Direct microbial production of 1,2-propanediol in a sugarcane biorefinery: Financial and environmental benefits from technology development

Abstract

1,2-propanediol (1,2-PDO) is a widely used chemical with various industrial applications. Indirect biobased methods provide a sustainable alternative to petrochemical processes but are hindered by the energy-intensive and complex conversion processes. Direct biobased 1,2-PDO methods could overcome these challenges but require additional strain and bioprocess improvements. The present study quantified the technical performances required to achieve desirable financial and environmental outcomes for direct biobased 1,2-PDO compared to the fossil-based alternative. The direct biobased production of 1,2-PDO in an integrated sugarcane biorefinery was simulated using Aspen Plus® software. Two downstream processing options, reactive distillation (S1-PDO-RD) and liquid-liquid extraction (LLE) (S2-PDO-LLE), were evaluated to address process energy inefficiencies through techno-economic and environmental assessments. S2-PDO-LLE had an 8.7 % lower MSP with 2.2 % more GHG emissions than S1-PDO-RD at current bioconversion capacity, but neither scenario was economically viable. With improved bioconversion efficiencies, S2-PDO-LLE could achieve an MSP that is 19.9 % lower than the fossil-based 1,2-PDO price with 48.5 % fewer GHG emissions than the commercial method. Similarly, S1-PDO-RD could narrowly outperform the fossil-based method with 10.7 % lower GHG emissions. The factorial analysis indicated that LLE amplifies the viability gains achievable through improved strain and bioprocess performances and should be prioritized for 1,2-PDO downstream processing. Direct biobased methods have high potential to outperform incumbent petrochemical methods due to better energy efficiency and reduced reliance on yield-specific chemicals.