• Analysis of Health Benefits Conferred by Lactobacillus Species from Kefir

      Cotter, Paul D.; Slattery, Conor; O'Toole, Paul W.; Department of Agriculture, Food and Marine; Science Foundation Ireland; APC Microbiome Ireland; Vistamilk; Enterprise Ireland; European Union; 818368 (MDPI, 2019-06-01)
      Lactobacilli are among the most common microorganisms found in kefir; a traditional fermented milk beverage produced locally in many locations around the world. Kefir has been associated with a wide range of purported health benefits; such as antimicrobial activity; cholesterol metabolism; immunomodulation; anti-oxidative effects; anti-diabetic effects; anti-allergenic effects; and tumor suppression. This review critically examines and assesses these claimed benefits and mechanisms with regard to particular Lactobacillus species and/or strains that have been derived from kefir; as well as detailing further potential avenues for experimentation.
    • Hydrogel-based Bio-nanomachine Transmitters for Bacterial Molecular Communications

      Martins, Daniel P.; O'Reilly, Huong Q.; Coffey, Lee; Cotter, Paul D.; Balasubramaniam, Sasitharan; Science Foundation Ireland; Department of Agriculture, Food and Marine; 16/RC/3835 (ACM, 2020-11-16)
      Bacterial quorum sensing can be engineered with a view to the design of biotechnological applications based on their intrinsic role as a means of communication. We propose the creation of a positive feedback loop that will promote the emission of a superfolded green fluorescence protein from a bacterial population that will flow through hydrogel, which is used to encapsulate the cells. These engineered cells are heretofore referred to as bio-nanomachine transmitters and we show that for lower values of diffusion coefficient, a higher molecular output signal power can be produced, which supports the use of engineered bacteria contained within hydrogels for molecular communications systems. In addition, our wet lab results show the propagation of the molecular output signal, proving the feasibility of engineering a positive feedback loop to create a bio-nanomachine transmitter that can be used for biosensing applications.
    • Meta-analysis of cheese microbiomes highlights contributions to multiple aspects of quality

      Walsh, Aaron M.; Macori, Guerrino; Kilcawley, Kieran N.; Cotter, Paul D.; Science Foundation Ireland; European Commission; Department of Agriculture, Food and Marine; SFI/12/RC/2273P1; SFI/12/RC/2273P2; 818368; et al. (Springer Science and Business Media LLC, 2020-08-13)
      A detailed understanding of the cheese microbiome is key to the optimization of flavour, appearance, quality and safety. Accordingly, we conducted a high-resolution meta-analysis of cheese microbiomes and corresponding volatilomes. Using 77 new samples from 55 artisanal cheeses from 27 Irish producers combined with 107 publicly available cheese metagenomes, we recovered 328 metagenome-assembled genomes, including 47 putative new species that could influence taste or colour through the secretion of volatiles or biosynthesis of pigments. Additionally, from a subset of samples, we found that differences in the abundances of strains corresponded with levels of volatiles. Genes encoding bacteriocins and other antimicrobials, such as pseudoalterin, were common, potentially contributing to the control of undesirable microorganisms. Although antibiotic-resistance genes were detected, evidence suggested they are not of major concern with respect to dissemination to other microbiomes. Phages, a potential cause of fermentation failure, were abundant and evidence for phage-mediated gene transfer was detected. The anti-phage defence mechanism CRISPR was widespread and analysis thereof, and of anti-CRISPR proteins, revealed a complex interaction between phages and bacteria. Overall, our results provide new and substantial technological and ecological insights into the cheese microbiome that can be applied to further improve cheese production.
    • Ultrasound-assisted extraction of polyphenols from potato peels: profiling and kinetic modelling

      Kumari, Bibha; Tiwari, Brijesh K; Hossain, Mohammad Billal; Rai, Dilip K.; Brunton, Nigel; Department of Agriculture, Food and Marine; FIRM/11/F/050 (Wiley, 2017-02-14)
      Ultrasound‐assisted extraction (UAE) at 33 and 42 kHz has been investigated in the extraction of polyphenols from peels of two potato varieties, cream‐skinned Lady Claire (LC) and pink‐skinned Lady Rosetta (LR), commonly used in snack food production. Extraction efficacy between the UAE‐untreated (control) and the UAE‐treated extracts was assessed on the total phenolic content and antioxidant capacities (DPPH and FRAP). Application of UAE showed significantly higher recovery of phenolic compounds compared to solid–liquid extraction process alone. Lower ultrasonic frequency (33 kHz) was more effective in recovering polyphenols compared to 42 kHz ultrasonic treatment. The liquid chromatography‐tandem mass spectrometry revealed that chlorogenic acid and caffeic acid were the most prevalent phenolics in LR peels, whereas caffeic acid was dominant in LC peels. Peleg's equation showed a good correlation (R2 > 0.92) between the experimental values and the predicted values on the kinetics of UAE of phenolic compounds.