Biotransformation of ethinylestradiol by microalgae

Area of Science:

• Environmental Microbiology
• Biotechnology
• Ecotoxicology

Background:

• Ethinylestradiol (EE) is a potent synthetic estrogen found in wastewater.
• Pharmaceuticals in the environment pose risks to aquatic ecosystems.
• Biotransformation by microalgae offers a potential remediation strategy.

Purpose of the Study:

• To evaluate the biotransformation potential of various microalgae strains on ethinylestradiol (EE).
• To identify microalgae species capable of degrading EE.
• To characterize the transformation products and yields.

Main Methods:

• Screening of 11 microalgae strains for EE biotransformation capability.
• Identification and quantification of EE transformation products using analytical techniques.
• Optimization of algal density for enhanced biotransformation.

Main Results:

• Seven of the 11 tested microalgae strains were ineffective in biotransforming EE.
• Selenastrum capricornutum, Scenedesmus quadricauda, Scenedesmus vacuolatus, and Ankistrodesmus braunii demonstrated EE biotransformation.
• S. capricornutum converted EE into ethinylestradiol glucoside (40% yield), 3-beta-D-glucopyranosyl-2-hydroxyethinylestradiol (5% yield), and 3-beta-D-glucopyranosyl-6beta-hydroxyethinyl estradiol (5% yield).
• S. quadricauda produced 17alpha-ethinyl-1,4-estradien-10,17beta-diol-3-one (12% yield), and A. braunii produced 6-alpha-hydroxy-ethinylestradiol (25% yield).
• Under optimal conditions, S. capricornutum achieved a 92% yield of ethinylestradiol glucoside.

Conclusions:

• Microalgae, particularly Selenastrum capricornutum, show significant potential for the biotransformation of ethinylestradiol.
• The identification of specific transformation products provides insight into the degradation pathways.
• Optimizing microalgal density can substantially enhance the efficiency of EE remediation.