Simultaneous production of algal biomass and lipid by heterotrophic cultivation of linoleic acid-rich oleaginous microalga Chlorella sorokiniana using high acetate dosage

• Published in: Bioresource technology 2024-05, Vol.399, p.130566-130566, Article 130566
• Main Authors: Gong, Guiping, Liu, Linpei, Wu, Bo, Li, Jianting, He, Mingxiong, Hu, Guoquan
• Format: Article
• Language: English
• Subjects: Acetate bioconversion; Heterotrophic repeat fed-batch; Microalgal biomass; Microbial lipids; Trophic mode
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2024.130566

[Display omitted] •C. sorokiniana showed superior tolerance capacity on high acetate dosage up to 30 g/L.•Heterotrophy benefits to algal growth and lipogenesis when supplying 20 g/L acetate.•Inhibition of photosynthesis led to poor mixotrophic growth under 20 g/L acetate.•Heterotrophy produced superior amino acid profiling and more linoleic acid (50%).•Heterotrophic repeat fed-batch mode resulted in 23.4 g/L biomass and 7.0 g/L lipid. The low-cost carbon source, acetate, was utilized to feed a linoleic acid-rich Chlorella sorokiniana for microalgal biomass and lipid accumulation. Remarkably high tolerance capability to high acetate dosage up to 30 g/L was observed, with heterotrophy being the preferred trophic mode for algal growth and lipogenesis when supplemented 20 g/L acetate. Transcriptome analysis revealed a marked activation of pathways involved in acetate bioconversion and lipogenesis upon exposure to high-level of acetate. However, the enhancement of photorespiration inhibited photosynthesis, which ultimately led to a decrease in biomass and lipid under mixotrophy. Heterotrophic acetate-feeding generated more superior amino acid profiling of algal biomass and a predominant linoleic acid content (50 %). Heterotrophic repeat fed-batch strategy in 5 L fermenter significantly increased the growth performance and lipid titer, with the highest levels achieved being 23.4 g/L and 7.0 g/L, respectively. This work provides a viable approach for bio-products production through acetate-based heterotrophic algal cultivation.