Tetragenococcus halophilus is known to flourish in extreme salt environments. Recently, this
halophilic bacterium also appeared as the dominant microflora during storage of sugar thick juice,
an intermediate product of beet sugar production. Although T. halophilus can cause degradation
of thick juice, dominance of this bacterium does not always result in degradation. In this study
T. halophilus strains from high-salt and high-sugar environments, and in particular from degraded
and non-degraded thick juice, were compared in detail. Both physiological and genetic
characterization using Biolog, repetitive extragenic palindrome PCR fingerprinting (REP-PCR)
and random amplified polymorphic DNA (RAPD) technology, revealed clear differences between
T. halophilus strains isolated from salt- and sugar-rich environments. However, no strain pattern
could be specifically and systematically associated with degraded or non-degraded thick juice.
Remarkably, halophilic T. halophilus strains were not able to grow in sugar thick juice. Irrespective
of the differences between the strains from high-salt or high-sugar environments, DNA–DNA
hybridization grouped all strains within the species T. halophilus, except one isolate from sugar
thick juice that showed different physiological and genetic characteristics, and that may represent
a new species of Tetragenococcus.