Abstract

To elucidate the mechanisms underlying the hop-resistance ability of beer-spoilage lactic acid bacteria, we attempted to isolate hop-sensitive variants from beer-spoilage Lactobacillus brevis. As a result, the repeated subcultures at 37°C were found to cause the hop resistance of six beer-spoilage L. brevis strains to be lost. In contrast to the wild-type strains, the hop-resistance ability of these variants was no longer inducible, as indicated by the inability to grow in DeMan-Rogosa-Sharpe (MRS) media supplemented with progressively higher concentrations of hop compounds. The diminished adaptability to hop compounds was comparable with that of the originally non-spoilage L. brevis strain, JCM1059T. When the variants were inoculated in beer and incubated anaerobically at 25°C, the viability of the strains was lost within one week, whereas the wild-type strains were able to grow during the same period of incubation. From these observations, it has been concluded that the variants obtained in this study lost the beer-spoilage ability. The biochemical characterization of the variants revealed narrower carbohydrate utilization profiles in some of the strains, notably with regard to the ability to ferment maltose.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.