Economic Process Evaluation and Environmental Life-Cycle Assessment of Bio-Aromatics Production

Abstract

The bio-based production of aromatics is experiencing a renaissance with systems and synthetic biology approaches promising to deliver bio-catalysts that will reach yields, rates, and titers comparable to already existing bulk bio-processes for the production of amino acids for instance. However, aromatic building blocks derived from petrochemical routes have a huge economic advantage, they are cheap, and very cheap in fact. In this article, we are trying to shed light on an important aspect of biocatalyst development that is frequently overlooked when working on strain development: economic and environmental impact of the production process. We estimate the production cost and environmental impact of a microbial fermentation process depending on culture pH, carbon source and process scale. As a model molecule we use para-hydroxybenzoic acid (pHBA), but the results are readily transferrable to other shikimate derived aromatics with similar carbon yields and production rates.

Keywords: aromatics; fermentation; life-cycle assessment; pHBA; process development.

FIGURE 1

Simplified bacterial bioprocess where pH regulation is included (note that aeration is not detailed). The first part of the process contains the cultivation phase, where the biomass is produced in consecutive three seed reactors and then the fermentation is done. The second part presents the DSP with filtrations, crystallization, and centrifugation and drying. In the DSP of the yeast-based alternative no microfiltration is made.

FIGURE 2

Overall ranking of the different scenarios based on their economic and environmental impacts.

FIGURE 3

Contribution of different impact factors to the total impact of the different scenarios.

FIGURE 4

Global warming potential of the different scenarios given in kg CO₂-equivalent per kg pHBA produced.