Transcriptomic insights into dynamically optimized batch feeding strategies for carbon fixation mechanisms in CO₂...

Area of Science:

• Biotechnology
• Environmental Science
• Microalgal Cultivation

Background:

• Efficient operation of CO2 absorption-microalgae conversion (CAMC) systems is crucial for carbon capture.
• Matching nutrient supply with cellular demand is key to optimizing microalgal productivity.

Purpose of the Study:

• To investigate the impact of different batch feeding strategies on microalgal growth and metabolism in CAMC systems.
• To elucidate the molecular mechanisms behind enhanced microalgal performance under optimized feeding conditions.

Main Methods:

• Implementation of various batch feeding strategies for microalgae cultivation.
• Biomass concentration, bicarbonate utilization, and carbon fixation measurements.
• Transcriptomic analysis to understand gene expression changes.

Main Results:

• A specific batch feeding strategy (small, large, small amounts during adaptation, growth, and stable phases) outperformed direct nutrient addition.
• This strategy led to significant increases in biomass concentration (9.8%), bicarbonate utilization efficiency (30.6%), and carbon fixation capability (12.0%).
• Yields of chlorophyll (27.5%), carotenoids (10.1%), and carbohydrates (31.3%) were substantially enhanced.

Conclusions:

• The optimized batch feeding strategy effectively enhances microalgal growth and carbon fixation in CAMC systems.
• Transcriptomic analysis revealed that batch feeding up-regulates key metabolic pathways, including ribosome biogenesis, carbohydrate synthesis, the TCA cycle, and photosynthesis.
• These molecular changes promote greater energy allocation towards carbon fixation and the accumulation of valuable biomass components.