Symbiotic Consortium Research Articles

Physico-chemical properties and lipid binding capacity of bacterial cellulose synthesized on whey

Bacterial cellulose (BC) has significant potential for applications in the food industry due to its ability to stabilize food dispersion systems. In this work, the efficiency of BC biosynthesis on dairy industry waste was investigated, and these process parameters were studied: amount of substrate, titratable acidity, mass of synthesized cellulose. The physico-chemical properties and lipid binding capacity of the obtained gel films and dehydrated polysaccharide samples were determined. Bacterial cellulose was obtained under static conditions, in a liquid nutrient medium – whey. Lactose from whey was preliminarily hydrolysed with the enzyme preparation LACTA FREE to a glucose content of 1.93%. The mass of cellulose produced under static conditions by the symbiotic consortium Medusomyces gisevii was 3.84 g/l over 21 days at T=31°C. A correlation was noted between low amounts of glucose in the culture fluid on the 6th day of biosynthesis and a decrease in titratable acidity. The degree of conversion of glucose from fermented whey to the mass of produced bacterial cellulose was 22.6%. The maximum biosynthesis rate of 0.181 gL-1×day-1 (dry weight) was established on the 15th day of the process. The water retention capacity of the synthesized bacterial cellulose gel films was determined to be 82.35 ± 0.63 g/g. Lyophilized samples of bacterial cellulose were characterized by a higher water absorption capacity (22.44 g/g) compared to samples dehydrated at T=50°C (5.42 g/g). It was found that rehydrated samples of lyophilized cellulose had a 3.43 times higher ratio of free and bound moisture compared to dried BC samples. The bulk density of disaggregated cellulose was determined: lyophilized - 20 kg/m3, thermally dried - 170 kg/m3. The work provides a comparative analysis of the lipid binding capacity of BC and chitosan. Microbiological parameters of disaggregated bacterial cellulose were determined.

IMPROVEMENT OF TRADITIONAL BALINESE "ONG" TEA-MAKING PROCESS TO EXTEND SHELF LIFE TO SUPPORT ECOTOURISM IN BANJAR LANTANGIDUNG, GIANYAR, BALI

“Ong” tea contains vitamins B1, B2, B6, B12, folic acid, and vitamin C, in addition to several essential amino acids, organic acids, minerals, vitamins, amino acids, and active polyphenol compounds, and various important enzymes that have many benefits for the body. “Ong” tea is a type of probiotic drink produced from the tea fermentation process. The bacteria contained in SCOBY (Symbiotic Consortium of Bacteria and Yeast) are Acetobacter xylinum bacteria. The purpose of implementing the activities proposed in the training to improve the process of making “Ong” tea through PKM activities is to ensure that the people of Br. Lantangidung, Batuan, Sukawati have the skills and insight to manage local natural resources and have an entrepreneurial spirit so that they can open up business opportunities related to the conditions of the Batuan Village area. Improving product quality, expanding marketing reach, and using more hygienic and modern packaging techniques are also important. Thus, it is hoped that Balinese “ong” tea can become a superior product that can improve the community's economy and support the development of ecotourism in Banjar Lantangidung

Metabolomic kinetics investigation of Camellia sinensis kombucha using mass spectrometry and bioinformatics approaches

Kombucha is created through the fermentation of Camellia sinensis tea leaves, along with sucrose, utilizing a symbiotic consortium of bacteria and yeast cultures. Nonetheless, there exists a dearth of comprehensive information regarding the spectrum of metabolites that constitute this beverage. To explore this intricate system, metabolomics was used to investigate fermentation kinetics of Kombucha. For that, an experimental framework was devised to assess the impact of varying sucrose concentrations and fermentation temperatures over a ten-day period of kombucha fermentation. Following fermentation, samples were analyzed using an LC-QTOF-MS system and a distinctive metabolomic profile was observed. Principal component analysis was used to discriminate between metabolite profiles. Moreover, the identified compounds were subjected to classification using the GNPS platform. The findings underscore notable differences in compound class concentrations attributable to distinct fermentation conditions. Furthermore, distinct metabolic pathways were identified, specially some related to the biotransformation of flavonoids. This comprehensive investigation offers valuable insights into the pivotal role of SCOBY in driving metabolite production and underscores the potential bioactivity harbored within Kombucha.

Honey-kombucha beverage with yerba maté infusion: Development, polyphenols profile, and sensory acceptance

Kombucha is a sweetened beverage made by fermenting a symbiotic consortium of bacteria (generally acetic acid bacteria) and yeasts (SCOBY) in black or green tea, with sucrose as source of carbohydrate. Other herbal infusions, such as yerba maté (Ilex paraguarienses), are used to produce kombucha-like beverages. Honey is a good source of sugar and biologically active components for kombucha-like development. The goal was to develop and characterize a fermented beverage from yerba maté infusion using a kombucha culture, with either sucrose or different types of honey from Apis bees and native Brazilian stingless bees. The fermentation process was studied for up to 20 days, monitoring pH, titratable acidity, reducing sugar and soluble protein, total phenolic compounds, chlorogenic acids, caffeine, and rutin. The sensory acceptance of the honey-kombucha-like beverage was also investigated. As fermentation progressed, the pH decreased, titratable acidity increased, and reducing sugars initially decreased due to SCOBY consumption, followed by an increase due to the conversion of non-reducing sugars to reducing sugars. The concentration of chlorogenic acids increased with fermentation, exceeding 300 μg/mL after 15 days. The aroma and flavor of the kombucha beverage received scores around 5–6 on a nine-point hedonic scale. These scores were linked to the high titratable acidity after the 10th day of fermentation and the “vinegar taste” reported by the subjects. To improve sensory acceptance, the fermentation length can be reduced to up to 10 days, resulting in a beverage with a pleasant fruity and sour aftertaste. However, this strategy may compromise the retention of high polyphenols, which is achieved through longer fermentations of around 15–20 days.

Characterization of gill bacterial microbiota in wild Arctic char (Salvelinus alpinus) across lakes, rivers, and bays in the Canadian Arctic ecosystems.

Teleost gill mucus has a highly diverse microbiota, which plays an essential role in the host's fitness and is greatly influenced by the environment. Arctic char (Salvelinus alpinus), a salmonid well adapted to northern conditions, faces multiple stressors in the Arctic, including water chemistry modifications, that could negatively impact the gill microbiota dynamics related to the host's health. In the context of increasing environmental disturbances, we aimed to characterize the taxonomic distribution of transcriptionally active taxa within the bacterial gill microbiota of Arctic char in the Canadian Arctic in order to identify active bacterial composition that correlates with environmental factors. For this purpose, a total of 140 adult anadromous individuals were collected from rivers, lakes, and bays belonging to five Inuit communities located in four distinct hydrologic basins in the Canadian Arctic (Nunavut and Nunavik) during spring (May) and autumn (August). Various environmental factors were collected, including latitudes, water and air temperatures, oxygen concentration, pH, dissolved organic carbon (DOC), salinity, and chlorophyll-a concentration. The taxonomic distribution of transcriptionally active taxa within the gill microbiota was quantified by 16S rRNA gene transcripts sequencing. The results showed differential bacterial activity between the different geographical locations, explained by latitude, salinity, and, to a lesser extent, air temperature. Network analysis allowed the detection of a potential dysbiosis signature (i.e., bacterial imbalance) in fish gill microbiota from Duquet Lake in the Hudson Strait and the system Five Mile Inlet connected to the Hudson Bay, both showing the lowest alpha diversity and connectivity between taxa.IMPORTANCEThis paper aims to decipher the complex relationship between Arctic char (Salvelinus alpinus) and its symbiotic microbial consortium in gills. This salmonid is widespread in the Canadian Arctic and is the main protein and polyunsaturated fatty acids source for Inuit people. The influence of environmental parameters on gill microbiota in wild populations remains poorly understood. However, assessing the Arctic char's active gill bacterial community is essential to look for potential pathogens or dysbiosis that could threaten wild populations. Here, we concluded that Arctic char gill microbiota was mainly influenced by latitude and air temperature, the latter being correlated with water temperature. In addition, a dysbiosis signature detected in gill microbiota was potentially associated with poor fish health status recorded in these disturbed environments. With those results, we hypothesized that rapid climate change and increasing anthropic activities in the Arctic might profoundly disturb Arctic char gill microbiota, affecting their survival.

Improving the technology for obtaining an ingredient with probiotic properties using a new complex proteolytic enzyme preparation

The development of technologies for producing bacterial concentrates and enzyme preparations using domestic microbial strains is an urgent task. The use of whey protein hydrolysates as components of nutrient media for probiotic bacteria consortia for the cultivation of lactic acid and bifidobacteria makes it possible to improve and develop innovative processes for obtaining bacterial concentrates with the required functional properties for the production of dietary supplements. A consortium of probiotic microorganisms (lactic acid and bifidobacteria) was created in the All-Russian Scientific Research Institute of Food Biotechnology as a starter culture for specialized dairy products. Using strain Aspergillus oryzae 21-154 LAP a new complex enzyme preparation with a laboratory name Protoorizin LAP has been obtained providing the extensive hydrolysis of protein substrates. The purpose of the research was to evaluate the possibility of using the new domestic proteolytic enzyme preparation Protoorizin LAP in preparing whey-based nutrient media for culturing a consortium of probiotic microorganisms to obtain bacterial concentrates. Material and methods. The object of the research was a symbiotic consortium, including lactic acid bacteria strains (Lactobacillus delbrueckii ssp. bulgaricus Д-16, Lactobacillus plantarum 578/25, Lactobacillus helveticus 842(D)-2, Lactococcus lactis subsp. lactis М-12, Streptococcus thermophilus В-92) and bifidobacteria (Bifidobacterium longum Б-2). Unclarified curd whey and whey protein concentrate were taken as the nutrient medium basis. The media were treated with β-galactosidase to reduce the lactose content. In order to hydrolyze proteins, the control culture medium was treated with commercial preparations: serine protease - Alcalase® 2.4 L and leucine aminopeptidase - Flavourzyme® 1000 L. In the experimental medium, two imported preparations were replaced with a laboratory sample of the enzyme preparation Protoorizin LAP. In the prepared nutrient media, the content of amine nitrogen, free amino acids and soluble protein was determined, and electrophoretic analysis of proteins and peptides was carried out. The consortium growth was monitored by the content of dry substances and reducing sugars, by active and titratable acidity, as well as by microscopy. The number of viable cells of lactic acid bacteria and bifidobacteria at the end of fermentation and in the resulting bacterial concentrates were determined by sieving on the appropriate selective agar media using an automatic colony counter. Results. The effectiveness of Protoorizin LAP in the hydrolysis of whey proteins significantly exceeded the result of the combined action of Alcalase® 2.4 L and Flavourzyme® 1000 L both in terms of reducing the undigested protein content, including immunogenic fractions, and in terms of the yield of soluble protein, amine nitrogen and amino acids. The nutrient media obtained using proteases ensured good growth and development of the probiotic consortium. Due to the high content of free amino acids, the dynamics of carbohydrate consumption, titratable acidity, and the number of viable cells were higher in the medium obtained using Protoorizin LAP than when using commercial preparations. At the same time, a high titer of probiotic strains and good cultural and morphological characteristics were obtained on all media. The experimental preparation Protoorizin LAP provided the increase in viability of bacterial cells after lyophilization. Conclusion. The technological method that include application of the new proteolytic preparation Protoorizin LAP in preparing nutrient media based on whey proteins was developed. The method can be used in the technology of producing bacterial concentrates at the stage of culturing of the created lactic acid and bifidobacteria consortium. The bacterial concentrate can be recommended as a recipe ingredient in the manufacture of dietary supplements or foods for special dietary uses containing probiotics.

The efficiency of bacterial cellulose biosynthesis from the amount of nitrogenous compounds in the nutrient medium

Bacterial cellulose (BC) is a promising material for technological and medical applications. The isolation of effective BC producers from natural symbiotic consortia is a promising direction in relation to industrial biotechnology of BC. The study consists in selecting the composition of the nutrient medium to increase the efficiency of the biosynthesis process of BC by cellulose-synthesizing bacteria isolated from the symbiotic consortium Medusomyces gisevii. Morphological features of isolated acetic acid bacteria have been determined - small rods, 0.8-1.2 microns in size with a rounded end, forming cream-colored colonies on agarized nutrient media, 2-7 mm in size with a characteristic luster. The composition of the nutrient medium RAE (AE) was determined, characterized by the maximum efficiency of BC biosynthesis (production of 4.63 g DM/l for 8 days; the degree of glucose conversion - 41.04%).

Evaluation of the adsorption capacity of glyphosate in a microbial cellulose composite

The objective of this project was to develop a composite based on microbial cellulose (CM), chitosan (Qs) and citric acid (AC) as a crosslinker at two different concentrations (4 and 6% w/v). The CM was obtained from the fermentation of fruit residues with a SCOBY (symbiotic consortium of bacteria and yeast). The composites were morphologically characterized by SEM and spectroscopy techniques (FTIR-ATR) as well as UV-VIS spectrophotometry with ninhydrin were used to evaluate the composite as an adsorbent for glyphosate in water; in the spectra obtained by FTIR, the representative vibrational bands of the functional groups belonging to chitosan and microbial cellulose were observed; for cellulose and chitosan composites with 4% citric acid in 1579 cm-1 , 1386 cm-1 , 1046 cm-1 and 853 cm-1 ; and for the 6% cellulose-chitosan-citric acid composite at 1573 cm-1 , 1380 cm-1 , 1056 cm-1 and 503 cm-1 , thus attributing cross linkage between the biopolymers. Post- adsorption FTIR-ATR analysis revealed significant changes possibly attributable to the adsorption of glyphosate in the cellulose composites. Further research is still being conducted to better understand this interaction and the involved mechanism; the goal is to comprehend how microbial cellulose can effectively adsorb glyphosate, which could have practical and efficient applications in the remediation of environments contaminated with this herbicide.

Sediment Microbial Fuel Cells with Algae-Assisted Cathodes for Electricity Generation and Bio-Treatment of Sewage Sludge

In this study, an algal–bacterial symbiotic consortium was integrated with the sediment microbial fuel cell (SMFC) to construct an algal–bacterial cathode SMFC (AC-SMFC) for excess sewage sludge treatment and electricity generation. A bacterial cathode SMFC (BC-SMFC) and a static settling system (SS-system) were used as controls. Electrochemical analysis confirmed that the algal–bacterial biofilm on the cathode improved electricity production. The maximum power density of AC-SMFC was 75.21 mW/m2, which was 65.70% higher than that of the BC-SMFC (45.39 mW/m2). After 60 days of treatment, AC-SMFC achieved much higher removal efficiencies of the total chemical oxygen demand (TCOD) (59.60%), suspended solids (SS) (62.42%), and volatile suspended solids (VSS) (71.44%) in the sediment, compared to BC-SMFC and the SS-system, exhibiting an effective degradation of the organic matter in the sediment sludge. Moreover, the lower concentration of total nitrogen (TN) and total phosphorus (TP) in the overlying water of AC-SMFC demonstrated that the algae on the cathode could inhibit the accumulation of nitrogen and phosphorus released from the sediments. The three-dimensional excitation–emission matrix (EEM) fluorescence spectroscopy revealed that the tryptophan protein and aromatic protein in the loosely bound extracellular polymeric substances (LB-EPS) of the sediment sludge in the AC-SMFC were significantly decreased. Additionally, the abundance of functional microbiota in the AC-SMFC increased, such as Trichococcus, Alphaproteobacteria, and Clostridia, which contributed to electricity generation and sludge degradation. The combined application of microalgae and the SMFC provided a promising approach for excess sludge reduction and energy recovery.

Antifungal activity of clove basil (Ocimum gratissimum L.) beverage fermented with kombucha culture

Fungi are associated with several diseases in humans, however these diseases have been neglected over the years. Fungal infections are estimated to cause more than 1.5 million deaths annually. In addition, recent studies have revealed the presence of pathogens resistant to antifungal drugs available for treatment. In view of this scenario, it is necessary to invest in research aimed at the discovery and development of new antifungal therapies. An important aspect to be considered is the antimicrobial activity attributed to fermented beverages, such as kombucha, which is obtained from the fermentation of an infusion of plant parts by a symbiotic consortium of bacteria and yeast known as SCOBY (Symbiotic Culture of Bacteria and Yeast). In this context, the aim of this work was to elaborate a fermented beverage based on clove basil (Ocimum gratissimum L.) (CBK) and to evaluate its antimicrobial activity against fungi Candida albicans, Candida auris, Candida glabrata, Candida tropicalis and Cryptococcus neoformans. CBK has presented pH values within the required legislation for kombucha, demonstrating quality and safety standards in the fermentation process. As for antimicrobial analysis, CBK fermented for 15 days showed antifungal effect on all tested strains, however, the fungicidal effect was only verified against C. albicans, C. auris e C. neoformans. Thus, this study contributes to the description of a new source of antifungal substances and opens perspectives for future research on the biotransformation processes of chemical compounds during fermentation procedures.

Variation of bacterial community assembly over developmental stages and midgut of Dermanyssus gallinae.

Bacterial microbiota play an important role in the fitness of arthropods, but the bacterial microflora in the parasitic mite Dermanyssus gallinae is only partially explored; there are gaps in our understanding of the microbiota localization and in our knowledge of microbial community assembly. In this work, we have visualized, quantified the abundance, and determined the diversity of bacterial occupancy, not only across developmental stages of D. gallinae, but also in the midgut of micro-dissected female D. gallinae mites. We explored community assembly and the presence of keystone taxa, as well as predicted metabolic functions in the microbiome of the mite. The diversity of the microbiota and the complexity of co-occurrence networks decreased with the progression of the life cycle. However, several bacterial taxa were present in all samples examined, indicating a core symbiotic consortium of bacteria. The relatively higher bacterial abundance in adult females, specifically in their midguts, implicates a function linked to the biology of D. gallinae mites. If such an association proves to be important, the bacterial microflora qualifies itself as an acaricidal or vaccine target against this troublesome pest.

Algae-mediated bioremediation of ciprofloxacin through a symbiotic microalgae-bacteria consortium

The ciprofloxacin treating via microalga and its microalgae-bacteria consortium was investigated for discussing the potential application of microalgae-mediated bioremediation. As results, the maximum removal efficiency of ciprofloxacin by pure microalgae and the consortium was 87.5 ± 3.5 % (5 mg/L) and 96.1 ± 0.07 % (40 mg/L), respectively. The consortium enhanced the degradation rate to 0.81 d−1 compared with the pure microalgae (0.27 d−1). To reveal the symbiotic mechanism, extracellular polymeric substances, pigments contents, antioxidant enzymes and symbiotic bacterial community were analyzed. The malondialdehyde content in the pure microalgae (1622.6 ± 38.7 nmol/mg protein) was higher than that in the consortium (298.34 ± 2.4 nmol/mg protein), and there were obvious chlorophyll b accumulations (approximately 90 %) in consortium. In addition, the symbiotic bacteria had a positive effect on microalgal secretion of fulvic acid-type components. As mechanism, symbiotic bacteria improved ciprofloxacin biodegradation by reducing cell damage and secreting fulvic acid. The presence of Phycisphaeraceae and Rhizobiaceae, nitrogen fixation bacteria, in the consortium suggest that improvement of ciprofloxacin biodegradation might be associated with nitrogen co-metabolism as well. Collectively, this work elucidates the mechanism of enhancing elimination of ciprofloxacin via microalgae-bacteria consortium and accelerates development of microalgae-mediated aquaculture tailwater bioremediation.

Medusomyces gisevii L.: cultivation, composition, and application

Tea fungus (Medusomyces gisevii L.) is a natural symbiotic consortium of yeast-like fungi and bacteria. Scientific literature provides a lot of information about the consortium, but it is largely fragmentary. We aimed to review and systematize the information on the research topic.
 We studied scientific publications, conference proceedings, intellectual property, regulatory documents, and Internet resources on the M. gisevii consortium using Scopus, Web of Science, e.LIBRARY.RU, and Google Academy. The methods applied included registration, grouping, classification, comparative analysis, and generalization.
 We described the origin and composition of tea fungus, specifying the microorganisms that make up its symbiotic community depending on the place of origin. Then, we reviewed the stages of fermentation and cultivation conditions in various nutrient media and presented the composition of the culture liquid. Finally, we analyzed the antimicrobial effect of M. gisevii on a number of microorganisms and delineated some practical uses of the fungus.
 The data presented in this article can be used to analyze or develop new methods for the cultivation and application of M. gisevii. We specified some possibilities for using not only the culture liquid but also the fruit body of the fungus in various industries.

Sustained detoxification of 1,2-dichloroethane to ethylene by a symbiotic consortium containing Dehalococcoides species

1,2-Dichloroethane (1,2-DCA) is a ubiquitous volatile halogenated organic pollutant in groundwater and soil, which poses a serious threat to the ecosystem and human health. Microbial reductive dechlorination has been recognized as an environmentally-friendly strategy for the remediation of sites contaminated with 1,2-DCA. In this study, we obtained an anaerobic microbiota derived from 1,2-DCA contaminated groundwater, which was able to sustainably convert 1,2-DCA into non-toxic ethylene with an average dechlorination rate of 30.70 ± 11.06 μM d−1 (N = 6). The microbial community profile demonstrated that the relative abundance of Dehalococcoides species increased from 0.53 ± 0.08% to 44.68 ± 3.61% in parallel with the dechlorination of 1,2-DCA. Quantitative PCR results showed that the Dehalococcoides species 16S rRNA gene increased from 2.40 ± 1.71 × 108 copies∙mL−1 culture to 4.07 ± 2.45 × 108 copies∙mL−1 culture after dechlorinating 110.69 ± 30.61 μmol of 1,2-DCA with a growth yield of 1.55 ± 0.93 × 108 cells per μmol Cl− released (N = 6), suggesting that Dehalococcoides species used 1,2-DCA for organohalide respiration to maintain cell growth. Notably, the relative abundances of Methanobacterium sp. (p = 0.0618) and Desulfovibrio sp. (p = 0.0001995) also increased significantly during the dechlorination of 1,2-DCA and were clustered in the same module with Dehalococcoides species in the co-occurrence network. These results hinted that Dehalococcoides species, the obligate organohalide-respiring bacterium, exhibited potential symbiotic relationships with Methanobacterium and Desulfovibrio species. This study illustrates the importance of microbial interactions within functional microbiota and provides a promising microbial resource for in situ bioremediation in sites contaminated with 1,2-DCA.

Biochemical and Genomic Characterization of Two New Strains of Lacticaseibacillus paracasei Isolated from the Traditional Corn-Based Beverage of South Africa, Mahewu, and Their Comparison with Strains Isolated from Kefir Grains.

Lacticaseibacillus paracasei (formerly Lactobacillus paracasei) is a nomadic lactic acid bacterium (LAB) that inhabits a wide variety of ecological niches, from fermented foodstuffs to host-associated microenvironments. Many of the isolated L. paracasei strains have been used as single-strain probiotics or as part of a symbiotic consortium within formulations. The present study contributes to the exploration of different strains of L. paracasei derived from non-conventional isolation sources-the South African traditional fermented drink mahewu (strains MA2 and MA3) and kefir grains (strains KF1 and ABK). The performed microbiological, biochemical and genomic comparative analyses of the studied strains demonstrated correlation between properties of the strains and their isolation source, which suggests the presence of at least partial strain adaptation to the isolation environments. Additionally, for the studied strains, antagonistic activities against common pathogens and against each other were observed, and the ability to release bioactive peptides with antioxidant and angiotensin I-converting enzyme inhibitory (ACE-I) properties during milk fermentation was investigated. The obtained results may be useful for a deeper understanding of the nomadic lifestyle of L. paracasei and for the development of new starter cultures and probiotic preparations based on this LAB in the future.

Fermented Beet Juice with a Highly Active Symbiotic Consortium of Probiotic Lactobacillus Strains as a Specialized Product for Nutrition of People Working and Living in Extreme Conditions

The consortium of symbiotic strains of lactobacilli Lactobacillus plantarum MDIIE 2165 and Lactobacillus rhamnosus MDIIE 2166, deposited in the All-Russian Collection of Microorganisms (IBFM RAS), is the most suitable starter for obtaining a fermented beet juice (FBJ). These innovative probiotic lactobacilli ensure a deep processing of raw materials and allow a specialized food product with high organoleptic characteristics, biological value and adaptogenic properties to be obtained. FBJ can be used as a specialized nutrition product to improve the performance of athletes and people working and living in extreme conditions, as well as to prolong the professional longevity of the population.

The Impact of Kefir on Epidermal Water Homeostasis in Healthy Human Skin.

Kefir, a symbiotic consortium of diverse bacteria and yeasts, is one of the most popular probiotic foods on the market. Its consumption has been referred to as beneficial in human skin health, namely in the reinforcement of skin’s barrier function. This benefit likely results from the productive activity of lactic acid bacteria during kefir fermentation. Lactic acid is naturally present in the skin, and actively contributes to epidermal water dynamics and “barrier.” Few studies have been conducted regarding the impact of probiotic consumption in human epidermal water homeostasis. Therefore, this study was designed to explore the impact of the regular consumption of kefir on the skin water dynamics in a group of participants with healthy skin. Participants (n = 27) were healthy female volunteers from whom twelve consumed 100 mL of kefir every day for eight weeks as part of their diet. The remaining (untreated) participants served as the control group. Epidermal water balance was assessed by measuring transepidermal water loss (TEWL) and stratum corneum (SC) hydration on three different occasions—at baseline (T0), after four weeks (T4) and after eight weeks (T8) of interventive kefir consumption. Our study revealed a significant reduction in TEWL (p = 0.043) in the kefir group after eight weeks of regular consumption. In the same period, no differences were found for TEWL in the control group (p = 0.997). Regarding hydration, skin dryness was progressive in the control group, with a significant reduction in SC hydration (p = 0.002) at T8 in comparison to T0. In the kefir group, SC hydration was preserved between T0 and T8 (p = 0.997), which we believe to be related to epidermal “barrier” reinforcement. Our study seems to confirm that the regular consumption of kefir does improve cutaneous water balance even in healthy skin.

Temperature Affects Antagonism Among Coral-Associated Bacteria

Reef-building corals are invertebrate animals that associate with diverse microorganisms, including Symbiodiniaceae, bacteria, fungi, and archaea. This symbiotic consortium, called the holobiont, is a dynamic system and rapidly responds to environmental temperatures. At present, the effects of temperature on bacteria-bacteria interactions in the coral-associated bacterial community are not clear. Antagonism is considered one of the potential structuring forces in coral microbial communities. Here, we examined the antagonistic interactions among 32 coral-associated bacteria and the physiological and biochemical characteristics of these isolates at different temperatures. The results showed that the antagonism breadth (i.e. the total number of antagonistic interactions) increased but antagonism intensity (i.e. the size of the inhibition zone) decreased at 32°C. The antagonistic interaction network was nested and sender-determined both at 25°C and 32°C, suggesting that the competition networks of coral-associated bacteria were more influenced by the antagonist strains than sensitive strains. Furthermore, we found that the elevated temperature increased the complexity of the antagonistic network. By evaluating the correlations between antagonism and the phylogenetic and phenotypic distances, we demonstrated that the antagonism probability correlated with the phylogenetic distance rather than phenotypic distance. Moreover, the antagonist strains have a wider metabolic niche space, i.e., grew on more carbon sources, than the antagonized strains at 25°C, while there was no difference at 32°C, suggesting the trade-off between antagonism and resource exploitation shifted in the antagonistic interactions under the higher temperature. These findings will be helpful for understanding the bacterial interactions in coral holobionts and the assembly of bacterial community in altered environments, especially under heat stress.

Machine learning prediction of SCOBY cellulose yield from Kombucha tea fermentation

The commercialization of by-product of Kombucha SCOBY (Symbiotic consortium of bacteria and yeast) could be the sustainable way of transforming waste into value-added products. This study aims at developing a robust machine learning model for the prediction of SCOBY yield. Concentrations of tea, sucrose, SCOBY, inoculum, pH, temperature, and fermentation time were the input parameters considered. The robustness of the models was studied using correlation coefficient and root mean square error. Among the algorithms studied, XGB (eXtreme Gradient Boosting) was the most resilient model with high accuracy. By hyperparameter tuning and k-fold cross-validations, the model performance was improved to attain an R2 value of 0.9048. The relationship between variables was depicted as Pair plot and Pearson correlation matrix. Fermentation temperature was the most influential parameter affecting SCOBY yield. Shapley additive explanations dependence plots and summary plot provided insights on the combined effects of input parameters on the SCOBY yield.

An overview of antimicrobial properties of kombucha.

Kombucha is a traditional beverage of Manchurian origin, typically made by fermenting sugared black or green tea with the symbiotic consortium of bacteria and yeast (SCOBY). The beverage has gained increasing popularity in recent years, mainly due to its heralded health benefits. The fermentation process of kombucha also results in the production of various bioactive compounds with antimicrobial potential, making it a promising candidate in the exploration of alternative sources of antimicrobial agents, and may be helpful in combating the rising threat of antibiotic resistance. Literature survey performed on Web of Science, Scopus, and PubMed revealed the extensive research that has firmly established the antimicrobial activity of kombucha against a broad spectrum of bacteria and fungi. This activity could be attributed to the synergistic activities of the microbial species in the kombucha microbiota that led to the synthesis of compounds with antimicrobial properties such as acetic acid and various polyphenols. However, research thus far only involved screening for the antimicrobial activity of kombucha. Therefore, there is still a research gap about the molecular mechanism of the kombucha reaction against specific pathogens and its influence on human health upon consumption. Future research may focus on investigating this aspect. Further characterization of the biological activity of the microbial community in kombucha may also facilitate the discovery of novel antimicrobial compounds, such as bacteriocins produced by the microorganisms.