Department of Agriculture, University of Sassari, Sassari, Italy.
Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy.
Appl Microbiol Biotechnol. 2017 Apr;101(7):2931-2942. doi: 10.1007/s00253-016-8050-2. Epub 2016 Dec 28.
The use of natural antimicrobials from plants, animals and microorganisms to inhibit the growth of pathogenic and spoilage microorganisms is becoming more frequent. This parallels the increased consumer interest towards consumption of minimally processed food and 'greener' food and beverage additives. Among the natural antimicrobials of microbial origin, the killer toxin produced by the yeast Tetrapisispora phaffii, known as Kpkt, appears to be a promising natural antimicrobial agent. Kpkt is a glycoprotein with β-1,3-glucanase and killer activity, which induces ultrastructural modifications to the cell wall of yeast of the genera Kloeckera/Hanseniaspora and Zygosaccharomyces. Moreover, Kpkt maintains its killer activity in grape must for at least 14 days under winemaking conditions, thus suggesting its use against spoilage yeast in wine making and the sweet beverage industry. Here, the aim was to explore the possibility of high production of Kpkt for biotechnological exploitation. Molecular tools for heterologous production of Kpkt in Komagataella phaffii GS115 were developed, and two recombinant clones that produce up to 23 mg/L recombinant Kpkt (rKpkt) were obtained. Similar to native Kpkt, rKpkt has β-glucanase and killer activities. Moreover, it shows a wider spectrum of action with respect to native Kpkt. This includes effects on Dekkera bruxellensis, a spoilage yeast of interest not only in wine making, but also for the biofuel industry, thus widening the potential applications of this rKpkt.
植物、动物和微生物来源的天然抗菌剂用于抑制致病菌和腐败微生物的生长变得越来越普遍。这与消费者对食用低加工食品和“更环保”的食品和饮料添加剂的兴趣日益增加是一致的。在微生物来源的天然抗菌剂中，由酿酒酵母 Tetrapisispora phaffii 产生的杀伤毒素，即 Kpkt，似乎是一种很有前途的天然抗菌剂。Kpkt 是一种具有 β-1,3-葡聚糖酶和杀伤活性的糖蛋白，它诱导酵母属（Kloeckera/Hanseniaspora 和 Zygosaccharomyces）细胞壁的超微结构发生改变。此外，Kpkt 在酿酒条件下至少在葡萄汁中保持其杀伤活性 14 天，因此可以用于防止葡萄酒和甜饮料工业中的酵母腐败。在这里，目的是探索 Kpkt 用于生物技术开发的高产量生产的可能性。开发了在 Komagataella phaffii GS115 中异源生产 Kpkt 的分子工具，并获得了两个产生高达 23mg/L 重组 Kpkt（rKpkt）的重组克隆。与天然 Kpkt 相似，rKpkt 具有 β-葡聚糖酶和杀伤活性。此外，它相对于天然 Kpkt 具有更广泛的作用谱。这包括对德克氏酵母（Dekkera bruxellensis）的影响，德克氏酵母不仅是葡萄酒酿造中的一种腐败酵母，而且也是生物燃料工业中的一种腐败酵母，从而扩大了这种 rKpkt 的潜在应用。
