This study explores the hydrothermal liquefaction of three marine macroalgae, Halimeda gracilis, Sargassum cinereum, and Solieria robusta for bio-crude production, emphasizing their potential as renewable sources of bioactive compounds. Hydrothermal liquefaction was conducted in a high-pressure batch reactor at 300 °C for 30 min at a biomass-to-water ratio of 1:10 (w/v) under an inert nitrogen atmosphere to prevent oxidation. Proximate analysis revealed notable differences in biocrude yield among the species. S. cinereum produced the highest bio-crude yield (15.57%), accounting for 48.47% of total biomass. S. robusta has the highest carbohydrate content at 82 g/100 g. The bio-crude extracts were extensively characterized by UV–visible spectroscopy, GC–MS, HPLC, FT-IR, and NMR techniques. This analysis identified a diverse range of bioactive compounds including phenolic acids, flavonoids, alkaloids, hydrocarbons, fatty acids, and sterols. Through computer modeling, key bioactive compounds were identified in each species. H. gracilis contains 4-(3-ethyl-1-hydroxyhexan-2-yl)-3-(hydroxymethyl)-32-methoxy-10-oxo-2-pentyldotriacontanimidic acid (C47H93NO5), S. cinereum was found to contains (14E,17E,20E,22E)-31-butyl-2-((2(hydroxymethoxy)methoxy)ethoxy)methyl)nonatriaconta-14,17,20,22-tetraene-1,33,35,37-tetraol (C4H90O8), and S. robusta contained (E)-18-cyclopentyl-2-(10-((2-hydroperoxyvinyl) amino)decyl)-11,14-dihydroxyoctadecanoic acid (C35H57NO6).The antimicrobial efficacy of the bio-crudes was evaluated, and they demonstrated concentration-dependent antibacterial activity against a range of bacterial strains. Notably, S. robusta exhibited the strongest inhibition of Streptococcus pneumoniae and Staphylococcus aureus, thereby highlighting its significant antibacterial potential. In contrast, S. cinereum showed antifungal activity against Candida albicans, whereas S. robusta displayed limited antifungal efficacy. In addition to antimicrobial testing, the cytotoxicity of the bio-crudes was assessed against A549 lung cancer cells using the MTT assay. S. robusta demonstrated the most potent anticancer activity, with an IC50 value of 45.32 µg mL−1, significantly reducing cancer cell viability. H. gracilis and S. cinereum also exhibited notable anticancer properties, with IC50 values of 67.65 µg mL−1 and 74.23 µg mL−1, respectively. The novelty of this study lies in its innovative approach of utilizing bio-crude as a potential pharmaceutical resource, which presents a new paradigm for bio-crude applications. These findings suggest that these seaweeds, especially Solieria robusta, may play a significant role in the development of novel anticancer therapies, particularly in the treatment of lung cancer. Graphical Abstract Graphical abstract for hydrothermal liquefaction-derived bio-crude from seaweeds: a novel source of antimicrobial and anticancer agents.

Influence of Algal Biomass Chemical Composition on Hydrothermal Liquefaction Efficiency and Its Implications for A549 Cell Line Cytotoxicity

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发表日期：

2025年4月28日

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T. Ajith,
Mythili Ravichandran,
Salim Manoharadas,
Jameel Al-Tamimi,
Sonaimuthu Mohandoss,
R. Dineshkumar,
S. R. Sivakumar

摘要

This study explores the hydrothermal liquefaction of three marine macroalgae, Halimeda gracilis, Sargassum cinereum, and Solieria robusta for bio-crude production, emphasizing their potential as renewable sources of bioactive compounds. Hydrothermal liquefaction was conducted in a high-pressure batch reactor at 300 °C for 30 min at a biomass-to-water ratio of 1:10 (w/v) under an inert nitrogen atmosphere to prevent oxidation. Proximate analysis revealed notable differences in biocrude yield among the species. S. cinereum produced the highest bio-crude yield (15.57%), accounting for 48.47% of total biomass. S. robusta has the highest carbohydrate content at 82 g/100 g. The bio-crude extracts were extensively characterized by UV–visible spectroscopy, GC–MS, HPLC, FT-IR, and NMR techniques. This analysis identified a diverse range of bioactive compounds including phenolic acids, flavonoids, alkaloids, hydrocarbons, fatty acids, and sterols. Through computer modeling, key bioactive compounds were identified in each species. H. gracilis contains 4-(3-ethyl-1-hydroxyhexan-2-yl)-3-(hydroxymethyl)-32-methoxy-10-oxo-2-pentyldotriacontanimidic acid (C₄₇H₉₃NO₅), S. cinereum was found to contains (14E,17E,20E,22E)-31-butyl-2-((2(hydroxymethoxy)methoxy)ethoxy)methyl)nonatriaconta-14,17,20,22-tetraene-1,33,35,37-tetraol (C₄H₉₀O₈), and S. robusta contained (E)-18-cyclopentyl-2-(10-((2-hydroperoxyvinyl) amino)decyl)-11,14-dihydroxyoctadecanoic acid (C₃₅H₅₇NO₆).The antimicrobial efficacy of the bio-crudes was evaluated, and they demonstrated concentration-dependent antibacterial activity against a range of bacterial strains. Notably, S. robusta exhibited the strongest inhibition of Streptococcus pneumoniae and Staphylococcus aureus, thereby highlighting its significant antibacterial potential. In contrast, S. cinereum showed antifungal activity against Candida albicans, whereas S. robusta displayed limited antifungal efficacy. In addition to antimicrobial testing, the cytotoxicity of the bio-crudes was assessed against A549 lung cancer cells using the MTT assay. S. robusta demonstrated the most potent anticancer activity, with an IC₅₀ value of 45.32 µg mL⁻¹, significantly reducing cancer cell viability. H. gracilis and S. cinereum also exhibited notable anticancer properties, with IC₅₀ values of 67.65 µg mL⁻¹ and 74.23 µg mL⁻¹, respectively. The novelty of this study lies in its innovative approach of utilizing bio-crude as a potential pharmaceutical resource, which presents a new paradigm for bio-crude applications. These findings suggest that these seaweeds, especially Solieria robusta, may play a significant role in the development of novel anticancer therapies, particularly in the treatment of lung cancer.

Graphical Abstract

Graphical abstract for hydrothermal liquefaction-derived bio-crude from seaweeds: a novel source of antimicrobial and anticancer agents.