초록
<P><B>Abstract</B></P><P>The aim of this study was to select among lactic acid bacteria (LAB) and yeast a potential β-galactosidase producer, based on bioprocess parameters. From the selected microorganism, different organic cheaper nitrogen sources (single and combined) with low cost for β-galactosidase production were evaluated.<I>Lactobacillus reuteri</I>B-14171 showed the highest enzymatic activity (1,286 U L<SUP>−1</SUP>), high productivity (28.78 U L h<SUP>−1</SUP>) and yield factor (82.32 U g<SUP>−1</SUP>), evidencing its potential for β-galactosidase production. All organic nitrogen sources tested were viable for the enzymatic production using<I>L. reuteri</I>B-14171. The MMRS casein (3.0 g L<SUP>−1</SUP>) + inactive beer yeast (3.0 g L<SUP>−1</SUP>) as nitrogen source increased the enzymatic activity (1269 U L<SUP>−1</SUP>) with 1.83 times lower production costs of culture medium when compared to MMRS-yeast extract B. The MMRS casein + inactive beer yeast has proved to be an innovative and cheaper nitrogen source for β-galactosidase production by<I>L. reuteri</I>B-14171.</P>