Astaxanthin(AXT)from microalgae is widely recognized for its potent antioxidant properties,yet the biological potential of bacterial AXT remains poorly characterized.This study provides the first integrative evaluatio...Astaxanthin(AXT)from microalgae is widely recognized for its potent antioxidant properties,yet the biological potential of bacterial AXT remains poorly characterized.This study provides the first integrative evaluation of free and nanoencapsulated AXT obtained from bacteria Paracoccus carotinifaciens,combining sustainable extraction,advanced formulation,antimicrobial assays,and in silico target prediction.A green dimethyl carbonate(DMC)extraction process was optimized by assessing temperature,extraction time,and solid-liquid ratio,achieving high AXT recovery(>85%)with efficient solvent recyclability.The AXT-rich extracts were incorporated into poloxamer-407 nanoparticles producing stable colloidal systems with controlled size(≈230-340 nm),low polydispersity,and negative surface charge,supporting their suitability for biological applications.Antimicrobial assays revealed that neither free nor nanoencapsulated AXT exhibited antibacterial activity against Escherichia coli,Enterococcus faecalis,or Staphylococcus aureus.However,nanoencapsulation selectively enhanced antifungal activity,yielding weak but fungistatic effects against Trichophyton rubrum(MIC=125μg/mL),whereas Candida albicans remained unaffected.To clarify this specificity,in silico screening identified key T.rubrum targets,primarily enzymes related to tryptophan metabolism and acetylation pathways.The results demonstrate that although Paracoccus-derived AXT lacks antibacterial activity,it exhibits a formulationenhanced and highly selective fungistatic effect.Importantly,the absence of antibacterial action represents a safety advantage,as it reduces the risk of disrupting beneficial microbiota or selecting for antibiotic resistance,features that are critical for food applications.These findings suggest that Paracoccus-derived AXT may be more appropriate for microbiota-compatible applications,given its lack of antibacterial activity,rather than for use as a broad-spectrum antimicrobial compound.展开更多
基金supported by grants from ANID/FONDECYT/1250170 and ANID/FOVI/250065.
文摘Astaxanthin(AXT)from microalgae is widely recognized for its potent antioxidant properties,yet the biological potential of bacterial AXT remains poorly characterized.This study provides the first integrative evaluation of free and nanoencapsulated AXT obtained from bacteria Paracoccus carotinifaciens,combining sustainable extraction,advanced formulation,antimicrobial assays,and in silico target prediction.A green dimethyl carbonate(DMC)extraction process was optimized by assessing temperature,extraction time,and solid-liquid ratio,achieving high AXT recovery(>85%)with efficient solvent recyclability.The AXT-rich extracts were incorporated into poloxamer-407 nanoparticles producing stable colloidal systems with controlled size(≈230-340 nm),low polydispersity,and negative surface charge,supporting their suitability for biological applications.Antimicrobial assays revealed that neither free nor nanoencapsulated AXT exhibited antibacterial activity against Escherichia coli,Enterococcus faecalis,or Staphylococcus aureus.However,nanoencapsulation selectively enhanced antifungal activity,yielding weak but fungistatic effects against Trichophyton rubrum(MIC=125μg/mL),whereas Candida albicans remained unaffected.To clarify this specificity,in silico screening identified key T.rubrum targets,primarily enzymes related to tryptophan metabolism and acetylation pathways.The results demonstrate that although Paracoccus-derived AXT lacks antibacterial activity,it exhibits a formulationenhanced and highly selective fungistatic effect.Importantly,the absence of antibacterial action represents a safety advantage,as it reduces the risk of disrupting beneficial microbiota or selecting for antibiotic resistance,features that are critical for food applications.These findings suggest that Paracoccus-derived AXT may be more appropriate for microbiota-compatible applications,given its lack of antibacterial activity,rather than for use as a broad-spectrum antimicrobial compound.
