Microbial Application to Improve Olive Mill Wastewater Phenolic Extracts.

Area of Science:

• Food Chemistry
• Biotechnology
• Environmental Science

Background:

• Olive mill wastewater (OMW) is rich in bioactive compounds, notably hydroxytyrosol, known for its antioxidant properties.
• Health benefits associated with olive polyphenols drive interest in extracting and concentrating these compounds.

Purpose of the Study:

• To develop a method for increasing hydroxytyrosol levels in OMW extracts using microbial enzymatic activity.
• To identify effective adsorbent resins and microbial strains for hydroxytyrosol enrichment.

Main Methods:

• Screening of four commercial adsorbent resins for selective recovery of phenolic compounds.
• Assessing beta-glucosidase and esterase activity of microbial strains including *Wickerhamomyces anomalus*, *Lactiplantibacillus plantarum*, and *Saccharomyces cerevisiae*.
• Conducting bioconversion tests using microbial culture broths and pellets to enhance hydroxytyrosol concentration.

Main Results:

• The SP207 resin demonstrated high efficiency in recovering hydroxytyrosol, tyrosol, oleuropein, and total phenols.
• *Wickerhamomyces anomalus* exhibited superior enzymatic performance among the tested strains.
• Pellets of *W. anomalus* and *L. plantarum* were most effective in increasing hydroxytyrosol levels in the phenolic extract.

Conclusions:

• Microbial enzymatic activity offers a viable strategy for enhancing hydroxytyrosol content in OMW phenolic extracts.
• The use of specific microbial strains and adsorbent resins can lead to enriched, functional OMW extracts.
• Further research into formulations utilizing multifunctional microorganisms for OMW extract valorization is warranted.