Comparison of metabolic response between the planktonic and air-dried Escherichia coli to electrolysed water combined with ultrasound by 1H NMR spectroscopy. (November 2019)

• Record Type: Journal Article
• Authors: Zhao, Lin; Zhao, Xue; Wu, Ji'en; Lou, Xiaowei; Yang, Hongshun
• Is Part Of: Food research international. Volume 125(2019)
• Publication Date: 2019-11
• Subjects: Metabolomics -- NMR -- Principal component analysis -- Oxidative stress -- Pathway analysis -- Air-dried cell -- Stainless steel coupon -- Omics; Food -- Analysis -- Periodicals; Food industry and trade -- Periodicals; Food industry and trade -- Canada -- Periodicals; Food Technology -- Periodicals; Food -- Periodicals; Food-Processing Industry -- Periodicals; Aliments -- Industrie et commerce -- Périodiques; Aliments -- Industrie et commerce -- Canada -- Périodiques; Aliments -- Recherche -- Périodiques; Food industry and trade; Canada; Periodicals; Electronic journals; 664.005
• DOI: 10.1016/j.foodres.2019.108607
• Languages: English
• ISSNs: 0963-9969

Abstract

Abstract: The antimicrobial effects of electrolysed water and ultrasound have been well reported; however, little attention was paid to their effects on the metabolite changes of bacteria in different states. In this study, the metabolomic variations of Escherichia coli ATCC 25922 in planktonic and adherent state (air-dried on stainless steel coupons) after the combination treatment of low-concentration acidic electrolysed water (AEW, free available chlorine (FAC): 4 mg/L) and ultrasound were characterised, by conducting multivariate data analysis based on nuclear magnetic resonance (NMR) spectroscopy. Overall, 43 metabolites were identified in two states of E. coli, including a wide range of amino acids, organic acids, nucleotides and their derivatives. The quantification of whole-cell metabolism in planktonic and air-dried cultures was quite different: air-dried E. coli exhibited more resistance to ultrasound and AEW treatments due to initiating a protective response against oxidative and acid stresses, which was not observed in planktonic E. coli, whose levels of all identified metabolites were decreased significantly after the combined treatment. Further pathway analysis revealed that alanine, aspartate and glutamate metabolism, glycolysis, pyruvate metabolism and tricarboxylic acid (TCA) cycle were changed significantly in planktonic culture, but to a less extent in air-dried culture, in which some shifts in glutamate decarboxylase (GAD) system and some shunts like mixed acid fermentation and pentose phosphate pathway were observed for maintaining metabolic balance. These findings suggest that NMR-based metabolomics strategy is promising in identifying different metabolic shifts in different states of bacteria. They also provide some guidance for food equipment sanitisation, especially for organic food processing. Graphical abstract: Unlabelled Image Highlights: Low-concentration acidic electrolysed water was combined with ultrasound. Escherichia coli in planktonic and air-dried had different metabolic responses. 43 metabolites were identified in two states of E. coli . Air-dried E. coli exhibited more resistance due to protective responses. Metabolic pathways were altered in two states of E. coli.