Construction and transcriptomic analysis of salinity-induced lipid-rich flocculent microalgae

Area of Science:

• Biotechnology
• Algal Biology
• Sustainable Energy

Background:

• Microalgae cultivation for biofuels faces challenges in cost-effective nutrient sourcing and harvesting.
• Developing efficient methods for producing lipid-rich microalgal biomass is crucial for sustainable biofuel production.

Purpose of the Study:

• To investigate the effects of saline wastewater on the cultivation of Chlorella pyrenoidosa for producing lipid-rich flocculent microalgae particles.
• To elucidate the underlying molecular mechanisms of lipid accumulation in microalgae under salt stress.

Main Methods:

• Cultivation of Chlorella pyrenoidosa in a stirred photobioreactor with varying influent salinities (0-3%).
• Analysis of microalgal particle size, sedimentation rate, and lipid content.
• Transcriptome analysis to identify differentially expressed genes (DEGs) under salt stress.
• Enrichment analysis of DEGs to understand metabolic pathway alterations.

Main Results:

• Saline wastewater cultivation successfully produced lipid-rich flocculent microalgae particles.
• Increased salinity correlated with larger particle size, higher sedimentation rates, and enhanced lipid accumulation.
• Transcriptome analysis revealed increased gene expression related to fatty acid biosynthesis under salt stress.
• Key genes involved in lipid and exopolysaccharide (EPS) synthesis were preliminarily identified.

Conclusions:

• Salinity is a significant factor in enhancing lipid production and flocculation in Chlorella pyrenoidosa.
• The study provides insights into the genetic mechanisms driving lipid accumulation in microalgae exposed to saline conditions.
• Findings support the potential for genetic engineering to optimize lipid-rich microalgal particle production for biofuels.