Laboratory of Food Microbiology, Wageningen University & Research, Wageningen Campus, PO Box 17, 6700 AA, Wageningen, The Netherlands.
Microb Biotechnol. 2017 Nov;10(6):1591-1602. doi: 10.1111/1751-7915.12717. Epub 2017 Aug 18.
Increasing interest in new beer types has stimulated the search for approaches to extend the metabolic variation of brewers' yeast. Therefore, we tested two approaches using non-conventional yeast to create a beer with lower ethanol content and a complex aroma bouquet. First, the mono-culture performance was monitored of 49 wild yeast isolates of Saccharomyces cerevisiae (16 strains), Cyberlindnera fabianii (9 strains) and Pichia kudriavzevii (24 strains). Interestingly, both C. fabianii and P. kudriavzevii isolates produced relatively more esters compared with S. cerevisiae isolates, despite their limited fermentation capacity. Next, one representative strain of each species (Sc131, Cf65 and Pk129) was applied as co-culture with brewers' yeast (ratio 1:1). Co-cultures with Cf65 and Pk129 resulted in a beer with lower alcohol content (3.5, 3.8 compared with 4.2% v/v) and relatively more esters. At higher inoculum ratios of Cf65 over brewers' yeast, growth inhibition of brewers' yeast was observed, most likely caused by competition for oxygen between brewers' yeast and Cf65 resulting in a reduced level of ethanol and altered aroma profiles. With this study, we demonstrate the feasibility of using non-conventional yeast species in co-cultivation with traditional brewers' yeast to tailor aroma profiles as well as the final ethanol content of beer.
对新型啤酒的兴趣日益浓厚，这促使人们寻求方法来扩大啤酒酵母的代谢变化。因此，我们使用非常规酵母测试了两种方法，以创造一种乙醇含量较低且具有复杂香气的啤酒。首先，监测了 49 株野生酿酒酵母（16 株）、Cyberlindnera fabianii（9 株）和 Pichia kudriavzevii（24 株）的单培养性能。有趣的是，尽管 C. fabianii 和 P. kudriavzevii 菌株的发酵能力有限，但与酿酒酵母菌株相比，它们产生的酯类相对更多。接下来，将每种物种（Sc131、Cf65 和 Pk129）的一个代表菌株分别与啤酒酵母（比例为 1:1）进行共培养。Cf65 和 Pk129 的共培养导致啤酒的酒精含量降低（3.5%和 3.8%，而传统啤酒的酒精含量为 4.2%），且酯类相对更多。当 Cf65 相对于啤酒酵母的接种物比例较高时，会观察到啤酒酵母的生长受到抑制，这很可能是由于啤酒酵母和 Cf65 之间对氧气的竞争，导致乙醇水平降低和香气特征改变。通过这项研究，我们证明了在与传统啤酒酵母共培养中使用非常规酵母物种来调整香气特征以及啤酒最终乙醇含量的可行性。
