Selecting reliable and robust freshwater macroalgae for biomass applications.

Area of Science:

• * Aquatic Botany
• * Biomass Energy
• * Algal Biotechnology

Background:

• * Increasing demand for algal biofuels and bioremediation necessitates identifying suitable freshwater macroalgae for intensive cultivation.
• * Current knowledge lacks identified target species for large-scale freshwater macroalgae production.

Purpose of the Study:

• * To compare productivity, growth, and biochemical composition of key freshwater macroalgae genera.
• * To select a primary target species for large-scale cultivation.
• * To assess the selected species' competitive ability against other candidates.

Main Methods:

• * Cultivation of Oedogonium, Cladophora, and Spirogyra under varying conditions, including CO₂ addition and aeration.
• * Biochemical analysis of biomass for ash, water, carbon content, and higher heating value.
• * Bi-culture and polyculture experiments to evaluate competitive interactions at different stocking densities.

Main Results:

• * Oedogonium exhibited superior productivity (8.0 g AFDW m⁻² day⁻¹), lower ash (3-8%), lower water content, higher carbon content (45%), and greater bioenergy potential (20 MJ/kg).
• * Oedogonium consistently outperformed Cladophora and Spirogyra in productivity across different cultivation treatments.
• * Oedogonium demonstrated strong competitive dominance, increasing to over 82% proportion in mixed cultures within three weeks.

Conclusions:

• * Oedogonium is identified as a highly promising freshwater macroalgae species for large-scale production due to its productivity and bioenergy potential.
• * Its competitive dominance suggests suitability for mixed cultivation systems and efficient biomass generation.
• * Freshwater macroalgae represent an underutilized resource with significant potential for biomass applications in bioenergy and bioremediation.