Improvement of exopolysaccharide production by Porphyridium marinum

Area of Science:

• Marine Biotechnology
• Microbial Physiology
• Biopolymer Production

Background:

• Porphyridium marinum is a microalga capable of producing exopolysaccharides (EPS).
• Optimizing cultivation conditions is crucial for maximizing EPS yield and productivity.
• Existing media and culture parameters may limit the efficient production of EPS.

Purpose of the Study:

• To optimize exopolysaccharide (EPS) production by Porphyridium marinum.
• To evaluate a new nutrient medium (Pm) for enhanced EPS yield.
• To determine optimal irradiance and temperature for improved EPS production kinetics.

Main Methods:

• Cultivation of Porphyridium marinum in photobioreactors using modified Provasoli medium (P) and a new medium (Pm).
• Elemental analysis of the Pm medium (N0.0205S0.0597P0.005).
• Monitoring photosynthetic activity, growth, and EPS production under varying irradiance and temperature.
• Comparison of batch and semi-continuous culture strategies.

Main Results:

• The Pm medium increased EPS concentration to 2.5 g/L without altering EPS structure or productivity.
• Optimal conditions identified: 360 µmol photons m⁻² s⁻¹ irradiance and 28°C.
• Semi-continuous culture under optimal conditions achieved a 55% increase in EPS process productivity (0.031 g/h vs. 0.020 g/h in batch culture).

Conclusions:

• The developed Pm medium significantly enhances EPS concentration in Porphyridium marinum cultures.
• Optimized irradiance and temperature, coupled with semi-continuous cultivation, substantially improve EPS process productivity.
• These findings provide a foundation for scalable and efficient exopolysaccharide production from Porphyridium marinum.