Harvey Harry J, Szepe Kamil J, Hendry Alex C, Archer David B, Avery Simon V
School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, UK.
School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, UK.
Int J Food Microbiol. 2025 Dec 2;443:111439. doi: 10.1016/j.ijfoodmicro.2025.111439. Epub 2025 Sep 9.
Brettanomyces bruxellensis is an emerging spoilage yeast of low-sugar ethanol fermentation processes and alcoholic beverages. As soft (non-alcoholic) drinks manufacturers transition towards low sugar formulations, this study investigated the ability of B. bruxellensis to grow in different soft-drink and preservative conditions. Multiple B. bruxellensis isolates grew comparably to the common spoilage yeast Z. bailii in a variety of soft drink formulations, including zero sugar lemonades, low-sugar fruit juices, and carbonated beverages. Growth assays with B. bruxellensis in laboratory minimal-medium supplemented with low (0.1 %) glucose were characterised by turbid biomass accumulation (a spoilage indicator) and resistance to the major food preservative sorbic acid (SA), known to cause oxidative stress and to inhibit respiration. Analysis of respiro-fermentative metabolism revealed that B. bruxellensis favoured respiration over fermentation regardless of glucose concentration, with oxygen limitation significantly reducing its growth. Cell-to-cell heterogeneity was used as a tool to test whether cellular levels of respiratory reactive oxygen species (ROS) influence the organism's SA resistance phenotype. At low glucose, sorted cell-subpopulations with high background ROS were more SA resistant than low ROS cells. Furthermore, the antioxidant N-acetyl cysteine (NAC) hyper-sensitized these cell subpopulations to SA. Therefore, one explanation for SA resistance despite the organism's primarily respiratory metabolism could be that respiratory ROS builds cells' resilience to (subsequent) SA-induced oxidative stress. The work shows that B. bruxellensis is capable of growth in zero- or low-sugar media and drinks formulations, and in the presence of relatively high sorbic acid levels.
布鲁塞尔酒香酵母是低糖乙醇发酵过程和酒精饮料中一种新出现的腐败酵母。随着软（非酒精）饮料制造商向低糖配方转型，本研究调查了布鲁塞尔酒香酵母在不同软饮料和防腐剂条件下的生长能力。在多种软饮料配方中，包括无糖柠檬水、低糖果汁和碳酸饮料，多种布鲁塞尔酒香酵母分离株的生长情况与常见的腐败酵母拜耳接合酵母相当。在补充了低浓度（0.1%）葡萄糖的实验室基本培养基中对布鲁塞尔酒香酵母进行的生长试验，其特征在于浑浊的生物量积累（一种腐败指标）以及对主要食品防腐剂山梨酸（SA）的抗性，已知山梨酸会引起氧化应激并抑制呼吸作用。对呼吸发酵代谢的分析表明，无论葡萄糖浓度如何，布鲁塞尔酒香酵母都更倾向于呼吸作用而非发酵作用，氧气限制会显著降低其生长。细胞间异质性被用作一种工具，以测试呼吸性活性氧（ROS）的细胞水平是否会影响该生物体的SA抗性表型。在低葡萄糖条件下，具有高背景ROS的分选细胞亚群比低ROS细胞对SA更具抗性。此外，抗氧化剂N-乙酰半胱氨酸（NAC）使这些细胞亚群对SA高度敏感。因此，尽管该生物体主要进行呼吸代谢但仍具有SA抗性的一种解释可能是，呼吸性ROS增强了细胞对（随后的）SA诱导的氧化应激的恢复能力。这项工作表明，布鲁塞尔酒香酵母能够在无糖或低糖培养基和饮料配方中生长，并且能够在相对较高的山梨酸水平下生长。
