Ectoine production from biogas: A sensitivity analysis. Effect of local commodity prices, economy of scale, market trends and biotechnological limitations

Abstract

The utilization of methanotrophic haloalkaliphilic bacteria for the production of ectoine in waste treatment plants has demonstrated a great potential to upgrade the traditional use of biogas as energy vector and the current industrial routes for the production of this high added-value chemical (600–1000 €·kg−1). However, the influence of socio-economic aspects such as the location of the plant, the economy of scale and the market fluctuations on the profitability of the process remains unknown. A techno-economic and sensitivity analysis of the bioconversion of CH4 into ectoine in a bubble column bioreactor and the extraction and purification of ectoine via ionic exchange chromatography was herein conducted using Madrid as base-case scenario. The geographical assessment performed in 13 representative cities revealed high differences in the ectoine production costs, ranging from 158 to 231 €·kg−1. The economy of scale analysis evidenced a high dependence of the ectoine production costs towards the production scale, amounting to 782 and 164 €·kg−1 when manufacturing 0.1 and 89.6 t ectoine·y−1, respectively. The techno-economic study also showed a high robustness of CH4-ectoine profitability towards future market fluctuations, with all the scenarios analyzed guaranteeing internal rates of return >15% and payback periods <10 y. Finally, the sensitivity analysis identified the improvement of CH4 elimination capacity in bioreactors, the development of highly efficient microbial strains and the selection of the highest quality ionic exchange resins as key factors impacting the profitability of future biogas-to-ectoine biorefineries.