Harnessing yeasts for sustainable succinic acid production: advances in metabolic engineering and biorefinery integration

Abstract

This review highlights the potential of Yarrowia lipolytica and other yeasts as sustainable producers of bio-based succinic acid (SA), a key platform chemical with applications in bioplastics, solvents, and pharmaceuticals. Recent advances in metabolic engineering have substantially improved SA titers, yields, and productivities in yeasts. These improvements were achieved by reconstructing biosynthetic pathways, disrupting gene involved in side-metabolism and/or expressing heterologous genes involved in critical metabolic functions. The use of renewable feedstocks, including crude glycerol, agricultural residues, food waste hydrolysates, and industrial by-products, has shown promise in reducing both production costs and environmental impacts. Innovative downstream separation techniques, such as in situ extraction, membrane filtration, and crystallization, further contribute to process sustainability. Integrating yeast-based SA production into circular biorefineries and adopting continuous production systems are promising strategies for enhancing economic feasibility and minimizing ecological footprints. Although challenges related to scale-up and process integration persist, ongoing advancements in genetic engineering and bioprocessing technologies position yeast-based processes as a viable route for sustainable, large-scale bio-based SA production within a circular bioeconomy framework.

Keywords: biorefineries; life cycle assessment; metabolic engineering; succinic acid; technoeconomic evaluation; yeast.

Figure 1.

Metabolic pathways for carbon assimilation and SA biosynthesis in yeasts. Oxidative TCA cycle (blue arrows); (2) reductive TCA cycle (purple arrows, partly shown); (3) glyoxylate cycle (red arrows). Ach, acetyl-CoA hydrolase; Acs, acetyl-CoA synthase; Acon, aconitase; Adh, alcohol dehydrogenases; Ald, aldehyde dehydrogenase; α-KG, a-ketoglutarate; Cs, citrate synthase; DHAP, dihydroxyacetone phosphate; DHA, dihydroxyacetone; Dak, dihydroxyacetone kinase; Fum, fumarase; Frd, fumarate reductase; GAP, glyceraldehyde 3-phosphate; Gpd, glycerol-3-phosphate dehydrogenase; Gdh, glycerol dehydrogenase; Gk, glycerol kinase; Hxk1, hexokinase 1; Icl, isocitrate lyase; Idh, isocitrate dehydrogenase; Kgdh, α-ketoglutarate dehydrogenase; Mdh, malate dehydrogenase; Mae, dicarboxylic acid transporter; Mls, malate synthase; Pdc, pyruvate decarboxylase; Pyc, pyruvate carboxylase; Pck, phosphoenolpyruvate carboxykinase; Pdh, pyruvate dehydrogenase; Pyk, pyruvate kinase; PEP, phosphoenolpyruvate; Scs, succinyl‐CoA synthase; Sdh, succinate dehydrogenase; Xr, xylose reductase; Xdh, xylitol dehydrogenase; Xk, xylulose kinase; Yhm2, mitochondrial citrate transporter; Yht, hexose transporter.

Figure 2.

Strategies for succinic acid separation and purification.

Figure 3.

Biorefinery concept for SA production (Modified from Efthymiou et al. 2021).

Figure 4.

Biorefinery approach for in-situ production and extraction of SA by Y. lipolytica (Modified form Ioannidou et al. , Stylianou et al. 2023).

Figure 5.

Global warming potential (GWP) and abiotic depletion (ADP) values for different SA production processes using fossil and renewable resources. Case 1. Fossil-based SA (Cok et al. 2014); Case 2. Anaerobic bacterial culture to succinate salt at pH 7 with SA purification via an electrodialysis-based DSP process (EU electricity production grid) (Cok et al. 2014); Case 3. Anaerobic bacterial culture to succinate salt at pH 7 with SA purification via an electrodialysis-based DSP process (France electricity production grid) (Cok et al. 2014); Case 4. Low pH yeast fermentation with direct crystallization-based SA purification (France electricity production grid) (Cok et al. 2014); Case 5. Yeast fermentation at pH 6 with in-situ production and exctraction using a electrochemical membrane bioreactor (100% renewable electricity) (Ioannidou et al. 2023b); Case 6. Bacterial fermentation with NH₃ and salt separation with continuous ion exchange columns. Ammonium phosphate is produced as a co-product fertilizer (Moussa et al. 2016).