Root-associated endophytic bacterial community composition and structure of three medicinal licorices and their changes with the growing year.

BACKGROUND: The dried roots and rhizomes of medicinal licorices are widely used worldwide as a traditional medicinal herb, which are mainly attributed to a variety of bioactive compounds that can be extracted from licorice root. Endophytes and plants form a symbiotic relationship, which is an important source of host secondary metabolites. RESULTS: In this study, we used high-throughput sequencing technology and high-performance liquid chromatography to explore the composition and structure of the endophytic bacterial community and the content of bioactive compounds (glycyrrhizic acid, liquiritin and total flavonoids) in different species of medicinal licorices (Glycyrrhiza uralensis, Glycyrrhiza glabra, and Glycyrrhiza inflata) and in different planting years (1-3 years). Our results showed that the contents of the bioactive compounds in the roots of medicinal licorices were not affected by the species, but were significantly affected by the main effect growing year (1-3) (P < 0.05), and with a trend of stable increase in the contents observed with each growing year. In 27 samples, a total of 1,979,531 effective sequences were obtained after quality control, and 2432 effective operational taxonomic units (OTUs) were obtained at 97% identity. The phylum Proteobacteria, Actinobacteria, Bacteroidetes and Firmicutes, and the genera unified-Rhizobiaceae, Pseudomonas, Novosphingobium, and Pantoea were significantly dominant in the 27 samples. Distance-based redundancy analysis (db-RDA) showed that the content of total flavonoids explained the differences in composition and distribution of endophytic bacterial communities in roots of cultivated medicinal liquorices to the greatest extent. Total soil salt was the most important factor that significantly affected the endophytic bacterial community in soil factors, followed by ammonium nitrogen and nitrate nitrogen. Among the leaf nutrition factors, leaf water content had the most significant effect on the endophytic bacterial community, followed by total phosphorus and total potassium. CONCLUSIONS: This study not only provides information on the composition and distribution of endophytic bacteria in the roots of medicinal licorices, but also reveals the influence of abiotic factors on the community of endophytic bacteria and bioactive compounds, which provides a reference for improving the quality of licorice.

Consumption of Wild Rice (Zizania latifolia) Prevents Metabolic Associated Fatty Liver Disease through the Modulation of the Gut Microbiota in Mice Model.

Metabolic associated fatty liver disease (MAFLD) due to excess weight and obesity threatens public health worldwide. Gut microbiota dysbiosis contributes to obesity and related diseases. The cholesterol-lowering, anti-inflammatory, and antioxidant effects of wild rice have been reported in several studies; however, whether it has beneficial effects on the gut microbiota is unknown. Here, we show that wild rice reduces body weight, liver steatosis, and low-grade inflammation, and improves insulin resistance in high-fat diet (HFD)-fed mice. High-throughput 16S rRNA pyrosequencing demonstrated that wild rice treatment significantly changed the gut microbiota composition in mice fed an HFD. The richness and diversity of the gut microbiota were notably decreased upon wild rice consumption. Compared with a normal chow diet (NCD), HFD feeding altered 117 operational taxonomic units (OTUs), and wild rice supplementation reversed 90 OTUs to the configuration in the NCD group. Overall, our results suggest that wild rice may be used as a probiotic agent to reverse HFD-induced MAFLD through the modulation of the gut microbiota.

Steel slag amendment impacts on soil microbial communities and activities of rice (Oryza sativa L.).

With the increase in iron/steel production, the higher volume of by-products (slag) generated necessitates its efficient recycling. Because the Linz-Donawitz (LD) slag is rich in silicon (Si) and other fertilizer components, we aim to evaluate the impact of the LD slag amendment on soil quality (by measuring soil physicochemical and biological properties), plant nutrient uptake, and strengthens correlations between nutrient uptake and soil bacterial communities. We used 16 S rRNA illumine sequencing to study soil bacterial community and APIZYM assay to study soil enzymes involved in C, N, and P cycling. The LD slag was applied at 2 Mg ha-1 to Japonica and Indica rice cultivated under flooded conditions. The LD slag amendment significantly improved soil pH, plant photosynthesis, soil nutrient availability, and the crop yield, irrespective of cultivars. It significantly increased N, P, and Si uptake of rice straw. The slag amendment enhanced soil microbial biomass, soil enzyme activities and enriched certain bacterial taxa featuring copiotrophic lifestyles and having the potential role for ecosystem services provided to the benefit of the plant. The study evidenced that the short-term LD slag amendment in rice cropping systems is useful to improve soil physicochemical and biological status, and the crop yield.

Synergistic Effect of Rhamnolipids and Inoculation on the Bioremediation of Petroleum-Contaminated Soils by Bacterial Consortia.

Crude oil is a serious soil pollutant, requiring large-scale remediation efforts. Bacterial consortia in combination with rhamnolipids can be an effective bioremediation method. However, the underlying mechanisms and associated changes in soil bacterial composition remain uncharacterized. Therefore, this study sought to evaluate the effectiveness of rhamnolipids in petroleum hydrocarbon removal, and the associated bacterial community dynamics during bioremediation of petroleum-contaminated soils. Contaminated soils were subjected to natural attenuation, bioremediation with rhamnolipids, bioremediation with bacterial consortia, or bioremediation with bacterial consortia supplemented with rhamnolipids (BMR). High-throughput sequencing of bacterial sample partial 16S rRNA sequences was performed. Additionally, the n-alkanes and aromatic fractions were analyzed by gas chromatography-mass spectroscopy. The results showed that rhamnolipid supplementation increased the rate and extent of total petroleum hydrocarbon biodegradation to a maximum of 81% within 35 days. Further, phylogenetic analysis revealed that the bacterial community was composed of 14 phylotypes (similarity level = 97%). Actinobacteria and Proteobacteria were the two core phyla in all samples, accounting for 63-89%, but Proteobacteria was the most dominant phylum in the BMR sample (~ 53%). Among the top 20 genera, Pseudomonas, Pseudoxanthomonas, Cavicella, Mycobacterium, Rhizobium, and Acinetobacter were more abundant in BMR samples compared to other samples. Predicted functional profiles revealed that rhamnolipid addition also induced changes in gene abundance related to hydrocarbon metabolic pathways. This study provided comprehensive insights into the synergistic effect of rhamnolipids and bacterial consortia for altering bacterial populations and specific functional traits, which may serve to improve bacteria-mediated petroleum hydrocarbon biodegradation in contaminated soils.

The roles of free ammonia (FA) in biological wastewater treatment processes: A review.

Free ammonia (FA) can pose inhibitory and/or biocidal effects on a variety of microorganisms involved in different biological wastewater treatment process, which is widely presented in wastewater treatment plants (WWTPs) due to the high levels of ammonium in the systems. This review article gives the up-to-date status on several essential roles of FA in biological wastewater treatment processes: the impacts of FA, mechanisms of FA roles, modeling of FA impacts, and implications of FA for wastewater treatment. Specifically, the impacts of FA on both wastewater and sludge treatment lines were firstly summarized, including nitrification, denitrification, anaerobic ammonium oxidation (Anammox), enhanced biological phosphorus removal and anaerobic processes. The involved mechanisms were then analyzed, which indicated FA inhibition can slow specific microbial activities or even reconfigure the microbial community structure, likely due to negative impacts of FA on intracellular pH, specific enzymes and extracellular polymeric substances (EPS), thus causing cell inactivation/lysis. Mathematical models describing the impact of FA on both wastewater and sludge treatment processes were also explored to facilitate process optimization. Finally, the key implications of FA were identified, that is FA can be leveraged to substantially enhance the biodegradability of secondary sludge, which would further improve biological nutrient removal and enhance renewable energy production.

Microbial communities of polluted sub-surface marine sediments.

Microbial communities of coastal marine sediment play a key role in degradation of petroleum contaminants. Here the bacterial and archaeal communities of sub-surface sediments (5-10 cm) of the chronically polluted Priolo Bay (eastern coast of Sicily, Italy), contaminated mainly by n-alkanes and biodegraded/weathered oils, were characterized by cultural and molecular approaches. 16S-PCR-DGGE analysis at six stations, revealed that bacterial communities are highly divergent and display lower phylogenetic diversity than the surface sediment; sub-surface communities respond to oil supplementation in microcosms with a significant reduction in biodiversity and a shift in composition; they retain high biodegradation capacities and host hydrocarbon (HC) degraders that were isolated and identified. HC-degrading Alfa, Gamma and Epsilon proteobacteria together with Clostridia and Archaea are a common feature of sub-surface communities. These assemblages show similarities with that of subsurface petroleum reservoirs also characterized by the presence of biodegraded and weathered oils where anaerobic or microaerophilic syntrophic HC metabolism has been proposed.

Structural and functional measures of marine microbial communities: An experiment to assess implications for oil spill management.

Microbial communities are ecologically important in aquatic environments and impacts on microbes have the potential to affect a number of functional processes. We have amended seawater with a crude oil and assessed changes in species composition as well as a measure of functional diversity (the ability of the community to utilise different carbon sources) and the community level metabolic signature. We found that there was a degree of functional redundancy in the community we tested. Oiled assemblages became less diverse and more dominated by specialist hydrocarbon degraders, carbon source utilisation increased initially but there was no change in metabolic signature in this small scale laboratory experiment. This study supports the decision framework around management of oil spills. This package of methods has the potential to be used in the testing and selection of new dispersants for use in oil spill response.

Genomic identification of microbial species adhering to maxillofacial prostheses and susceptibility to different hygiene protocols.

This study investigated the microbial colonization of maxillofacial prostheses and support tissues using the Checkerboard DNA-DNA hybridization method, and the efficacy of 0.12% chlorhexidine gluconate, 10% Ricinus communis solutions, or brushing, on colony forming unit (CFU) reduction in monospecies biofilms (Candida glabrata, Staphylococcus aureus, Streptococcus mutans, Escherichia coli, Enterococcus faecalis, and Pseudomonas aeruginosa) formed on two silicones (MDX 4-4210 and Bio-Skin). Biofilm was harvested from 43 maxillofacial prosthesis wearers for detection of 38 species of microorganisms. The CFU counts of the six above mentioned species were recorded after using the hygiene protocols. All 38 investigated species were identified in prostheses and tissues, with a higher prevalence in the prostheses. 0.12% chlorhexidine gluconate immersion showed the greatest antimicrobial effectiveness, followed by mechanical brushing protocols. MDX 4-4210 silicone produced lower CFU counts than Bio-Skin.

Effects of uranium concentration on microbial community structure and functional potential.

Located in the Northern Territory of Australia, Ranger uranium mine is directly adjacent to the UNESCO World Heritage listed Kakadu National Park, with rehabilitation targets needed to ensure the site can be incorporated into the park following the mine's closure in 2026. This study aimed to understand the impact of uranium concentration on microbial communities, in order to identify and describe potential breakpoints in microbial ecosystem services. This is the first study to report in situ deployment of uranium-spiked sediments along a concentration gradient (0-4000 mg U kg-1 ), with the study design maximising the advantages of both field surveys and laboratory manipulative studies. Changes to microbial communities were characterised through the use of amplicon and shotgun metagenomic next-generation sequencing. Significant changes to taxonomic and functional community assembly occurred at a concentration of 1500 mg U kg-1 sediment and above. At uranium concentrations of ≥ 1500 mg U kg-1 , genes associated with methanogenic consortia and processes increased in relative abundance, while numerous significant changes were also seen in the relative abundances of genes involved in nitrogen cycling. Such alterations in carbon and nitrogen cycling pathways suggest that taxonomic and functional changes to microbial communities may result in changes in ecosystem processes and resilience.

Inorganic phosphorus fertilizer ameliorates maize growth by reducing metal uptake, improving soil enzyme activity and microbial community structure.

Recently, several studies have showed that both organic and inorganic fertilizers are effective in immobilizing heavy metals at low cost, in comparison to other remediation strategies for heavy metal-contaminated farmlands. A pot trial was conducted in this study to examine the effects of inorganic P fertilizer and organic fertilizer, in single application or in combination, on growth of maize, heavy metal availabilities, enzyme activities, and microbial community structure in metal-contaminated soils from an electronic waste recycling region. Results showed that biomass of maize shoot and root from the inorganic P fertilizer treatments were respectively 17.8 and 10.0 folds higher than the un-amended treatments (CK), while the biomass in the organic fertilizer treatments was only comparable to the CK. In addition, there were decreases of 85.0% in Cd, 74.3% in Pb, 66.3% in Cu, and 91.9% in Zn concentrations in the roots of maize grown in inorganic P fertilizer amended soil. Consistently, urease and catalase activities in the inorganic P fertilizer amended soil were 3.3 and 2.0 times higher than the CK, whereas no enhancement was observed in the organic fertilizer amended soil. Moreover, microbial community structure was improved by the application of inorganic P fertilizer, but not by organic fertilizer; the beneficial microbial groups such as Kaistobacter and Koribacter were most frequently detected in the inorganic P fertilizer amended soil. The negligible effect from the organic fertilizer might be ascribed to the decreased pH value in soils. The results suggest that the application of inorganic P fertilizer (or in combination with organic fertilizer) might be a promising strategy for the remediation of heavy metals contaminated soils in electronic waste recycling region.

Microbial composition and diversity are associated with plant performance: a case study on long-term fertilization effect on wheat growth in an Ultisol.

The association between microbial communities and plant growth in long-term fertilization system has not been fully studied. In the present study, impacts of long-term fertilization have been determined on the size and activity of soil microbial communities and wheat performance in a red soil (Ultisol) collected from Qiyang Experimental Station, China. For this, different microbial communities originating from long-term fertilized pig manure (M), mineral fertilizer (NPK), pig manure plus mineral fertilizer (MNPK), and no fertilizer (CK) were used as inocula for the Ultisol tested. Changes in total bacterial and fungal community composition and structures using Ion Torrent sequencing were determined. The results show that the biomass of wheat was significantly higher in both sterilized soil inoculated with NPK (SNPK) and sterilized soil inoculated with MNPK (SMNPK) treatments than in other treatments (P < 0.05). The activities of ß-1,4-N-acetylglucosaminidase (NAG) and cellobiohydrolase (CBH) were significantly correlated with wheat biomass. Among the microbial communities, the largest Ascomycota phylum in soils was negatively correlated with ß-1,4-glucosidase (ßG) (P < 0.05). The phylum Basidiomycota was negatively correlated with plant biomass (PB) and tillers per plant (TI) (P < 0.05). Nonmetric multidimensional scaling analysis shows that fungal community was strongly correlated with long-term fertilization strategy, while the bacterial community was strongly correlated with ß-1,4-N-acetylglucosaminidase activity. According to the Mantel test, the growth of wheat was affected by fungal community. Taken together, microbial composition and diversity in soils could be a good player in predicting soil fertility and consequently plant growth.

Influence of straw incorporation with and without straw decomposer on soil bacterial community structure and function in a rice-wheat cropping system.

To study the influence of straw incorporation with and without straw decomposer on bacterial community structure and biological traits, a 3-year field experiments, including four treatments: control without fertilizer (CK), chemical fertilizer (NPK), chemical fertilizer plus 7500 kg ha-1 straw incorporation (NPKS), and chemical fertilizer plus 7500 kg ha-1 straw incorporation and 300 kg ha-1 straw decomposer (NPKSD), were performed in a rice-wheat cropping system in Changshu (CS) and Jintan (JT) city, respectively. Soil samples were taken right after wheat (June) and rice (October) harvest in both sites, respectively. The NPKS and NPKSD treatments consistently increased crop yields, cellulase activity, and bacterial abundance in both sampling times and sites. Moreover, the NPKS and NPKSD treatments altered soil bacterial community structure, particularly in the wheat harvest soils in both sites, separating from the CK and NPK treatments. In the rice harvest soils, both NPKS and NPKSD treatments had no considerable impacts on bacterial communities in CS, whereas the NPKSD treatment significantly shaped bacterial communities compared to the other treatments in JT. These practices also significantly shifted the bacterial composition of unique operational taxonomic units (OTUs) rather than shared OTUs. The relative abundances of copiotrophic bacteria (Proteobacteria, Betaproteobacteria, and Actinobacteria) were positively correlated with soil total N, available N, and available P. Taken together, these results indicate that application of straw incorporation with and without straw decomposer could particularly stimulate the copiotrophic bacteria, enhance the soil biological activity, and thus, contribute to the soil productivity and sustainability in agro-ecosystems.

The impact of wastewater treatment effluent on microbial biomasses and diversities in coastal sediment microcosms of Hangzhou Bay.

Disposal of wastewater treatment plant (WWTP) effluent into sea, a typical anthropogenic disturbance, may influence many environmental factors and change the coastal microbial community structure. In this study, by setting up coastal sediment microcosms perturbed by WWTP effluent, the changes of microbial community structure under different degree of disturbances were investigated. Quantitative PCR (qPCR) and terminal restriction fragment length polymorphism (T-RFLP) were used to analyzed the biomass and biodiversity. High throughput sequencing analysis was used to identify the classification of the microorganisms. Our study suggested that low ratio of WWTP effluent may stimulate dominant species, which increase the biomass but decrease the biodiversity; while high ratio of WWTP effluent may depress all species, which decrease the biomass but increase the biodiversity. In other words, the impact was dose-dependent. The changes of microbial community structure may provide a metric for water environmental assessment and pollution control.

Magnetic Fe3O4 nanoparticles induced effects on performance and microbial community of activated sludge from a sequencing batch reactor under long-term exposure.

The performance and microbial community of activated sludge from a sequencing batch reactor (SBR) were investigated under long-term exposure of magnetic Fe3O4 nanoparticles (Fe3O4 NPs). The COD removal showed a slight decrease at 5-60mg/L Fe3O4 NPs compared to 0mg/L Fe3O4 NPs, whereas the NH4+-N removal had no obvious variation at 0-60mg/L Fe3O4 NPs. It was found that 10-60mg/L Fe3O4 NPs improved the denitrification process and phosphorus removal of activated sludge. The microbial enzymatic activities of activated sludge could be affected by Fe3O4 NPs, which had similar variation trends to the nitrogen and phosphorus removal rates of activated sludge. The reactive oxygen species (ROS) production and lactate dehydrogenase (LDH) release demonstrated that Fe3O4 NPs led to the toxicity to activated sludge and destroyed the integrity of microbial cytomembrane. High throughput sequencing indicated that Fe3O4 NPs could obviously affect the microbial richness and diversity of activated sludge.

Understanding the performance of microbial community induced by ZnO nanoparticles in enhanced biological phosphorus removal system and its recoverability.

In this study, the impacts of ZnO Nanoparticles (NPs) on the microbial community in enhanced biological phosphorus removal (EBPR) system and its recoverability were investigated. High-throughput sequencing was applied to study the microbial community shift. Results show that the species richness in the EBPR system was reduced under the condition of ZnO NPs with high concentration (above 6mg/L). Evolution analysis suggests that higher concentration ZnO NPs induced more microbial community shift. According to the analysis on genus level, Competibacter was more impressionable than Accumulibacter after exposure to 2mg/L ZnO NPs. Nonetheless, this phenomenon could not be found as the concentration of ZnO NPs got higher (above 6mg/L). Accumulibacter could reach to the initial level after recover for 20days, whereas Competibacter could not recover even when the concentration of ZnO NPs was only 2mg/L. Interestingly, although the phosphorus removal (P-removal) process was re-achieved, the microbial community in reactors was irreversible.

Combined Treatment on the Inactivation of Naturally Existing Bacteria and Escherichia coli O157:H7 Inoculated on Fresh-Cut Kale.

An aqueous chlorine dioxide (ClO2) treatment combined with highly activated calcium oxide (CaO) and mild heat was tested for inactivating naturally existing bacteria and Escherichia coli O157:H7 inoculated on fresh-cut kale. Kale samples were treated with different concentrations of ClO2 (10, 30, and 50 ppm), CaO (0.01%, 0.05%, 0.1%, and 0.2%), and mild heat (25°C, 45°C, 55°C, and 65°C) as well with combinations of 30 or 50 ppm ClO2 and 0.2% CaO at 55°C for 3 min. An increasing concentration of ClO2 and CaO significantly reduced the microbialpopulation compared with the control. In addition, mild heating at 55°C elicited greater microbial reduction than the other temperatures. A combined treatment of 50 ppm ClO2 and 0.2% CaO at 55°C reduced the population of naturally existing bacteria on kale by 3.10 logcolony forming units (CFU)/g, and the counts of E. coli O157:H7 were below the detection limit (1 log CFU/g). In addition, no significant differences in the Hunter color values were evident in any treatment during storage. Therefore, a combined treatment of ClO2 and active CaO at 55°C can be an effective sanitizing method to improve the microbiological safety of fresh-cut kale without affecting its quality.

Effect of nickel on the flocculability, settleability, and dewaterability of activated sludge.

Short-term and long-term effects of nickel (Ni) (0.1-10mg/L) on the physicochemical properties of activated sludge, including the flocculability, settleability, and dewaterability, were investigated. It was found that these properties were unaffected after short-term exposure (1day) to Ni(II) even at the level of 10mg/L. After long-term exposure (60days) to 1 and 10mg/L of Ni(II), however, the sludge flocculability has seriously deteriorated, while the settleability, and dewaterability became gradually better than the control. The mechanism studies revealed that long-term exposure to Ni(II) resulted in the decrease of protein content in extracellular polymeric substances (EPS) and the damage to EPS structures. Although Ni(II) did not bring any adverse effect on the cell membrane, the relative hydrophobicity of activated sludge was significantly decreased. The negative effects on the flocculability and phosphorus removal performance of activated sludge could be completely eliminated by adding the chelator such as EDTA and citrate.

Performance evaluation, microbial enzymatic activity and microbial community of a sequencing batch reactor under long-term exposure to cerium dioxide nanoparticles.

The performance, microbial enzymatic activity and microbial community of a sequencing batch reactor (SBR) were investigated under long-term exposure to cerium dioxide nanoparticles (CeO2 NPs). The COD removal kept a stable value at 0-5mg/L CeO2 NPs and then decreased at 10-60mg/L CeO2 NPs. The NH4(+)-N removal had no obvious changes at 0-30mg/L CeO2 NPs, and a minor decrease appeared at 60mg/L CeO2 NPs. Compared to 0mg/L CeO2 NPs, the phosphorus removal showed a decrease at 2mg/L CeO2 NPs and slightly increased at 5-60mg/L CeO2 NPs. The nitrogen and phosphorus removal rates had similar variation trends to the microbial enzymatic activities. The variations of reactive oxygen species (ROS) and lactate dehydrogenase (LDH) indicated that high CeO2 NPs concentration could result in the biotoxicity to activated sludge. The presence of CeO2 NPs had obvious effect on the microbial richness and diversity of activated sludge.

Insights into the biodegradation of weathered hydrocarbons in contaminated soils by bioaugmentation and nutrient stimulation.

The potential for biotransformation of weathered hydrocarbon residues in soils collected from two commercial oil refinery sites (Soil A and B) was studied in microcosm experiments. Soil A has previously been subjected to on-site bioremediation and it was believed that no further degradation was possible while soil B has not been subjected to any treatment. A number of amendment strategies including bioaugmentation with hydrocarbon degrader, biostimulation with nutrients and soil grinding, were applied to the microcosms as putative biodegradation improvement strategies. The hydrocarbon concentrations in each amendment group were monitored throughout 112 days incubation. Microcosms treated with biostimulation (BS) and biostimulation/bioaugmentation (BS + BA) showed the most significant reductions in the aliphatic and aromatic hydrocarbon fractions. However, soil grinding was shown to reduce the effectiveness of a nutrient treatment on the extent of biotransformation by up to 25% and 20% for the aliphatic and aromatic hydrocarbon fractions, respectively. This is likely due to the disruption to the indigenous microbial community in the soil caused by grinding. Further, ecotoxicological responses (mustard seed germination and Microtox assays) showed that a reduction of total petroleum hydrocarbon (TPH) concentration in soil was not directly correlable to reduction in toxicity; thus monitoring TPH alone is not sufficient for assessing the environmental risk of a contaminated site after remediation.

Polyphenolic extracts of cherry (Prunus cerasus L.) and blackcurrant (Ribes nigrum L.) leaves as natural preservatives in meat products.

The objective of this study was to evaluate the possibility of using polyphenolic extracts from cherry and blackcurrant leaves as natural antimicrobial agents in meat products. The polyphenolic composition of the extracts was analyzed and their impact on the microbial quality, lipid oxidation, color, and sensory evaluation of pork sausages was studied. Polyphenolic extracts were obtained from leaves collected in September. The total polyphenolic content in sour cherry leaf extract was 1.5 times higher than that found in blackcurrant leaf extract. Analysis of the polyphenol profile of each extract revealed two major groups: phenolic acids and flavonoids, including epigallocatechin and glycosides of quercetin and kaempferol. After chilling the sausages for 14 and 28 days, the extracts caused significantly lower MDA generation, indicating an antioxidant effect. Color changes after 28 days of storage were perceptible in the case of all treatments, with and without polyphenols. The application of sour cherry and black currant leaf extracts increased the shelf life of vacuum-packed sausages. Both extracts enhanced the microbial quality of the pork sausages over 14 days of refrigerated storage. Sour cherry leaf polyphenols were more effective against almost all studied groups of microorganisms.