Mixotrophic culture of Chaetoceros sp and the synergistic carbon and energy metabolism

: Shan Shengzhou, Wang Shanshan, Yan Xi, Chen Kang, Liang Li, Li Xiaohui, Zhou Chengxu, Yan Xiaojun, Ruan Roger, Cheng Pengfei

Publisher: Elsevier BV

: 2023

: Bioresource Technology

: Bioresource technology

: Bioresour Technol

: 129912

: 390

: 0960-8524

: 1873-2976

DOI: https://doi.org/10.1016/j.biortech.2023.129912(external)

: https://doi.org/10.1016/j.biortech.2023.129912(external)

This research studied the metabolic mechanism of the mixotrophic Chaetoceros sp. The results showed this alga had the highest cell density and growth rate of 47.72 × 10⁵ cells mL^-1 and 0.41 d^-1, respectively, with a maximum dry weight of 2.90 g/L, when compared to photoautotrophic and photoheterotrophic modes. Compared to photoheterotrophy, transcriptomics results showed the Rubisco, PGK, and GAPDH related genes were separately up-regulated by 1.03, 2.36, and 1.36 times in CBB cycle in mixotrophic mode, suggesting intermediate metabolites of EMP and PPP can enter the chloroplast via transporter proteins, or membrane permeation, and feedback inhibition regulates the reduction of multiple reactions in CBB cycle. Chaetoceros sp. achieves high biomass by utilizing ATP and carbon structures from EMP and PPP pathways, and the addition of NaHCO₃ leads to an up-regulation of CBB cycle for the mixotrophic alga, resulting in higher biomass compared to the photoheterotrophic mode.