Resumo

ARIAS ZABALA, MARIO; HENAO NAVARRETE, LINA  e  CASTRILLON GUTIERREZ, YULIETH. LACTIC ACID PRODUCTION BY FERMENTATION OF COFFEE MUCILAGE WITH LACTOBACILLUS BULGARICUS NRRL-B548. Dyna rev.fac.nac.minas [online]. 2009, vol.76, n.158, pp.147-153. ISSN 0012-7353.

It was studied the lactic acid (LA) production by simultaneous hydrolysis and fermentation of coffee mucilage with Lactobacillus bulgaricus NRRL-B548 in 500 ml vessels with 400 ml of medium, stirred at 110 rpm. The pH of medium was manually controlled between 5.6 and 6.0 by addition of NaOH 5M each 2 hours. Temperature was maintained at 45^oC. The inoculum volume was 10% of the work volume. In order to optimize the LA productivity (P) three values of inoculum concentration (5, 10 and 15 g/l) and three initial concentrations of total reduction sugars (TRS) (27, 35 and 60 g/l) were tested. The maximal final concentration of LA was 41 g/l, obtained with an inoculum of 10 g/l and initial concentration of TRS of 60 g/l. The maximal productivity was 1.44 g/l-h, after 25 hours of fermentation, and it was obtained with an inoculum of 10 g/l and initial concentration of TRS of 60 g/l. At these same conditions it was obtained the maximal productivity at the end of the process (30 h) of 1.39 g/l-h. The maximal yield coefficient (Y_PS), calculated at 30 h of fermentation, was 1.67 g/g, corresponding to an inoculum of 15 g/l and initial concentration of TRS of 60 g/l.

Palavras-chave : Lactic acid; mucilage; fermentation; Lactobacillus bulgaricus.

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