Algal Research-Biomass Biofuels and Bioproducts最新文献

{"title":"Nutrient deprivation stimulates soluble extracellular polymeric substances: physiological and biochemical responses in the cyanobacterium Cyanocohniella rudolphia","authors":"Filipa Rodrigues ,&nbsp;Ivana Mendonça ,&nbsp;Marisa Faria ,&nbsp;Karine Mougin ,&nbsp;Juan Luis Gómez Pinchetti ,&nbsp;Artur Ferreira ,&nbsp;Nereida Cordeiro","doi":"10.1016/j.algal.2026.104600","DOIUrl":"10.1016/j.algal.2026.104600","url":null,"abstract":"<div><div>The effect of macro- and micronutrient deprivation on the cyanobacterium <em>Cyanocohniella rudolphia</em> (BEA 0786B) over 180 days (without medium renewal) was evaluated to intensify the production of soluble extracellular polymeric substances (S-EPS). Growth, pH, cell-free medium viscosity, S-EPS content (phenol‑sulfuric acid assay), Alcian Blue staining, and biochemical/structural markers were monitored to assess EPS release and extracellular matrix dynamics. Progressive nutrient depletion induced a shift from biomass growth toward extracellular-matrix investment. Microcolony formation observed around day 45 preceded a sustained high-production phase, with pronounced matrix densification evident by approximately day 75. Apparent viscosity increased in parallel with S-EPS accumulation and showed a strong correlation with extracellular carbohydrate concentration (R² = 0.86), supporting its use as an operational, non-destructive proxy for S-EPS. Alcian Blue staining qualitatively confirmed the presence of acidic polysaccharides. Quantitatively, S-EPS concentrations increased from 0.1 to 0.8 g L⁻¹, accompanied by an increase in apparent viscosity from 24.7 to 34.7 mPa·s. Morphological and spectroscopic analyses indicated a predominantly carbohydrate-rich extracellular matrix with an increasing protein contribution over time.</div><div>As an exploratory proof of concept, unprocessed S-EPS present in the spent culture medium enabled LAP-initiated photochemical formation of Au and Ag nanoparticles at 365 nm, with S-EPS acting as a stabilising and co-reducing matrix and conferring pH-responsive optical behaviour. This indicates a practical route toward integration into EPS-rich matrices to engineer stimuli-responsive coatings and biomaterials. Overall, this study demonstrates that prolonged nutrient deprivation without medium renewal is an effective strategy to intensify S-EPS accumulation in <em>C. rudolphia</em> and that apparent viscosity provides a practical in-process parameter for monitoring production and supporting direct valorisation of spent culture medium in saline bioprocesses.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"95 ","pages":"Article 104600"},"PeriodicalIF":4.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147386400","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}

{"title":"Discovery and characterization of novel fucoidanases for depolymerization of Macrocystis pyrifera fucoidan","authors":"Diego S. Reyes-Weiss ,&nbsp;Alexander Mika Hannasvik ,&nbsp;Kristina H. Meszaros ,&nbsp;Victoria J. Demmene ,&nbsp;Gordon Jacob Boehlich ,&nbsp;Margot Bligh ,&nbsp;Manuel Liebeke ,&nbsp;Jan-Hendrik Hehemann ,&nbsp;Runar Stokke ,&nbsp;Bjørge Westereng ,&nbsp;Finn L. Aachmann ,&nbsp;Svein J. Horn ,&nbsp;Nanna Rhein-Knudsen","doi":"10.1016/j.algal.2026.104601","DOIUrl":"10.1016/j.algal.2026.104601","url":null,"abstract":"<div><div>Brown algae are central players in marine ecology and a rich, renewable resource with a millennia-long history of human use. Their extracellular matrix contains unique anionic polysaccharides, including fucoidans, recognized both as promising therapeutic agents and important players in biogeochemical carbon cycling. Fucoidans are structurally diverse and complex, and still not fully resolved at the molecular level, a challenge that has long hindered their systematic study and translation into biotechnological applications. This structural ambiguity has also contributed to inconsistent terminology within the field. Here, we outline the historical development of fucoidan structural characterization and nomenclature, identify recurring semantic inconsistencies, and propose a standardized terminology. Furthermore, we developed a mild extraction procedure that preserves native fucoidan structure and yields a high-molecular-weight, highly sulfated fucan from <em>Macrocystis pyrifera</em> biomass. Using this material as substrate for enzyme discovery enabled the identification of six novel fucoidanases, fucoidan-degrading enzymes, belonging to families GH107 and GH168. These enzymes originate from specialized fucoidan degrading genus <em>Lentimonas</em> spp. and a deep-sea hydrothermal vent metagenome. Comprehensive analytical characterization revealed distinct substrate specificities, reaction rates, and depolymerization mechanisms among these enzymes. The GH107 enzyme P5AFcnA exhibited the highest activity and was selected for detailed mechanistic and structural studies. Time-resolved analyses demonstrated that P5AFcnA depolymerizes <em>M. pyrifera</em> fucoidan through an endolytic mode of action, generating oligosaccharide intermediates that are further degraded into two sulfated tetramers bearing five and six sulfate esters, as well as a fucose-2,4-disulfate monomer. A recalcitrant fraction enriched in galactose remained undigested. Together, these findings highlight the importance of gentle extraction methods for preserving native fucoidan structure and thereby enabling enzyme characterization. Beyond expanding the enzymatic toolbox for fucoidan processing, this work provides a comprehensive structural analysis of <em>M. pyrifera</em> fucoidan and advances conceptual clarity in the field through a proposed standardized nomenclature system.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"95 ","pages":"Article 104601"},"PeriodicalIF":4.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147386480","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}

{"title":"Bead milling and ultrasonication as scalable techniques for cell disruption of Chlorella vulgaris","authors":"Tom Bernaerts,&nbsp;Sarah Goossens,&nbsp;Erwin Swinnen,&nbsp;Audrey De Cuyper,&nbsp;Floris Schoeters,&nbsp;Sabine Van Miert","doi":"10.1016/j.algal.2026.104613","DOIUrl":"10.1016/j.algal.2026.104613","url":null,"abstract":"<div><div>This study investigates the effectiveness of bead milling and ultrasonication for cell disruption and release of soluble compounds on <em>C. vulgaris</em> suspensions. Bead milling and ultrasonication were performed in semicontinuous mode, both on suspensions made from fresh algal paste and from lyophilized microalgae, to study the effect of starting material. Whereas bead milling resulted in complete cell disruption, ultrasonication only disrupted 74–84% of the <em>C. vulgaris</em> cells, as quantified by cell counting. For both treatments, cell disruption followed first order kinetics described by a fractional conversion model. No differences in disruption rate were observed between both techniques, only in the final degree of disruption. The release of soluble carbohydrates, proteins and pigments followed the same kinetics as for cell disruption. Even though preventive cooling measures were implemented, the occurrence of local high temperatures during ultrasonication led to protein aggregation and pigment degradation for treatment times longer than 45 min, while this was not observed for bead milling. Finally, the difference in starting material (fresh algal paste vs. resuspended lyophilized powder) only had a minor impact on the initial degree of disruption, but there was no significant effect on the final degree of disruption. While both bead milling and ultrasonication are scalable disruption techniques, bead milling is the most favorable technique for disruption of microalgal cells with a tougher cell wall like <em>C. vulgaris</em>, due to the higher effectiveness to achieve full cell disruption.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"95 ","pages":"Article 104613"},"PeriodicalIF":4.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147386481","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}

{"title":"Chemical characterization, phytochemical profiling, antioxidant and antidiabetic properties of Halopithys incurva (Hudson) Batters, 1902: In vitro and in silico approaches","authors":"Youssra Aalilou ,&nbsp;Güneş Ak ,&nbsp;Bouchra Rossafi ,&nbsp;Mustapha Hassoun ,&nbsp;Hanaa Moussa ,&nbsp;Gokhan Zengin ,&nbsp;Samir Chtita ,&nbsp;Mohammed Amanullah ,&nbsp;Abdelhakim Bouyahya ,&nbsp;My El Abbes Faouzi","doi":"10.1016/j.algal.2026.104603","DOIUrl":"10.1016/j.algal.2026.104603","url":null,"abstract":"<div><div>Postprandial hyperglycemia (PPHG) is an early disturbance in glucose homeostasis linked to type 2 diabetes (T2D) and is often accompanied by oxidative stress. Inhibiting carbohydrate-hydrolyzing enzymes, particularly α-amylase and α-glucosidase is a key strategy for managing PPHG and preventing T2D. However, the adverse effects of synthetic inhibitors highlight the need for safer natural alternatives. This study investigated the seaweed <em>Halopithys incurva</em> as a potential source of bioactive compounds with antioxidant and antidiabetic properties. Five extracts (n-hexane, dichloromethane, ethanol, methanol, and water) were prepared and subjected to chemical characterization and the estimation of total phenol content (TPC), total flavonoid content (TFC), and total tannin content (TTC). Six complementary <em>in vitro</em> antioxidant assays, together with <em>in vitro</em> antidiabetic assays were performed. The dichloromethane extract contained the highest levels of TPC, TFC, and TTC. The ethanol extract showed the strongest anti-DPPH (503.60 ± 2.14 mg TE/g dry extract) and anti-ABTS (668.55 ± 7.15 mg TE/g dry extract) activities, along with high activity in CUPRAC assay (632.13 ± 14.9 mg TE/g dry extract). The methanol extract showed the highest activity in both CUPRAC and PBD assays (949.33 ± 21.61 mg TE/g dry extract and 4.06 ± 0.011 mmol TE/g dry extract, respectively). Among the tested samples dichloromethane, ethanol, and methanol extracts demonstrated the most potent dual antidiabetic activity among the tested extracts. Nine compounds were identified for the first time from this species and subsequently screened as ligands in <em>in-silico</em> study to elucidate their molecular mechanisms. The results highlighted the strong antioxidant and antidiabetic potential of <em>H. incurva</em> extracts and emphasized the role of herniarin, toddalolactone, loliolide, and isololiolide as promising antidiabetic molecules.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"95 ","pages":"Article 104603"},"PeriodicalIF":4.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147386483","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}

{"title":"Sex-specific physiological-biochemical and multi-omics responses of Sargassum thunbergii to ocean acidification","authors":"Danrui Li ,&nbsp;Yuanyuan Wang ,&nbsp;Yan Zhao ,&nbsp;Xuexi Tang","doi":"10.1016/j.algal.2026.104615","DOIUrl":"10.1016/j.algal.2026.104615","url":null,"abstract":"<div><div>Ocean acidification (OA), driven by increasing atmospheric CO₂ concentrations, poses significant threats to the ecologically important intertidal macroalgae. Multiple previous studies have indicated species-specific responses to OA, the sex-specific physiological-biochemical responses and underlying molecular mechanisms in dioecious macroalgae remain poorly understood. In this study, we investigated the responses of male and female <em>Sargassum thunbergii</em> to acidification treatment (2000 ppm CO₂) by integrating physiological-biochemical, transcriptomic, and metabolomic analyses. Both sexes maintained photosynthetic performance, with increased maximum relative electron transport rates (rETRmax). Males exhibited a growth-oriented strategy, characterized by higher accumulation of storage compounds like triglycerides and up-regulation of genes related to the photosynthesis and biosynthesis pathways. In contrast, females displayed a survival-oriented strategy, with reduced carbon storage, increased soluble protein and phenolic substance contents, and up-regulation of genes related to defense- and stress-response pathways. These findings provided physiological-biochemical and molecular evidence for a growth and defense trade-off between male and female <em>S. thunbergii</em> under acidification treatment. Our study provided the mechanistic insights into the sex-specific responses of marine macroalgae to global climate change and highlighted the importance of accounting for sexual dimorphism in predicting the ecological resilience of intertidal macroalgae populations under future ocean conditions.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"95 ","pages":"Article 104615"},"PeriodicalIF":4.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147386485","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}

{"title":"Individual and combined effects of three phytohormones on lipid productivity and biodiesel quality in Nannochloropsis gaditana under nitrogen starvation","authors":"Wang Liufu ,&nbsp;Ma Xueyan ,&nbsp;Wen Haibo ,&nbsp;Huang Xuxiong ,&nbsp;Jin Wu ,&nbsp;Chen Wanwen ,&nbsp;Wang Yufeng ,&nbsp;Xu Pao","doi":"10.1016/j.algal.2026.104609","DOIUrl":"10.1016/j.algal.2026.104609","url":null,"abstract":"<div><div>To address the biomass-lipid trade-offs in microalgal biodiesel production, this study investigated biodiesel production using <em>Nannochloropsis gaditana</em> ffrc-1 by optimizing fulvic acid (FA), jasmonic acid (JA) and salicylic acid (SA) under nitrogen starvation, along with mechanistic insights into lipid biosynthesis. Using 20 mg/L FA under nitrogen starvation, the lipid content, biomass productivity and lipid productivity peaked at 30.50%, 0.48 g/L/day and 0.1450 g/L/day. With 20 mg/L JA under nitrogen starvation, the lipid content, biomass productivity and lipid productivity peaked at 31.50%, 0.74 g/L/day and 0.2335 g/L/day. Under nitrogen starvation with 2 mg/L SA, the lipid content, biomass productivity and lipid productivity peaked at 30.20%, 0.84 g/L/day and 0.2540 g/L/day. The combination of 22 mg/L FA, 17 mg/L JA and 2.4 mg/L SA by response surface methodology increased lipid productivity to 0.24 g/L/day under nitrogen starvation. The mRNA expression of lipid synthesis enzymes (acetyl-CoA carboxylase beta and diacylglycerol acyltransferase) was consistent with the trend of lipid accumulation. Moreover, the fatty acid profile and key biodiesel properties of <em>N. gaditana</em> ffrc-1 under nitrogen starvation with the supplementation of these phytohormones complied with international standards with improved cold flow performance. This indicated its promise as a sustainable biodiesel feedstock for cold-weather operations. In summary, this study proves that coordinated FA, JA, and SA application under nitrogen starvation effectively breaks the growth-lipid trade-off in <em>N. gaditana</em>, delivering both high lipid productivity and superior biodiesel cold-flow properties.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"95 ","pages":"Article 104609"},"PeriodicalIF":4.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147386396","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}

{"title":"Trade-offs between diversity and stability mediated by positive cohesion in sediment microbiomes under algal blooms","authors":"Ruyi Li ,&nbsp;Jianfeng Chen ,&nbsp;Qingyang Rao ,&nbsp;Shangsheng Sun ,&nbsp;Yihan Wang ,&nbsp;Misha Zhong ,&nbsp;Qingchuan Chou ,&nbsp;Meng Zhang ,&nbsp;Haojie Su ,&nbsp;Ping Xie","doi":"10.1016/j.algal.2026.104617","DOIUrl":"10.1016/j.algal.2026.104617","url":null,"abstract":"<div><div>Eutrophication-driven algal blooms represent profound disturbances that restructure aquatic ecosystems. However, the mechanisms by which sediment microbial diversity and species interactions govern community stability during such events remain inadequately resolved. Here, we tracked a natural dinoflagellate bloom in Lake Erhai, a eutrophying plateau lake in southwestern China, to assess pre- and post-bloom changes in sediment microbial communities using 16S rRNA and ITS sequencing. Our analyses revealed that algal blooms significantly reduced sediment microbial α-diversity and decreased community heterogeneity. Concurrently, co-occurrence networks exhibited tightened connectivity, evidenced by shorter average path lengths, increased edge density, and a pronounced rise in positive cohesion. Crucially, we found that sampling sites with higher species diversity have lower compositional stability (quantified as resistance to taxon turnover), while that with strong positive cohesion have higher compositional stability. In contrast, functional stability (metabolic potential) showed no significant relationship with either diversity or cohesion, indicating distinct regulatory mechanisms for compositional versus functional stability. These findings demonstrate a clear trade-off between species diversity and cooperative interactions in shaping compositional stability under bloom-induced stress. This work establishes that positive species cohesion, rather than diversity alone, is a critical mediator of microbial community resistance in sediments facing eutrophication pressures. It advances our mechanistic understanding of stability dynamics in microbiomes and underscores the need to integrate interaction networks when predicting ecosystem responses to anthropogenic disturbances.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"95 ","pages":"Article 104617"},"PeriodicalIF":4.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147386486","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}

{"title":"Biotreatment of table olive processing wastewater and simultaneous biomass production by a mixed culture of Picochlorum costavermella and indigenous microorganisms in laboratory and pilot-scale reactors","authors":"Stefania Patsialou ,&nbsp;Dimitris V. Vayenas ,&nbsp;Athanasia G. Tekerlekopoulou","doi":"10.1016/j.algal.2026.104602","DOIUrl":"10.1016/j.algal.2026.104602","url":null,"abstract":"<div><div>Table olive production generates hypersaline, phenol-rich effluents that pose a significant environmental challenge for their treatment, particularly for small-scale processing units. This study investigated the implementation of the halotolerant microalga <em>Picochlorum costavermella</em> as a single-step method for raw, non-sterilized table olive processing wastewater's (TOPW) biotreatment, coupled with biomass production. Autotrophic growth was first assessed in artificial saline media, followed by mixotrophic cultivation in TOPW. TOPW from the “Kalamon” and “Halkidiki” varieties was diluted with seawater, resulting in initial dissolved Chemical Oxygen Demand (d-COD) concentrations of approximately 500 and 1500 mg/L. In laboratory-scale reactors, biomass concentrations reached 740 mg/L, with removals up to 84% d-COD, 86% nitrate, 94% orthophosphate, and 84% total phenolics. Final d-COD was &lt;120 mg/L, meeting Greek discharge limits. In column photobioreactors, biomass reached 475 mg/L, with 79% d-COD and 96% phenolic removal. The mixed microalgae-indigenous microorganism culture effectively removed organic/inorganic pollutant while producing biomass rich in proteins (33%), lipids (25%), and carbohydrates (11%). Substantial decolorization (up to 83%) was also achieved, and column photobioreactors showed good scale-up potential with enhanced bioproduct accumulation.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"95 ","pages":"Article 104602"},"PeriodicalIF":4.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147386547","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}

{"title":"Hyperproduction of lutein and protein in a novel yellow mutant of Chlorella sorokiniana via modulation of carbon‑nitrogen metabolism under high-cell-density heterotrophic cultivation","authors":"Yucheng Chen ,&nbsp;Zehao Qiu ,&nbsp;Wen Zhang ,&nbsp;Xinxin Huang ,&nbsp;Ruijuan Ma ,&nbsp;Baobei Wang ,&nbsp;Shih-Hsin Ho ,&nbsp;Jianfeng Chen ,&nbsp;Youping Xie","doi":"10.1016/j.algal.2026.104626","DOIUrl":"10.1016/j.algal.2026.104626","url":null,"abstract":"<div><div><em>Chlorella sorokiniana</em> is capable of high-cell-density heterotrophic cultivation, endowing it with exceptional potential for large-scale, efficient lutein production. However, its industrial application has been hindered by low lutein content and the inability to precisely control carotenoid composition. To address these limitations, a chlorophyll-deficient and lutein-enriched yellow mutant <em>C. sorokiniana</em> MT03 was employed to investigate the effects of carbon–nitrogen (C/N) ratio modulation on lutein and protein production under heterotrophic conditions. Systematic optimization identified a C/N ratio of 16 as optimal, resulting in marked enhancement of both lutein and protein accumulation. Integrated physiological and transcriptomic analyses demonstrated that carbon depletion combined with nitrogen repletion coordinately regulated central carbon metabolism, macromolecular biosynthesis, heme homeostasis, and carotenoid biosynthetic pathways. Notably, key genes involved in fatty acid biosynthesis, starch degradation, amino acid biosynthesis, and carotenoid formation were significantly upregulated, highlighting the tight integration of nitrogen availability with carbon partitioning. Heme accumulation was found to enhance CYP97-mediated lutein synthesis, further linking nitrogen status to carotenogenic flux. A two-stage cultivation strategy, comprising (I) fed-batch growth for high-cell-density biomass production, followed by (II) carbon-depleted and nitrogen-replete conditions to trigger lutein and protein synthesis, was successfully implemented in a 5-L bioreactor. This approach yielded a final biomass concentration of 184.46 g/L, with volumetric titers of 481.63 mg/L lutein and 76.31 g/L protein, surpassing most values reported in the literature. These results demonstrate that rational C/N metabolic regulation effectively redirects carbon flux toward target metabolites, providing a scalable and industrially viable platform for the co-production of lutein and protein in microalgae.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"95 ","pages":"Article 104626"},"PeriodicalIF":4.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147386549","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}

{"title":"Efficient cationic dodecenyl succinic anhydride modified starch-based flocculant with a broad salinity tolerance: preparation, microalgae harvesting and flocculation mechanisms","authors":"Liu Yang ,&nbsp;Yaohui You ,&nbsp;Chenming Wang ,&nbsp;Wenhua Yang ,&nbsp;Li Zhao ,&nbsp;Han Xiao ,&nbsp;Jie Sun ,&nbsp;Xiangxiang Zhang","doi":"10.1016/j.algal.2026.104565","DOIUrl":"10.1016/j.algal.2026.104565","url":null,"abstract":"<div><div>The use of flocculation to harvest microalgae from the living environment is efficient and energy-saving; however, it is prone to microalgal biomass contamination and sensitive to the environmental salinity. In the present study, cationic dodecenyl succinic anhydride-modified starch (CDCS) was prepared for harvesting microalgae with various salinities. SEM, XRD, FTIR, ¹H NMR, TG substitution degree, contact angle and zeta potential results confirmed the successful synthesis of CDCS with amphiphilic polyelectrolyte and hydrophobically associating polymer properties. As a comparison, cationic starch (CCS) could only flocculate microalgae at relatively low salinities. In contrast, CDCS could harvest microalgae in 3, 10, 15 and 20 ppt salinity environments at dosages of 3, 10, 25 and 100 mg/L, respectively. Hydrodynamic diameter, viscosity and zeta potential measurements of flocculants at different salinities demonstrated that CDCS could maintain relatively stretched molecular conformations and more cationic charges in high-salinity environments. Analysis of zeta potential, floc morphology and floc size suggested that CDCS could form large three-dimensional mesh flocs with strong anti-shear and reflocculation abilities through charge neutralization, bridging adsorption, hydrophobic forces, netting and sweeping. Additionally, microalgal dissolved/bound extracellular organic matter (DEOM/BEOM) was extracted and flocculated by CCS and CDCS for analysis of the three-dimensional fluorescence, protein and polysaccharide contents. Results showed that CDCS with a broad salinity tolerance tended to interact with BEOM, therefore promoting the formation and sedimentation of microalgal flocs. Finally, cost estimates indicated that CDCS can save 40%–90% of the harvesting costs at different salinities compared to CCS.</div></div>","PeriodicalId":7855,"journal":{"name":"Algal Research-Biomass Biofuels and Bioproducts","volume":"95 ","pages":"Article 104565"},"PeriodicalIF":4.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147386551","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}