Altered Microbiome Leads to Significant Phenotypic and Transcriptomic Differences in a Lipid Accumulating Chlorophyte

Area of Science:

• Biotechnology
• Microbiology
• Algal Biotechnology

Background:

• Economically viable microalgae cultivation for products like biodiesel faces challenges.
• Microalgal productivity is affected by operational parameters, but microbe-microbe interactions are understudied.

Purpose of the Study:

• To investigate the impact of microbial community structure on the growth and triacylglycerol (TAG) accumulation of an oleaginous marine alga.
• To identify specific microbial players and their roles in algal productivity.

Main Methods:

• Characterization of a Chlorella spp. C596 culture as a microbial community.
• Perturbation experiments to assess phenotypic changes in growth and TAG accumulation.
• Illumina 16S rRNA amplicon sequencing and random shotgun transcriptomics for community and algal gene expression analysis.

Main Results:

• Microbial community perturbations significantly altered algal growth rates (2.4-fold) and TAG accumulation (2.5-fold).
• Fast growth correlated with the presence of Ruegeria and Rhodobacter bacterial species.
• Slower-growing consortia showed upregulated photosynthesis and resource scavenging genes, and downregulated transcription/translation genes in Chlorella.

Conclusions:

• Microalgal bioreactor productivity is significantly influenced by associated microbial communities.
• Symbiotic interactions play critical roles in nutrient cycling (nitrogen, carbon) and stress response in microalgal cultures.
• Harnessing these microbial interactions offers potential for enhanced microalgal biotechnology.