Nisin, temperature and pH effects on growth and viability of Pectinatus frisingensis, a Gram-negative, strictly anaerobic beer-spoilage bacterium

Abstract

Pectinatus frisingensis, a Gram‐negative and strictly anaerobic beer spoilage bacterium is sensitive to nisin. An increase in nisin concentration (0 to 1100 IU ml−1) added to the culture medium prolonged the lag phase, and decreased the growth rate of the bacterium. In addition, late exponential cells of P. frisingensis exposed to low concentrations of nisin lost immediately a part of their intracellular K+. Presence of Mg2+ up to 15 mmol l−1 did not protect P. frisingensis from nisin‐induced loss of viability and K+ efflux. Potassium leaks were also measured in P. frisingensis late exponential phase cells exposed to combined effects of nisin addition (100–500 IU ml−1), 10 min mild heat‐treatment (50 °C) or rapid cooling (2 °C), and pH (4·0 and 6·2). Net K+ efflux from both starving and glucose‐metabolizing cells, was more important at pH 6·2, whatever the temperature treatment and nisin addition. Reincubation at 30 °C of P. frisingensis glucose‐metabolizing cells exposed to a preliminary combination of nisin addition and mild heat or cooling down treatment, showed that cells exposed to rapid cooling reaccumulated more K+ than heat‐treated cells, whatever the pH conditions. A combination of nisin and mild heat‐treatment could thus be of interest to prevent P. frisingensis growth in beers.

Pectinatus sottacetonis sp. nov., isolated from a commercial pickle spoilage tank

“…This differs from previous findings where Pectinatus cerevisiiphilus was found to be highly sensitive to vancomycin (Helander et al, 1994) and Pectinatus frisingensis was shown to be sensitive to nisin (Chihib et al, 1999). FSRU B0405…”

Pectinatus, Megasphaera and Zymophilus

“…This surprising result is explained by findings indicating that the outer membrane of Pectinatus does not form an effective barrier: the above study also demonstrated a high sensitivity of Pectinatus strains to vancomycin and bacitracin, which are rather large molecules (M r , 1449 and 1411, respectively) unable to penetrate a normal outer membrane in most bacteria (Vaara, 1993). Furthermore, P. frisingensis was shown to be sensitive to nisin, which is a cationic peptide acting lethally on the bacterial cytoplasmic membrane, but is unable to penetrate an intact outer membrane (Chihib et al, 1999b). Gram-negative bacteria are normally insensitive to nisin action (Helander et al, 1997).…”

“…A number of studies on Pectinatus growth in the culture medium as a function of temperature, pH and ethanol concentration have been performed (Tholozan et al, 1996;Tholozan et al, 1997;Chihib and Tholozan, 1999a;Chihib et al, 1999b) including modeling of growth and metabolite production (Membré and Tholozan, 1994;Watier et al, 1996b). In general, the parameters derive from those encountered in beer production, including rapid temperature changes in pasteurization and cooling before bottling.…”

125th Anniversary Review: Microbiological Instability of Beer Caused by Spoilage Bacteria

“…Notably P. cerevisiiphilus has been shown to be susceptible to vancomycin and bacitracin 67 , which are large molecules that are normally unable to penetrate the outer membrane of Gram-negative bacteria. It has also been demonstrated that P. frisingensis is sensitive to nisin, a large antibacterial peptide that normally does not affect Gram-negative bacteria 27 . These results suggest that the outer membrane of Pectinatus, in the conditions tested, does not act as an effective permeability barrier.…”