2.3. Recovery of LA
The recovery of LA from the large scale fermentation broth was
conducted according to Lin et al. (2010) with slight modification.
The fermentation broth was centrifuged (7000 rpm for 1 h) and
the supernatant was filtered through glass fiber paper (Whatman
GFA) to separate the solid residue. The brown filtrate was mixed
with 5% activated carbon (Aldrich) for 2 h to remove protein, color,
and cell debris, and the mixture was again clarified by centrifugation
and filtration as described above. The solution was then
passed through an ion-exchange resin column (Amberlite IR
120H+, £ 2 cm 40 cm) at 5 mL min1 to protonate the acids.
The eluent (pH 2) was vacuum distilled at 70–80 C, filtered
(0.45 lm nylon), to obtain a concentrated solution of LA.