Description:
<jats:title>ABSTRACT</jats:title>
<jats:p>
A plasmid-borne diacetyl (acetoin) reductase (
<jats:italic>butA</jats:italic>
) from
<jats:italic>Leuconostoc pseudomesenteroides</jats:italic>
CHCC2114 was sequenced and cloned. Nucleotide sequence analysis revealed an open reading frame encoding a protein of 257 amino acids which had high identity at the amino acid level to diacetyl (acetoin) reductases reported previously. Downstream of the
<jats:italic>butA</jats:italic>
gene of
<jats:italic>L. pseudomesenteroides</jats:italic>
, but coding in the opposite orientation, a putative DNA recombinase was identified. A two-step PCR approach was used to construct FPR02, a
<jats:italic>butA</jats:italic>
mutant of the wild-type strain, CHCC2114. FPR02 had significantly reduced diacetyl (acetoin) reductase activity with NADH as coenzyme, but not with NADPH as coenzyme, suggesting the presence of another diacetyl (acetoin)-reducing activity in
<jats:italic>L. pseudomesenteroides</jats:italic>
. Plasmid-curing experiments demonstrated that the
<jats:italic>butA</jats:italic>
gene is carried on a 20-kb plasmid in
<jats:italic>L. pseudomesenteroides</jats:italic>
.
</jats:p>