Purification of Lactic Acid from Fermentation Broths by Ion-Exchange Resins

Abstract

In this work, a novel process for lactic acid purification based on ion exchange is proposed. It consists of two stages: first, a strong cation resin was used to reduce the broth pH below the pK a of lactic acid (3.86) and remove the cations present in the solution; then lactic acid was separated from the other anions in the broth using a weak anion exchanger. The ion exchangers selected were Lewatit S2568H and Lewatit S3428 (Bayer, Germany). The Lewatit S2568H resin retained the cations in the broth with an apparent capacity of 1.7 equiv/ L, reducing the broth pH below 3.86. It was able to decrease the pH of the broth to as low as 1.5, generating 4 bed volumes (BV) of acidified and partial demineralized broth. In the second step, the acidified broth was purified by the Lewatit S3428 resin, which retained the other anions present in the broth, producing an aqueous solution of lactic acid. This resin was able to produce 25 BV of purified lactic acid with selectivity higher than 99.9%. The final purity of lactic acid was higher than 99%.

Biochemical Production and Separation of Carboxylic Acids for Biorefinery Applications

“…Ion exchange resins are usually polymeric resins with a linked cation or anion exchange group [148]. For carboxylic acid separation, predominantly used resins are strong or weak base resins, which have tertiary or quaternary amines as the ion exchange group [149,150]. The carboxylic acids are usually recovered from the ion exchange resin through caustic elution and can be concentrated through evaporation and hydrolyzed to give a pure acid for further processing.…”

Effect of operating parameters on precipitation for recovery of lactic acid from calcium lactate fermentation broth

“…It is related to the pKa value of calcium lactate (3.86). When the pH of a calcium lactate solution is lower than its pKa value, some of the calcium lactate exists in an undissociated (unionized) form, making reaction with sulfuric acid difficult, whereas when the pH is greater than the pKa, calcium lactate exists in dissociated (ionized) form and reacts easily with sulfuric acid, thus producing calcium sulfate more efficiently [17]. The amount of calcium sulfate produced from reactions between calcium lactate and sulfuric acid at these different pHs is indicated in Fig.…”

Purification of surfactin in pretreated fermentation broths by adsorptive removal of impurities

“…1 shows the effect of equilibrium pH (pH eq ) on the amount of equilibrium exchange (q e ) using AG1-X4 resin at various initial surfactin concentration (C 0 = 1000-4000 mg/L). Two unusual results are observed in contrast to common amino acid systems [16][17][18][19][20][21][22]. One is that the higher amount of surfactin exchanged is obtained at two extremes of the pH range studied (6 and 11) when C 0 is not lower than 1000 mg/L, instead of continuous increase or decrease of q e with pH.…”

“…A multi-step strategy, using a sequence of concentration and purification steps, is more effective and satisfactory [13]. Ion-exchange resins are nowadays commonly used in the recovery and purification of carboxylic acids, amino acids, and peptides on a large-scale [16][17][18]. Besides that, neutral polymeric resins become available for the recovery of amino acids, antibiotics, limonoids, and flavonoids [18][19][20][21][22].…”