Resumo

QUINTERO, Joan et al. Purification of lactic acid obtained from a fermentative process of cassava syrup using ion exchange resins. Rev.fac.ing.univ. Antioquia [online]. 2012, n.65, pp.139-151. ISSN 0120-6230.

In this work, the fermentative lactic acid (LA) production and its further separation by ionic exchange resins was evaluated. A Lactobacillus brevis strain was used to perform lab scale experiments under anaerobic conditions, using a low nutritional content media with cassava flour as carbon source (HY1). For a fermentation time of 120h in a 7.5-L bioreactor, the LA concentration was 24.3±0.07g LA/L and productivity 0.20 g/L/h, at pH 6.5 and 38°C. For LA recovery, the Amberlite IRA-400 and IR-120 exchange resins were used. First of all, a LA isothermal adsorption on Amberlite IRA-400, Cl^-, OH^- and HS0₄^2- activated form, was performed at 25°C. The Cl^- activated resin was tested at pH 5, whereas the OH^- activated form was tested at pH 3.5 and 6.3. The highest adsórbate content was 0.59±0.03 g LA/g resin at pH 6.3 when the resin was OH^- activated. Following, the breakthrough curves were carried out in an Amberlite IRA-400 packed column at pH 3 and 5, and 0.5 and lmL/min; the maximum LA loaded was 0.109±0.005 g AL/g resin at pH 3 and 0.5 mL/min. Finally, the LA recovery was assessed in a system of series of columns packed with Amberlite IRA-400 e IR-120; the LA recovery was 77% and 73%, when the system was set at 0.5mL/min, 25°C, and a feeding at pH 3 and 5, respectively, into the packed columns.

Palavras-chave : Lactic acid; Lactobacillus brevis; ionic exchange resins; adsorption isotherms.

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