Application of Micropore Device for Accurate, Easy, and Rapid Discrimination of Saccharomyces pastorianus from Dekkera spp.

Kazumichi Yokota,Masateru Taniguchi,Yuji Kurokawa,Sanae Murayama,Hiroko Abe,Asae Takeo,Yoshihiro Nakajima,Kazuaki Kajimoto,Muneaki Hashimoto,Masato Tanaka,Masatoshi Kataoka

doi:10.3390/bios11080272

Abstract

Traceability analysis, such as identification and discrimination of yeasts used for fermentation, is important for ensuring manufacturing efficiency and product safety during brewing. However, conventional methods based on morphological and physiological properties have disadvantages such as time consumption and low sensitivity. In this study, the resistive pulse method (RPM) was employed to discriminate between Saccharomyces pastorianus and Dekkera anomala and S. pastorianus and D. bruxellensis by measuring the ionic current response of cells flowing through a microsized pore. The height and shape of the pulse signal were used for the simultaneous measurement of the size, shape, and surface charge of individual cells. Accurate discrimination of S. pastorianus from Dekkera spp. was observed with a recall rate of 96.3 ± 0.8%. Furthermore, budding S. pastorianus was quantitatively detected by evaluating the shape of the waveform of the current ionic blockade. We showed a proof-of-concept demonstration of RPM for the detection of contamination of Dekkera spp. in S. pastorianus and for monitoring the fermentation of S. pastorianus through the quantitative detection of budding cells.

Highlights

The resistive pulse method (RPM) is used for evaluating the transient ionic current blockade associated with the translocation of individual nano- to microsized particles passing through an appropriate diameter pore
RPM can be expected to be as accurate as PCR. These results indicate the potential of Ip–td analysis by RPM for the quantitative detection of S. pastorianus in solution and the accurate detection of Dekkera spp. contamination
Smaller-sized pore is necessary to improve the resolution for analyzing the budding of Dekkera spp. These results indicate the potential application of RPM for the monitoring of growth viability and fermentation of yeasts by the quantitative detection of budding cells [30,31,32]

Summary

Introduction

The resistive pulse method (RPM) is used for evaluating the transient ionic current blockade associated with the translocation of individual nano- to microsized particles passing through an appropriate diameter pore. It is applicable in proving small objects by using pulse-like electrical signals. The genus Saccharomyces is well-known as the key yeast species in beer fermentation, and S. pastorianus is used in bottom-fermented beer [12]. The presence of Brettanomyces yeasts (teleomorph Dekkera) including Dekkera anomala and

Methods

Results

Conclusion