A novel fed-batch strategy enhances lipid and astaxanthin productivity without compromising biomass of Chromochloris zofingiensis

• Published in: Bioresource technology Vol. 308; p. 123306
• Main Authors: Sun, Han, Ren, Yuanyuan, Lao, Yongmin, Li, Xiaojie, Chen, Feng
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.07.2020
• Subjects: adenosine triphosphate; Astaxanthin; biochemical pathways; Biomass; biomass production; biosynthesis; carbon; Carbon availability; Carbon conversion; carbon metabolism; Fatty acid metabolism; Fed-batch culture; lipid content; Lipids; metabolic flux analysis; metabolites; NADP (coenzyme); Nitrogen; Xanthophylls; Carbon conversion; Fatty acid metabolism; Carbon availability; Fed-batch culture; Astaxanthin
• ISSN: 0960-8524; 1873-2976; 1873-2976
• DOI: 10.1016/j.biortech.2020.123306

[Display omitted] •Fed-batch strategy increased 41.5% lipid productivity without compromising biomass.•Carbon dependent kinetics under stress conferred cells with a higher biomass.•Central carbon metabolism offered energy and carbon availability for lipid synthesis.•Sufficient precursor and active synthetic pathway promoted lipid content.•Fed-batch strategy was attractive by understanding lipid metabolism in detail. To improve lipid and astaxanthin productivity without compromising biomass during the whole cultivation period, carbon-dependent kinetics involving nitrogen stress was applied under excess light to elevate intracellular carbon availability and metabolic activity of Chromochloris zofingiensis. Results suggested that fed-batch strategy proposed could increase lipid and astaxanthin productivity to 457.1 and 2.0 mg L−1 d−1, respectively. Biomass productivity at 1084.3 mg L−1 d−1 was comparable with that under suitable condition. Then 13C tracer-based metabolic flux analysis (13C-MFA) demonstrated that central carbon metabolism provided ATP, NADPH and carbon availability for lipid biosynthesis during the strategy. In combination with targeted metabolite analysis, 13C-MFA revealed that the strategy improved precursor content for lipid biosynthesis and elevated path rate to synthesize C16:0 and C18:0. The enhanced lipid content potentially accounted for the high biomass productivity. Therefore, comprehensively understanding relationships between carbon availability and carbon conversion could precisely design strategy for productivity improvements during cultivation.