Efficient downstream processing of second-generation lactic acid from lignocellulosic waste using aqueous two-phase...

Area of Science:

• Biotechnology and Industrial Microbiology
• Biochemical Engineering
• Waste Valorization

Background:

• Lignocellulosic biomass offers a sustainable feedstock for biotechnological processes.
• Efficient downstream processing for lactic acid from second-generation feedstocks remains a challenge.
• Olive leaves represent an abundant, low-cost waste material suitable for bioprocessing.

Purpose of the Study:

• To develop and evaluate a two-step downstream process for lactic acid recovery from fermented olive leaves.
• To assess the efficiency of aqueous two-phase extraction and activated carbon purification.
• To determine the yield and purity of the recovered lactic acid.

Main Methods:

• Aqueous two-phase extraction using an ethanol/ammonium sulfate system was employed for initial lactic acid recovery.
• Activated carbon was used as a secondary purification step.
• High-Performance Liquid Chromatography (HPLC), Fourier-Transform Infrared (FT-IR) spectroscopy, and Proton Nuclear Magnetic Resonance (¹H-NMR) spectroscopy were used for analysis.

Main Results:

• The two-step process achieved a lactic acid yield of 70.02% in the first stage and 88.91% in the purification stage.
• The final lactic acid purity reached 90.17%.
• Direct extraction from unfiltered medium effectively removed up to 95.23% of bacterial cells.

Conclusions:

• A cost-effective and efficient downstream process for lactic acid recovery from fermented olive leaves was successfully established.
• This method highlights the potential of utilizing waste lignocellulosic biomass for sustainable lactic acid production.
• The recovered lactic acid was qualitatively identified, confirming its suitability for further applications.