Estimating the microbial lipid synthesis and environmental impacts of Yarrowia lipolytica under four cultivation modes

Increasing attention has been directed toward enhancing microbial lipid yield through utilizing high-concentration VFAs, which can be economically obtained from organic waste fermentation, serving as promising carbon sources for oleaginous yeasts. It's crucial to design cultivation strategies that effectively address acid inhibition and improve lipid production. This study employed four cultivation strategies: single-stage batch cultivation, two-stage batch cultivation, continuous cultivation, and continuous cell recycling cultivation, utilizing 30 g/L acetic acid as the carbon source. Continuous cell recycling cultivation achieved a lipid yield of 4.3 g/L and a DCW of 12.30 g/L, representing a sixfold and fivefold increase, respectively, compared to batch cultivation. Life cycle assessment revealed that two-stage cultivation had the most significant negative environmental impact, while continuous cell recycling cultivation exhibited only one-fifth of the global warming potential and reduced greenhouse gas emissions by approximately 1300 kg·CO2eq/t relative to petrochemical diesel, thereby offering substantial environmental benefits. This is attributed to the fact that continuous cell recycling cultivation can efficiently utilize carbon sources, thereby minimizing waste generation and the demand for new raw materials. The continuous cell recycling cultivation shows great potential for industrial-scale applications, however, further research is needed to fully optimize the process and evaluate the economic feasibility.