A comparative study between fungal pellet- and spore-assisted microalgae harvesting methods for algae bioflocculation

Area of Science:

• Biotechnology
• Environmental Science
• Microbiology

Background:

• Microalgal harvesting is crucial for biofuel and bioproduct applications.
• Fungi-assisted bioflocculation offers an efficient and cost-effective alternative to conventional methods.
• Systematic comparisons between fungal spore-assisted (FSA) and fungal pellet-assisted (FPA) microalgal harvesting are lacking.

Purpose of the Study:

• To compare the efficiency of FSA and FPA methods for harvesting Chlorella sp.
• To identify critical parameters influencing microalgal harvesting efficiency using fungi.
• To evaluate the potential of FPA as a superior microalgal bioflocculation method.

Main Methods:

• Co-cultivation of Chlorella sp. with Penicillium sp. spores (FSA) or pellets (FPA).
• Optimization of critical parameters: temperature, glucose concentration, pH, and fungi:algae ratio.
• Quantification of flocculation efficiency and harvesting time.

Main Results:

• FSA achieved 99% flocculation efficiency under specific conditions (40°C, 5g glucose/L, 1.1×10⁴ spores/mL) but required 28 hours.
• FPA harvested 98.26% of algae cells in just 2.5 hours at 34°C, pH 4.0, and a 1:2 fungi:algae ratio.
• FPA required half the carbon input compared to FSA.

Conclusions:

• Fungal pellet-assisted (FPA) microalgal harvesting is significantly faster and more resource-efficient than fungal spore-assisted (FSA) harvesting.
• FPA demonstrates greater promise for development into a highly effective microalgal bioflocculation method due to its speed and lower glucose requirements.
• Optimization of parameters like temperature, pH, and fungi:algae ratio is key for maximizing bioflocculation efficiency in both methods.