Dewatering fermentation broth for keto carboxylic acid enrichment by forward osmosis: A techno-economic analysis

This study demonstrated the importance of fermentation broth pretreatment and dewatering by forward osmosis (FO) before keto carboxylic acid recovery. The most effective and profitable pretreatment procedure was a combination of centrifugation, ceramic ultrafiltration of molecular weight cut-off of 15 kDa, and ceramic nanofiltration of molecular weight cut-off of 450 Da. By applying the complex pretreatment and FO as a pre-concentration step of fermentation broth dewatering, the keto acid enrichment of two times was achieved for alpha-ketoglutaric acid and pyruvic acid. Extensive fouling analysis performed in this study confirmed that the proposed pretreatment procedure was sufficient to avoid severe fouling of the FO dewatering process. A techno-economic analysis of the proposed keto acid extraction scheme shown that by using FO for fermentation broth dewatering, the total capital investment was reduced and the payback time was shortened by 0.83 yr.