Diversity of Acetobacter pasteurianus strains isolated from solid-state fermentation of cereal vinegars.

Vinegar production is based on the acetification process by indigenous acetic acid bacteria (AAB). Among vinegar technologies, solid-state fermentation (SSF) processes are widespread in Asian countries to produce vinegar at small-scale. In this study, 21 AAB strains isolated from Chinese cereal vinegars produced by SSF collected in different regions of China were characterized by enterobacterial repetitive intergenic consensus (ERIC)-PCR fingerprinting. Isolates exhibited high degree of phenotypic variability as well as suitable traits for their uses as selected strains in SSF vinegar production (growth modality by superficial biofilm, no production of cellulose, ability to growth on ethanol media). 16S rRNA gene sequencing analysis of representative strains showed that strains of Acetobacter pasteurianus have a close association to cereal vinegars, whereas Gluconacetobacter europaeus population is not favoured. Selection of single or multiple strains culture within A. pasteurianus species was predicted in view of their application in SSF technology. This seems to be the first report showing phenotypic and genetic variability of AAB strains involved in SSF processes. Results can be exploited for the implementation of large-scale SSF processes by selected strains for vinegar production and other innovative biotechnological applications.