, while reducing malondialdehyde content and mitigating membrane lipid peroxidation. CGP further promoted proline accumulation, improving the water retention capacity of rice seeds. Metabolomic analysis indicated that CGP induced metabolic reprogramming, driving the synthesis of stress-related metabolites such as phenolic compounds and salicylic acid, thus strengthening the seed's immune response. Notably, the ‘stress memory’ effects persisted into the seedling stage. This study introduces a novel approach for employing CGP as a plant biostimulant to enhance crop resilience under abiotic stress.
利用藻类-细菌生物量实现可持续的低碳农业发展是一种有效的资源循环利用策略。本研究探讨了不同胁迫条件下紫藻素颗粒多肽（CGP）提取物对水稻种子抗性的影响及其机制。结果表明，在干旱（20%聚乙二醇）、重金属污染（3 mg/L Cd2+）和盐度（50 mM NaCl）条件下，CGP显著提高了水稻种子的发芽率和生长。30 mg/L CGP处理48 h后，种子萌发率为90±2%，显著优于其他处理（P < 0.05）。CGP处理还提高了可溶性糖和蛋白质水平，提高了α-淀粉酶活性，确保了种子萌发所需的足够能量和营养。此外，CGP还能增强种子抗氧化能力，显著提高种子超氧化物歧化酶、过氧化物酶和过氧化氢酶的活性，降低丙二醛含量，减轻膜脂过氧化。CGP进一步促进了脯氨酸的积累，提高了水稻种子的保水性。代谢组学分析表明，CGP诱导代谢重编程，驱动应激相关代谢物如酚类化合物和水杨酸的合成，从而增强种子的免疫应答。值得注意的是，“胁迫记忆”效应持续到苗期。本研究介绍了一种利用CGP作为植物生物刺激素来提高作物在非生物胁迫下的抗逆性的新方法。
{"title":"Algal-bacterial consortia-derived cyanophycin reprograms rice seed metabolism for enhanced abiotic stress resilience","authors":"Zirui Zhou , Duoduo Chen , Naif Abdullah Al-Dhabi , Caicheng Long , Taiping Qing , Bo Feng , Wangwang Tang , Peng Zhang","doi":"10.1016/j.algal.2025.104491","DOIUrl":"10.1016/j.algal.2025.104491","url":null,"abstract":"<div><div>The utilization of algal-bacterial biomass for sustainable, low-carbon agricultural development represents a promising strategy for the efficient recycling of resources. This study explored the effect of cyanophycin granule polypeptide (CGP) extract on rice seed resistance and underlying mechanisms under various stress conditions. Results revealed that CGP notably improved the germination rate and growth of rice seeds subjected to drought (20 % polyethylene glycol), heavy metal contamination (3 mg/L Cd<sup>2+</sup>), and salinity (50 mM NaCl). After 48 h, seeds treated with 30 mg/L CGP exhibited a germination rate of 90 ± 2 %, significantly outperforming other treatments (<em>P</em> < 0.05). CGP treatment also elevated soluble sugar and protein levels, boosted α-amylase activity, and ensured adequate energy and nutrition for seed germination. Additionally, CGP enhanced seed antioxidant capacity, significantly increasing the activities of superoxide dismutase, peroxidase, and catalase, while reducing malondialdehyde content and mitigating membrane lipid peroxidation. CGP further promoted proline accumulation, improving the water retention capacity of rice seeds. Metabolomic analysis indicated that CGP induced metabolic reprogramming, driving the synthesis of stress-related metabolites such as phenolic compounds and salicylic acid, thus strengthening the seed's immune response. Notably, the ‘stress memory’ effects persisted into the seedling stage. This study introduces a novel approach for employing CGP as a plant biostimulant to enhance crop resilience under abiotic stress.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"93 ","pages":"Article 104491"},"PeriodicalIF":4.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880218","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 : 2026-01-01DOI: 10.1016/j.algal.2025.104508
Chunzhi Zhao , Rui Feng , Zhengfang Wang , Jing Wei , Yongjun Zhao , Shoubing Wang
Aquaculture wastewater frequently contains residual multi-class antibiotics and antibiotic resistance genes (ARGs), which pose severe ecological risks and remain challenging for traditional treatment technologies to address effectively. Phytohormones were selected as regulatory factors because of their well-documented role in modulating microbial growth, photosynthetic activity, and metabolic synergy—key traits for enhancing the pollutant removal capacity of symbiotic algal-bacterial-fungal systems. This study investigated the effects of four phytohormones, including gibberellic acid (GA3), indole-3-acetic acid (IAA), strigolactone analog GR24, and abscisic acid (ABA), on the removal of six target antibiotics and corresponding ARGs using four algal-bacterial-fungal symbiotic systems. The tested systems included the monoculture of Scenedesmus obliquus, algal-bacterial co-culture, algal-fungal co-culture, and algal-bacterial-fungal tri-culture of S. obliquus-Pseudomonas sp.-Aspergillus niger. Results showed that the tri-culture system treated with 50 mg L−1 GA3 achieved the highest removal efficiency for all pollutants. For antibiotics, tetracyclines (TET) including Tetracycline (TET) and Chlortetracycline (CTC) had the highest removal rates at 99.81 % and 97.34 %, followed by quinolones (QNs) including Ciprofloxacin (CIP) and Enrofloxacin (ENR) at 81.36 % and 78.52 %, and sulfonamides (SAs) including Sulfadiazine (SDZ) and Sulfamethoxazole (SMX) at 71.81 % and 68.53 %. For ARGs, plasmid-borne genes sul1 and sul2 exhibited the most significant reduction (3.67 lg copies and 2.87 lg copies, respectively), while tetracycline resistance genes (tetA, tetB) and quinolone resistance genes (qnrA, gyrA) showed relatively smaller reductions (2.51, 1.41 lg copies and 1.16, 1.31 lg copies, respectively). Mechanistically, GA3 enhanced the tri-culture's performance by improving photosynthetic efficiency. This improvement was reflected in increased maximum photochemical efficiency of PSII (FV/FM = 0.89) and photosynthetic performance index (PIABS = 7.51). This study demonstrated that the GA3-regulated S. obliquus-Pseudomonas sp.-Aspergillus niger tri-culture system offers a novel and sustainable strategy for aquaculture wastewater treatment.
{"title":"Phytohormone-regulated algal-bacterial-fungal tri-culture for efficient removal of antibiotics and antibiotic resistance genes in wastewater","authors":"Chunzhi Zhao , Rui Feng , Zhengfang Wang , Jing Wei , Yongjun Zhao , Shoubing Wang","doi":"10.1016/j.algal.2025.104508","DOIUrl":"10.1016/j.algal.2025.104508","url":null,"abstract":"<div><div>Aquaculture wastewater frequently contains residual multi-class antibiotics and antibiotic resistance genes (ARGs), which pose severe ecological risks and remain challenging for traditional treatment technologies to address effectively. Phytohormones were selected as regulatory factors because of their well-documented role in modulating microbial growth, photosynthetic activity, and metabolic synergy—key traits for enhancing the pollutant removal capacity of symbiotic algal-bacterial-fungal systems. This study investigated the effects of four phytohormones, including gibberellic acid (GA3), indole-3-acetic acid (IAA), strigolactone analog GR24, and abscisic acid (ABA), on the removal of six target antibiotics and corresponding ARGs using four algal-bacterial-fungal symbiotic systems. The tested systems included the monoculture of <em>Scenedesmus obliquus</em>, algal-bacterial co-culture, algal-fungal co-culture, and algal-bacterial-fungal tri-culture of <em>S. obliquus</em>-<em>Pseudomonas</em> sp.-<em>Aspergillus niger</em>. Results showed that the tri-culture system treated with 50 mg L<sup>−1</sup> GA3 achieved the highest removal efficiency for all pollutants. For antibiotics, tetracyclines (TET) including Tetracycline (TET) and Chlortetracycline (CTC) had the highest removal rates at 99.81 % and 97.34 %, followed by quinolones (QNs) including Ciprofloxacin (CIP) and Enrofloxacin (ENR) at 81.36 % and 78.52 %, and sulfonamides (SAs) including Sulfadiazine (SDZ) and Sulfamethoxazole (SMX) at 71.81 % and 68.53 %. For ARGs, plasmid-borne genes <em>sul</em>1 and <em>sul</em>2 exhibited the most significant reduction (3.67 lg copies and 2.87 lg copies, respectively), while tetracycline resistance genes (<em>tet</em>A, <em>tet</em>B) and quinolone resistance genes (<em>qnr</em>A, <em>gyr</em>A) showed relatively smaller reductions (2.51, 1.41 lg copies and 1.16, 1.31 lg copies, respectively). Mechanistically, GA3 enhanced the tri-culture's performance by improving photosynthetic efficiency. This improvement was reflected in increased maximum photochemical efficiency of PSII (<em>F</em><sub>V</sub>/<em>F</em><sub>M</sub> = 0.89) and photosynthetic performance index (<em>PI</em><sub>ABS</sub> = 7.51). This study demonstrated that the GA3-regulated <em>S. obliquus</em>-<em>Pseudomonas</em> sp.-<em>Aspergillus niger</em> tri-culture system offers a novel and sustainable strategy for aquaculture wastewater treatment.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"93 ","pages":"Article 104508"},"PeriodicalIF":4.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880220","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 : 2026-01-01DOI: 10.1016/j.algal.2025.104494
Andres Niroda , Rando Tuvikene , Michael Landreh , Mihkel Saluri
R-phycoerythrin (R-PE) is a vivid, proteinaceous pigment found in nature that holds promise for applications in biotechnology, cosmetics, and the food industry. Because recombinant production of the intact α-, β-, and γ-subunit R-PE complex remains challenging, it is purified from naturally sourced red algae. Notably, R-PE properties vary among algal species, offering opportunities to select optimal sources for specific applications. Here, we purified R-PE from ten red algal species and characterised them using a multi-dimensional strategy integrating UV–Vis absorption spectroscopy, fluorimetry, HPLC, and native mass spectrometry to pinpoint interspecies differences.
In a comparative analysis of ten red algae species, R-PE from Ceramium tenuicorne displayed the highest fluorescence intensity, likely due to a protein environment that maintains chromophores in an elongated conformation, promoting efficient energy transfer. Measurements also showed that Furcellaria lumbricalis and Rhodomela confervoides isolates exhibited 4–5-times lower fluorescence intensity at similar absorbances, suggesting they are more suitable for food colouring than as fluorescent probes. Using RP-HPLC with a PDA detector, a blue-shift in the α-subunit absorbance was observed for F. lumbricalis and the presence of two α-subunit isoforms in Neopyropia yezoensis were identified, indicating greater interspecies heterogeneity than previously recognised. In contrast, absorbances of β- and γ-subunits displayed remarkable consistency. Fluorescence intensity of intact R-PE was positively associated with γ-subunit hydrophilicity and absorbance, underscoring the crucial role of the central γ-subunits in R-PE brightness.
r -藻红蛋白（R-PE）是一种在自然界中发现的生动的蛋白质色素，在生物技术、化妆品和食品工业中有着广阔的应用前景。由于完整的α-、β-和γ-亚基R-PE复合物的重组生产仍然具有挑战性，因此从天然来源的红藻中纯化。值得注意的是，R-PE的性质因藻类种类而异，为特定应用选择最佳来源提供了机会。在这里，我们从10种红藻中纯化了R-PE，并使用UV-Vis吸收光谱、荧光法、HPLC和原生质谱法等多维策略对它们进行了表征，以确定种间差异。在对10种红藻的比较分析中，来自tenuicorne的R-PE显示出最高的荧光强度，这可能是由于蛋白质环境使发色团保持长形构象，促进有效的能量转移。测量还表明，在相似的吸光度下，腰状镰刀菌和凹形Rhodomela分离株的荧光强度低4 - 5倍，表明它们更适合用于食品着色而不是作为荧光探针。采用带PDA检测器的反相高效液相色谱（RP-HPLC）技术，观察到黄螺旋藻(F. lumbricalis) α-亚基吸光度发生蓝移，并在Neopyropia yezoensis中鉴定出两种α-亚基异构体，表明其种间异质性比之前认识到的更大。相比之下，β-和γ-亚基的吸光度具有显著的一致性。完整R-PE的荧光强度与γ-亚基的亲水性和吸光度呈正相关，强调了中心γ-亚基在R-PE亮度中的关键作用。
{"title":"Unravelling the hidden complexities of R-phycoerythrins with a 3D-analytical chemistry approach","authors":"Andres Niroda , Rando Tuvikene , Michael Landreh , Mihkel Saluri","doi":"10.1016/j.algal.2025.104494","DOIUrl":"10.1016/j.algal.2025.104494","url":null,"abstract":"<div><div>R-phycoerythrin (R-PE) is a vivid, proteinaceous pigment found in nature that holds promise for applications in biotechnology, cosmetics, and the food industry. Because recombinant production of the intact α-, β-, and γ-subunit R-PE complex remains challenging, it is purified from naturally sourced red algae. Notably, R-PE properties vary among algal species, offering opportunities to select optimal sources for specific applications. Here, we purified R-PE from ten red algal species and characterised them using a multi-dimensional strategy integrating UV–Vis absorption spectroscopy, fluorimetry, HPLC, and native mass spectrometry to pinpoint interspecies differences.</div><div>In a comparative analysis of ten red algae species, R-PE from <em>Ceramium tenuicorne</em> displayed the highest fluorescence intensity, likely due to a protein environment that maintains chromophores in an elongated conformation, promoting efficient energy transfer. Measurements also showed that <em>Furcellaria lumbricalis</em> and <em>Rhodomela confervoides</em> isolates exhibited 4–5-times lower fluorescence intensity at similar absorbances, suggesting they are more suitable for food colouring than as fluorescent probes. Using RP-HPLC with a PDA detector, a blue-shift in the α-subunit absorbance was observed for <em>F. lumbricalis</em> and the presence of two α-subunit isoforms in <em>Neopyropia yezoensis</em> were identified, indicating greater interspecies heterogeneity than previously recognised. In contrast, absorbances of β- and γ-subunits displayed remarkable consistency. Fluorescence intensity of intact R-PE was positively associated with γ-subunit hydrophilicity and absorbance, underscoring the crucial role of the central γ-subunits in R-PE brightness.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"93 ","pages":"Article 104494"},"PeriodicalIF":4.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145920656","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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