(401bd) Recovery of Lactic Acid from the Pretreated Fermentation Broth Based on a Novel Hyper-Cross-Linked Meso-Micropore Resin

Lactic acid (2-hydroxypropionic acid) is one of the most important organic chiral compound, containing both the hydroxyl and carboxylic acid groups, which is widely used in food, pharmaceutical, chemicals, cosmetics and other industries. Recently, as a monomer for the synthesis of polylactic acid, the demand of lactic acid has a significant increasing. Production of lactic acid by fermentation is the main production method in industry, because the fermentation can make full use of cheap biomass resources, and can produce one of the two stereoisomers of lactic acid or racemic mixture with high yield and productivity. However, the separation of high purity lactic acid from fermentation broth has been a difficult and hot spot.

In this work, an innovative benign process for recovery lactic acid from its fermentation broth is proposed using a novel hyper-cross-linked meso-micropore resin. No environmentally harmful wastes are produced in this process, since deionized water (eluent) is the only substance added to the separation process. This work focuses on modeling the competitive adsorption behaviors of glucose, lactic acid and acetic acid ternary mixture and explosion of the adsorption mechanism. The characterization results showed the resin had a large BET surface area and specific pore structure with hydrophobic properties. By analysis of the physicochemical properties of the solutes and the resin, the mechanism of the separation is proposed as hydrophobic effect and size exclusion. Subsequently three chromatographic models, i.e., GR (General Rate Model), TDM (Transport Dispersive Model) and LDF (Linear Driving Force) models were applied to predict the competitive breakthrough curves of the ternary mixture under different operating conditions. The pore diffusion was the major limiting factor for the adsorption process, which was consistent with the BET results. In the end of this work, the selected model (TDM) was validated by comparison of the chromatographic peaks of the ternary-mixture with pretreated real fermentation broth used as a feed solution. According to this work and comparison with other literature, the novel HD-06 resin can be a good potential adsorbent for the future SMB continuous separation process.