Genotypic and Phenotypic Heterogeneity in Alicyclobacillus acidoterrestris: A Contribution to Species Characterization

Abstract

Alicyclobacillus acidoterrestris is the main cause of most spoilage problems in fruit juices and acidic products. Since soil borne species often contaminate fruit juices and do not need strict extreme requirements for survival, it is a great concern to investigate whether and how soil species could evolve from their ecological niches in microbial community to new environments as fruit juices. In this study, 23 isolates of thermo-acidophilic, spore-forming bacteria from soil were characterized by cultural and molecular methods. In addition, 2 strains isolated from a spoilage incident in pear juice were typed. Strains phenotyping showed that they could be grouped into 3 different clusters, and some isolates showed identical or quite similar patterns. Analyzing pH and temperature ranges for growth, the majority of strains were able to grow at values described for many species of Alicyclobacillus. Qualitative utilization of lysine, arginine and indole production from tryptophan revealed, for the first time, deamination of lysine and decarboxylation of arginine. Resistance to 5% NaCl as well as the ability to hydrolyze starch and gelatin, nitrate reduction, catalase and oxidase activities confirmed literature evidences. Examining of 16S rRNA, showed that isolates were divided into three blocks represented by effectively soil species and strains that are moving from soil to other possible growing source characterized by parameters that could strongly influence bacterial survival. RAPD PCR technique evidenced a great variability in banding patterns and, although it was not possible to obtain genotypically well-distinguished groups, it was feasible to appreciate genetic similarity between some strains. In conclusion, the investigation of a microbial community entails a combination of metagenomic and classic culture-dependent approaches to expand our knowledge about Alicyclobacillus and to look for new subspecies.

Maintaining Physicochemical, Microbiological, and Sensory Quality of Pineapple Juice (Ananas comosus, Var. ‘Queen Victoria’) through Mild Heat Treatment

“…However, this bacterium is involved in spoilage of shelf-stable acid beverages. In this study, its growth can be controlled by the low temperature of storage [30,31].…”

Bacillus velezensis AP183 Inhibits Staphylococcus aureus Biofilm Formation and Proliferation in Murine and Bovine Disease Models

“…The only other genus in which a significant change was observed in the milk microbiome was an increase in the relative abundance of the genus Alicyclobacillus from D 0 to D 8 in the treatment group. This soil borne genus is usually associated with the spoilage of fruit juices (Groenewald et al, 2009;Bevilacqua et al, 2015). This may indicate that the growth substrates used by Alicyclobacillus spp.…”

Viability, Sublethal Injury, and Release of Cellular Components From Alicyclobacillus acidoterrestris Spores and Cells After the Application of Physical Treatments, Natural Extracts, or Their Components

“…The following strains were used: (i) A. acidoterrestris DSM 3922 T from Deutsche Sammlung von Mikroorganismem und Zellkulturen's collection, Braunschweig, Germany; and (ii) A. acidoterrestris C8, C24, and CB1, belonging to the collection of the Department of Agriculture, Food, Natural Resources and Engineering (Foggia University), and isolated from soil and a spoiled pear juice ( 27 ). The strains of A. acidoterrestris were stored at 4°C on malt extract agar (MEA) (Oxoid, Milan, Italy) and acidified to pH 4.5 through a sterile solution of citric acid (1:1, w/w).…”