Production of lipases by solid state fermentation using vegetable oil-refining wastes

Area of Science:

• Biotechnology
• Environmental Microbiology
• Enzyme Engineering

Background:

• Industrial wastes rich in fats are often underutilized.
• Wastewater sludges harbor diverse microbial communities capable of producing valuable enzymes.
• Solid-state fermentation (SSF) offers a sustainable approach for enzyme production.

Purpose of the Study:

• To produce lipases using a microbial consortium from wastewater sludge grown on industrial solid wastes.
• To optimize lipase extraction from the solid matrix.
• To characterize the activity and stability of the produced lipases.

Main Methods:

• Cultivation of a microbial consortium from wastewater sludge on fat-rich industrial waste under thermophilic conditions (45°C for 20 days) in 4.5-L reactors.
• Extraction of lipases using Tris-HCl buffer (100mM, pH 8.0) and a cationic surfactant (cetyltrimethylammonium chloride).
• Optimization of surfactant and buffer concentrations using a full factorial experimental design.
• Determination of optimal temperature and pH for lipase activity.
• Quantification of lipolytic activity in the solid samples.

Main Results:

• Lipases were successfully produced by a microbial consortium under thermophilic solid-state fermentation conditions.
• Extraction using Tris-HCl and cetyltrimethylammonium chloride yielded active lipases.
• Optimal activity for the extracted lipases was observed between 61-65°C and pH 7.7-9.
• Lipolytic activity reached up to 120,000 UA/g of dry matter, significantly exceeding previously reported values for SSF.

Conclusions:

• Thermophilic microbial consortia can effectively produce high-activity lipases from industrial solid wastes.
• The developed extraction method efficiently recovers lipases from the solid matrix.
• These findings highlight the potential of using industrial wastes as a substrate for enzyme production and valorization, positioning them as effective biocatalysts.