Protein and lysine improvement harnessed by a signal chain of red light-emitting diode light in Chlorella pyrenoidosa

• Published in: Bioresource technology Vol. 414; p. 131620
• Main Authors: Wang, Jia, Sun, Han, Mou, Haijin, Yang, Shufang
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.12.2024
• Subjects: C. pyrenoidosa; Ca2+-CaM; Diaminopimelic acid pathway; Lysine synthesis; Pyruvate metabolism; Red light signal chain; Ca2+-CaM; Lysine synthesis; Red light signal chain; Diaminopimelic acid pathway; Pyruvate metabolism; C. pyrenoidosa; Ca(2+)-CaM
• ISSN: 0960-8524; 1873-2976; 1873-2976
• DOI: 10.1016/j.biortech.2024.131620

[Display omitted] •Red light increased lysine and protein accumulation in C. pyrenoidosa.•Red light enhanced lysine production via Ca2+-CaM/PCK/PEPC pathway.•Red light-driven pathways efficiently upregulated lysine-related gene expression.•C. pyrenoidosa showed great nutritional valueas a protein feed under red light. Microalgae are emerging as a novel single-cell protein source that can substitute traditional plant protein feeds. In this investigation, lysine and protein accumulation in Chlorella pyrenoidosa were significantly enhanced under red light-emitting diode light, addressing challenge of limiting amino acid in plant proteins. The study employed targeted metabolomics, HPLC, and qRT-PCR to validate the light-induced pathway triggering lysine biosynthesis. Specifically, the pathway involves Ca2+-CaM as an intermediary in signal transduction, which directly inhibits PEPC activity. This inhibition directs a significant carbon flux towards central carbon metabolism, resulting in increased pyruvate levels—a critical precursor for lysine biosynthesis via the diaminopimelate pathway. Ultimately, the content of protein and lysine under red light increased by 36.02 % and 99.56 %, respectively, compared to those under white light. These findings provide a novel orientation for the precise regulation of lysine accumulation in microalgae, and moreover lay a solid theoretical foundation for producing microalgal proteins.