Sustainable Triacetic Acid Lactone Production from Sugarcane by Fermentation and Crystallization

Abstract

There is a pressing need to replace crude oil with renewable feedstocks such as sugarcane to manufacture fuels and chemicals. Triacetic acid lactone (TAL) is a bioproduct of particular interest as a platform chemical with the potential to produce commercially important chemicals including sorbic acid and polydiketoenamine plastics. In this study, we leveraged BioSTEAM−an open-source platform−to design, simulate, and evaluate under uncertainty (via techno-economic analysis, TEA, and life cycle assessment, LCA) biorefineries producing TAL from sugarcane by microbial conversion of sugars. We experimentally characterized TAL solubility, calibrated solubility models, and designed a process to separate TAL from fermentation broths by crystallization. The biorefinery could produce TAL (≥94.0 dry-wt%) at a minimum product selling price (MPSP) of $4.87·kg-1 (baseline) with a range of $4.03−6.08·kg-1 (5th−95th percentiles). The MPSP was below the maximum viable TAL price range for sorbic acid production ($5.99−7.74·kg-1) in ≥93% of simulations and consistently below the benchmark price to produce polydiketoenamines ($10·kg-1). We used a quantitative sustainable design framework to explore the theoretical fermentation space (titer, yield, and productivity combinations), potential separation improvements (mitigating TAL ring-opening decarboxylation through pH control), and operation scheduling and capacity expansion strategies (e.g., through integrated sweet sorghum processing). Advancements in key design and technological parameters could greatly improve the biorefinery’s financial viability (MPSP of $2.60·kg-1 [$2.31−3.16·kg-1], consistently below the maximum viable price range for sorbic acid and polydiketoenamines production) and environmental benefits (carbon intensity of 3.65 [1.90−5.43] kg CO2-eq·kg-1, with net displacement of fossil energy consumption in 70% of simulations). This research highlights the ability of agile TEA-LCA to screen promising designs, navigate sustainability tradeoffs, prioritize research needs, and chart quantitative roadmaps for the continued development of bioproducts and biofuels.