engleski

Activity of alginate-encapsulated Lactobacillus amylovorus DSM 20531T cells and their performance in production of lactate esters

Encapsulation of lactic acid bacterial strain Lactobacillus amylovorus DSM 20531T was used as a tool to maintain and preserve unique metabolic activity of this biocatalyst under industrially applicable conditions. In addition, the encapsulation in modified alginate beads served as a barrier between two processes: (i) direct production of D-/L- lactate from starch by the biocatalyst, and (ii) acid-catalyzed esterification of produced lactates by ethanol to ethyl lactates. The first process took place within the beads while the esterification was conducted in alcohol solution in which the beads were submerged. L. amylovorus DSM 20531T was succesfully encapsulated in spherical soft but robust beads, grew and retained its amylolytic and fermentative activity. The two targeted activities of the strain occured simultaneously within the beads, as it was well described for parallel saccharification and fermentation performed by suspended L. amylovorus DSM 20531T cells. Highly efficient hydrolysis of beads- integrated starch by the strain resulted in dissolution of the beads that otherwise were stable and retained their size, shape and color under severe conditions. Two optimized HPLC methods were used for characterization of the two activities of the biocatalyst: maltooligosaccharides, maltose and glucose, that were obtained by amylolytic activity, and fermentatively formed D-/L-lactate were quantified in the alcohol solution. Ethyl lactate was identified by gas chromatograph with MS detector, and quantification of data was done by the calibration with standard sample.

Lactobacillus amylovorus, incasuplation, starch, lactate, esters

nije evidentirano