Systematic metabolic tools reveal underlying mechanism of product biosynthesis in Chromochloris zofingiensis

This study comprehensively explored underlying mechanism of fed-batch culture on product biosynthesis in Chromochloris zofingiensis by dynamic model, targeted metabolite determination, enzyme activity analysis, and 13C tracer-based metabolic flux analysis. Based on dynamic models of cell growth and product formation, exponential fed-batch culture and fed-batch culture based on pH changes were established to increase biomass concentration by 20.05-fold and 18.28-fold, respectively. Exponential fed-batch culture exhibited great potentials in biodiesel and protein productions from microalgae. Systematic metabolic tools revealed fed-batch culture limited photosynthetic efficiency by inhibiting photosystem and Rubisco activity, while strengthened respiratory action to provide more substances and energy for product biosynthesis. Fed-batch culture elevated biosynthetic capability for carotenoid and lipid by promoting related metabolic flux and contents of pyruvate and ace-CoA. Finally, economic analysis revealed biomass cost was decreased to 1.99 $/kg from 2.39 $/kg, suggesting fedbatch culture was a cost-effective strategy to improve economic viability of microalgal production.

Automated summary

This study investigated the mechanism of fed-batch culture on product biosynthesis in Chromochloris zofingiensis through dynamic modeling, metabolite determination, enzyme activity analysis, and metabolic flux analysis. Results showed that fed-batch culture significantly increased biomass concentration, biodiesel, and protein production potentials while promoting carotenoid and lipid biosynthesis. Economic analysis indicated that fed-batch culture reduced biomass costs, making it a cost-effective strategy for improving the economic viability of microalgal production.