Assessment of the microbial diversity during an industrial-scale malting process by a polymerase chain reaction-denaturing gradient gel electrophoresis analysis

Abstract

Assessing the microbial diversity during malting is an essential step towards process management and optimization. However, microbial characterization of the malting process has mostly been performed using culture-dependent methods, which has probably led to biased microbial diversity estimates. The aim of this study was to characterize the bacterial communities during an industrial-scale malting process using polymerase chain reaction-denaturing gradient gel electrophoresis. The main bacterial strains in the malting process were identified as Sphingomonas spp., Enterobacter spp., Neisseria spp., Escherichia spp., Rhodocyclus spp., Erwinia spp. and Klebsiella spp. according to the GenBank database. The results revealed that the bacterial community structure changed during the malting process, and that the diverse microbial community played an active role in the malting ecosystem. Moreover, the dominant species changed with the aeration conditions during malting, and there was a tendency for aerobic bacteria to gradually become the predominant community during malting. An improved understanding of the complex microbial community during malting enables greater process management control and the production of high-quality malt.