Process design and carbon footprint analysis of thraustochytrid biomass production using distillery wastewater

Abstract

An increasing global demand for omega-3 polyunsaturated fatty acids (PUFAs) necessitates the development of sustainable alternatives to traditional fish oil. Thraustochytrids, a group of marine protists, have emerged as a promising microbial source capable of producing high levels of PUFAs. However, the commercial viability of producing PUFA-rich thraustochytrid biomass often is hindered by high media costs. This study explores a sustainable process design using distillery wastewater (DWW) as a low-cost feedstock. A commercial-scale process of the thraustochytrid biomass (TB) production is simulated in DWSIM (a steady-state and dynamic sequential modular chemical process simulator) to establish a validated flowsheet. Mathematical validation is done by calculating the percentage error between the DWSIM simulation and the empirical bench-scale cell dry weight data. Based on the model’s material and energy balances, a comprehensive carbon footprint analysis is conducted to evaluate the environmental sustainability of the system. Analysis identified carbon footprint hotspots from electricity consumption, specifically for the freeze-dryer unit. Alternatives include replacement of the unit to a homogenizer for cell disruption, reducing the footprint to 4.16%, still below the desired 7.5% reduction target. Therefore, more emissions reduction options such as shifting to renewable energy should be explored. This DWSIM-based commercial-scale analysis addresses a critical knowledge gap in microbial PUFA production by quantifying unit operation resource intensities, identifying key environmental hotspots, and providing footprint-reduction strategies essential for translating thraustochytrid cultivation from laboratory to industrial scale.

Keywords

Thraustochytrid / distillery wastewater / DWSIM / carbon footprint intensity analysis

References

[1] Oliver L,Marañón I,Barrio RJ.Producing omega-3 polyunsaturated fatty acids: a review of sustainable sources and future trends for the EPA and DHA market.Resources2020;9:148

[2] Du F,Xu YS.Biotechnological production of lipid and terpenoid from thraustochytrids.Biotechnol Adv2021;48:107725

[3] Patel AK,Kumar P.Emerging prospects of microbial production of omega fatty acids: recent updates.Bioresour Technol2022;360:127534

[4] Morabito C,Maës C.The lipid metabolism in thraustochytrids.Prog Lipid Res2019;76:101007

[5] Raghukumar S.Thraustochytrid marine protists: production of PUFAs and other emerging technologies.Mar Biotechnol2008;10:631-40

[6] Aasen IM,Heggeset TM.Thraustochytrids as production organisms for docosahexaenoic acid (DHA), squalene, and carotenoids.Appl Microbiol Biotechnol2016;100:4309-21

[7] Athenaki M,Diamantopoulou P.Lipids from yeasts and fungi: physiology, production and analytical considerations.J Appl Microbiol2018;124:336-67

[8] Kothri M,Elazzazy AM,Moussa TAA.Microbial sources of polyunsaturated fatty acids (PUFAs) and the prospect of organic residues and wastes as growth media for PUFA-producing microorganisms.FEMS Microbiol Lett2020;367:fnaa028

[9] Pleissner D.Valorisation of food waste in biotechnological processes.Sustain chem Process2013;1:20

[10] Krishnamoorthy S,Vijayasekaran M.Characterization of distillery wastewater - An approach to retrofit existing effluent treatment plant operation with phycoremediation.J Clean Prod2017;148:735-50

[11] Kasprzak J. Development of process configurations and simulation of biobutanol production using DWSIM. Master’s Thesis, Royal Military College of Canada, Kingston, ON, 2024. https://espace.rmc.ca/jspui/handle/11264/1903 (accessed 2026-01-25).

[12] Moliner C,Curti M.Simulation and experimental validation of biomass gasification in a spouted bed reactor: troubleshooting using dwsim.Syst Control Trans2025;4:271-5

[13] Jacquemin L,Sablayrolles C.Life cycle assessment (LCA) applied to the process industry: a review.Int J Life Cycle Assess2012;17:1028-41

[14] Mckuin BL,Sarker PK.Comparative life cycle assessment of heterotrophic microalgae Schizochytrium and fish oil in sustainable aquaculture feeds.Elem Sci Anthr2022;10:00098

[15] Lee Chang KJ,Dunstan GA.Life cycle assessment: heterotrophic cultivation of thraustochytrids for biodiesel production.J Appl Phycol2015;27:639-47

[16] Tjan W,Foo DC.A graphical representation of carbon footprint reduction for chemical processes.J Clean Prod2010;18:848-56

[17] dos Reis GA,Martínez-Burgos WJ.Sustainable omega-3 lipid production from agro-industrial by-products using thraustochytrids: enabling process development, optimization, and scale-up.Foods2024;13:3646 PMCID:PMC11593561

[18] Mobius^® iFlex Bioreactor. Data sheet. MilliporeSigma. https://www.merckmillipore.com/deepweb/assets/sigmaaldrich/marketing/global/documents/417/331/ds12340en-mobius-iflex-bioreactor-datasheet-ms.pdf (accessed 2026-01-25).

[19] Sen B,Lu L,He Y.Elemental composition and cell mass quantification of cultured thraustochytrids unveil their large contribution to marine carbon pool.Mar Drugs2021;19:493 PMCID:PMC8468426

[20] Roels JA.Application of macroscopic principles to microbial metabolism.Biotechnol Bioeng1980;22:2457-514

[21] Sreemahadevan S,Palanisamy M.Evaluation of the open source process simulator DWSIM for bioprocess simulation.Period Polytech Chem Eng2024;68:195-202

[22] Disconzi FP.Modeling, simulation, and optimization of the centrifugal separation of a microalgae-culture medium mixture.Biomass Bioenergy2020;143:105871

[23] Calculation tools and guidance. Greenhouse gas protocol. https://ghgprotocol.org/calculation-tools-and-guidance (accessed 2026-01-25).

[24] Philippines country climate development report. The World Bank Group. https://thedocs.worldbank.org/en/doc/4ec3282919652f7545bc25c49c1811e4-0070012022/original/PHCCDR-FINAL-formatted.pdf (accessed 2026-01-25).

[25] Li X,Liu Q,Wang Q.Lipid production of schizochytrium sp. HBW10 Isolated from coastal waters of northern China cultivated in food waste hydrolysate.Microorganisms2023;11:2714 PMCID:PMC10672807

[26] Cruz PS. Aquaculture feed and fertilizer resource atlas of the philippines. FAO Fisheries Technical Paper, vol. M-44; Food and Agriculture Organization of the United Nations, 1997. https://www.fao.org/4/w6928e/w6928e00.htm (accessed 2026-01-25).

[27] He Y,Ning Y,Sen B.Saturated and polyunsaturated fatty acids production by aurantiochytrium limacinum PKU#Mn4 on enteromorpha hydrolysate.Mar Drugs2023;21:198 PMCID:PMC10143273

[28] ClimateHub. Explore Climate Footprints. https://apps.carboncloud.com/climatehub/ (accessed 2026-01-25).

[29] Shimizu Y,Toyosada K.The CO₂ emission factor of water in Japan.Water2012;4:759-69

[30] Emission factors for greenhouse gas inventories. U.S. Environmental Protection Agency. https://www.epa.gov/system/files/documents/2024-02/ghg-emission-factors-hub-2024.pdf (accessed 2026-01-25).

[31] Philippines, country profile 2020. Climate transparency. https://www.climate-transparency.org/wp-content/uploads/2021/01/Philippines-CT-2020.pdf (accessed 2026-01-25).

[32] Corrêa PS,Martins AA,Mata TM.Microalgae biomolecules: extraction, separation and purification methods.Processes2021;9:10

[33] Kwak M,Hong WK,Chang YK.Simultaneous cell disruption and lipid extraction of wet aurantiochytrium sp. KRS101 using a high shear mixer.Bioprocess Biosyst Eng2018;41:671-8