Friends or foes? Allelopathic effects within a 3-microalgal consortium

Area of Science:

• * Microbiology and Biotechnology
• * Algal Physiology and Biochemistry

Background:

• * Allelopathic interactions are crucial in microbial communities.
• * Understanding chemical signaling in microalgae is key for optimizing cultivation.

Purpose of the Study:

• * Investigate allelopathic effects in a consortium of Tetradesmus obliquus, Chlamydomonas reinhardtii, and Auxenochlorella protothecoides.
• * Elucidate how intra- and interspecific chemical signals modulate algal growth and biomass composition.
• * Assess the role of extracellular vesicles in algal communication.

Main Methods:

• * Cultivation of monocultures and mixed-species microalgae.
• * Analysis of spent media using Total X-ray Fluorescence (TXRF) and Fourier-transform infrared spectroscopy (FTIR).
• * Detection of extracellular vesicles (algosomes) using Dynamic Light Scattering (DLS).

Main Results:

• * Species-specific, non-deleterious responses to allelopathic signals observed.
• * Increased growth rates in C. reinhardtii and A. protothecoides; enhanced cell density in T. obliquus.
• * Allelopathy induced morphological changes (reduced colony size) in T. obliquus and shifted biomass towards protein and lipid accumulation.

Conclusions:

• * Positive allelopathic signals can enhance microalgal productivity and modify biomass quality.
• * Extracellular vesicles are implicated in mediating these allelopathic interactions.
• * Findings provide insights for optimizing microalgal biotechnological cultivation.