Biomanufacturing of value‐added products from oils or fats: A case study on cellular and fermentation engineering of Yarrowia lipolytica

Abstract

The United States produces more than 10 million tons of waste oils and fats each year. This paper aims to establish a new biomanufacturing platform that converts waste oils or fats into a series of value‐added products. Our research employs the oleaginous yeast Yarrowia lipolytica as a case study for citric acid (CA) production from waste oils. First, we conducted the computational fluid dynamics (CFD) simulation of the bioreactor system and identified that the extracellular mixing and mass transfer is the first limiting factor of an oil fermentation process due to the insolubility of oil in water. Based on the CFD simulation results, the bioreactor design and operating conditions were optimized and successfully enhanced oil uptake and bioconversion in fed‐batch fermentation experiments. After that, we investigated the impacts of cell morphology on oil uptake, intracellular lipid accumulation, and CA formation by overexpressing and deleting the MHY1 gene in the wild type Y. lipolytica ATCC20362. Fairly good linear correlations (R2 > 0.82) were achieved between cell morphology and productivities of biomass, lipid, and CA. Finally, fermentation kinetics with both glucose and oil substrates were compared and the oil fermentation process was carefully evaluated. Our study suggests that waste oils or fats can be economical feedstocks for biomanufacturing of many high‐value products.

CFD evaluation of hydrophobic feedstock bench‐scale fermenters for efficient high agitation volumetric mass transfer

“…[ 48 ] These trends correlate with improved Y. lipolytica fermentation with oil substrate under these conditions. [ 5 ] Overestimation of k L a by the single bubble size was demonstrated previously [ 26 ] and is accounted for with C k . The single bubble size used for the air phase does not account for bubble‐bubble interactions and bubble turbulence as captured by the population balance equations, impacting multiple parameters.…”

“…CFD simulations were based on previous Y. lipolytica fed-batch fermentations with vegetable oil in the medium in a 1-L working volume glass bioreactor (Sartorius Stedim UniVessel) with key geometrical details displayed in Figure 1B,C. [5]…”

“…[12] The smaller particles and improved mixing of the oil and water with the PBI setup at 1200-RPM stirring speed have been correlated to improved Y. lipolytica fermentation for bioconversion of TAG oil into specific high-value products and closely match the improved experimental production. [5] However, two-phase oil and water simulations make simplifications, mostly the omittance of air, the impact of which will be reviewed in Section 3. which model extensions [33] have highly enhanced turbulent vegetable oil-in-water emulsion CFD predictions. [34] In addition, the widely used Schiller and Naumann drag correlation only considers spherical particles and cannot correctly represent interface deformability force changes.…”

“…[1] This makes Y. lipolytica an ideal choice for efficient bioconversion of oils/fats into high-value pharmaceuticals and food additives such as citric acid and wax esters. [2][3][4][5] This strictly aerobic yeast requires efficient oxygen transfer for cell growth and lipid production, [6] and oil substrates must be well-dispersed in the aqueous medium with high agitation for small oil droplets to attach to Abbreviations: BC, Boundary condition; k L a, Volumetric mass transfer coefficient; MUSIG, Multiple size group; PBM, Population balance modeling; TSF, Timescale factor; vvm, Gas sparging rate (volume/min) per unit volume of unaerated liquid.…”

Concept of Batch and Fed-Batch Cultures of Yarrowia lipolytica as a Valuable Source of Sterols with Simultaneous Valorization of Molasses and Post-Frying Rapeseed Oil

“…Biotechnological valorization of agri-food industry waste is closely related to sustainable resource reuse technologies. Food side-streams could be potentially transformed into added value products by biotechnological processes based on non-conventional microorganisms, such as Yarrowia lipolytica yeast [4][5][6][7]. The physiological characteristics of Appl.…”