Alicyclobacillus acidoterrestris is a spore-forming bacterium of importance to the fruit juice industry due to its remarkable heat resistance and production of guaiacol taint. Whole genome sequencing analysis reveals species demarcation corresponds to the two major genotypic groups to which A. acidoterrestris isolates belong. Heat resistance was significantly different between genotypic groups 1 and 2 with D₉₀ values of 15.5 and 9.3 min, respectively (p < 0.01). Comparison of squalene-hopene cyclase (shc) encoding sequences reveals non-synonymous changes and the alteration of glutamine residues. Glutamine absence may link to the stability reinforcement of the enzyme structure against thermal denaturation. Genomic islands harbouring heavy metal resistance genes are found in the majority of genotypic group 1 genomes (63%) but occurs in only one genome (5%) of genotypic group 2. Distribution of the genomic islands in the genotypic groups 1 and 2 is also consistent with phylogenetic trees and ANI and dDDH values. Subsequently, we propose genotypic group 1 as a new species closely related to A. acidoterrestris that possesses enhanced heat resistance.

Item Type:	Refereed Article
Keywords:	spore-forming bacteria, Alicyclobacillus acidoterrestris, acidic beverages, fruit-containing drinks, genetic and phenotypic diversity, guaiacol, fruit juice, vegetable juice, spoilage, genomics, D-value, spores, heat resistance, hopanoids
Research Division:	Agricultural, Veterinary and Food Sciences
Research Group:	Food sciences
Research Field:	Food chemistry and food sensory science
Objective Division:	Manufacturing
Objective Group:	Processed food products and beverages (excl. dairy products)
Objective Field:	Processed fruit and vegetable products (incl. juices)
UTAS Author:	Luong, TSV (Mr Van Luong)
UTAS Author:	Bowman, JP (Associate Professor John Bowman)
ID Code:	142663
Year Published:	2021
Web of Science® Times Cited:	5
Deposited By:	TIA - Research Institute
Deposited On:	2021-02-04
Last Modified:	2021-09-03
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