Growth-promoting bacteria double eicosapentaenoic acid yield in microalgae.

Area of Science:

• * Microbiology
• * Marine Biotechnology
• * Algal Aquaculture

Background:

• * Microalgae are crucial for sustainable food, feed, and biofuel production.
• * Algae-associated bacteria can profoundly impact microalgal yields, either positively or negatively.
• * Nannochloropsis oceanica is a high-yield microalga, notable for its rich eicosapentaenoic acid (EPA) content.

Purpose of the Study:

• * To isolate, identify, and select effective probiotic bacterial strains associated with Nannochloropsis oceanica.
• * To evaluate the impact of these probiotic bacteria on microalgal growth, biomass, and EPA production.

Main Methods:

• * Isolation and identification of bacteria associated with Nannochloropsis oceanica.
• * Co-cultivation experiments to assess the effects of bacterial supplementation on microalgal growth parameters.
• * Analysis of biomass yield, cell density, and eicosapentaenoic acid (EPA) content.

Main Results:

• * Co-cultivation with ten selected bacterial strains significantly enhanced Nannochloropsis oceanica culture density and biomass by 2.2- and 1.56-fold, respectively.
• * Eicosapentaenoic acid (EPA) content in microalgae increased up to 2.25-fold, reaching 39.68% of total fatty acids.
• * Probiotic bacteria demonstrated beneficial traits such as nitrogen fixation, growth hormone production, and phosphorus solubilization.

Conclusions:

• * Supplementation with specific probiotic bacteria can significantly enhance the biomass and EPA production of Nannochloropsis oceanica.
• * The identified probiotic bacteria possess multiple traits conducive to stimulating microalgal growth.
• * These findings support the use of probiotic bacteria as a strategy for optimizing microalgal cultivation for commercial applications.