Kombucha and Water Kefir Grains Microbiomes’ Symbiotic Contribution to Postbiotics Enhancement

Abstract

Wild artisanal cultures, such as a symbiotic culture of bacteria and yeasts (SCOBY) and water kefir grains (WKG), represent a complex microorganism consortia that is composed of yeasts and lactic and acetic acid bacteria, with large strains of diversity and abundance. The fermented products (FPs) obtained by the microbiome’s contribution can be included in functional products due to their meta-biotics (pre-, pro-, post-, and paraprobiotics) as a result of complex and synergistic associations as well as due to the metabolic functionality. In this study, consortia of both SCOBY and WKG were involved in the co-fermentation of a newly formulated substrate that was further analysed, aiming at increasing the postbiotic composition of the FPs. Plackett–Burman (PBD) and Response Surface Methodology (RSM) techniques were employed for the experimental designs to select and optimise several parameters that have an influence on the lyophilised starter cultures of SCOBY and WKG activity as a multiple inoculum. Tea concentration (1–3%), sugar concentration (5–10%), raisins concentration (3–6%), SCOBY lyophilised culture concentration (0.2–0.5%), WKG lyophilised culture concentration (0.2–0.5%), and fermentation time (5–7 days) were considered the independent variables for mathematical analysis and fermentation conditions’ optimisation. Antimicrobial activity against Bacillus subtilis MIUG B1, Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Aspergillus niger MIUG M5, antioxidant capacity (DPPH), pH and the total acidity (TA) were evaluated as responses. The rich postbiotic bioactive composition of the FP obtained in optimised biotechnological conditions highlighted the usefulness of the artisanal co-cultures, through their symbiotic metabolic interactions for the improvement of bioactive potential.

Pangenome reconstruction of Lactobacillaceae metabolism predicts species-specific metabolic traits

“…Of these, four were found to be involved in the transport of dipeptides. These dipeptides have been shown to be produced by yeast and consumed by Lactobacillaceae during kefir fermentation ( 25 ). Three of the reactions have been associated with thiamine metabolism, in line with the high vitamin B1 content that has been reported in kefir ( 26 ).…”

Multi-omics characterization of the microbial populations and chemical space composition of a water kefir fermentation

“…The majority of reports on the composition of water kefir report Lactobacillus and Acetobacter as the representative genera in these fermentation processes ( Gulitz et al, 2011 ; Fiorda et al, 2017 ; Verce et al, 2019 ). Some previous studies have also described dominant bacteria of the genera Streptococcus , Leuconostoc, and Lactococcus and yeast genera such as Dekkera and Saccharomyces ( Laureys et al, 2022 ; Pihurov et al, 2023 ). Contrary to this last report, we found in our WK a hybrid matrix with a major presence of Lactobacillus sp.…”

“…In recent years, the popularity of these foods, including kombucha and kefir, has increased based on the potential health benefits that have been ascribed to them based on the metabiotics, which can be grouped into prebiotics, probiotics, and postbiotics produced by these products ( Marco et al, 2020 ; Pihurov et al, 2023 ). These biological activities can be related to the production of biochemical reactions triggered by multiple microorganisms that result in the release of vitamins, amino acids, exopolysaccharides (EPS), and organic acids, among other bioactive compounds ( Diez-Ozaeta and Astiazaran, 2022 ).…”