Maize is one the most important staple foods in the world. However, numerous pests, such as fungal pathogens, e.g., Fusarium verticillioides, and insects, such as Sitophlilus zeamais, attack maize grains during storage. Many F. verticillioides strains produce fumonisins, one of the most important mycotoxin that causes toxic effects on human and animal health. This situation is aggravated by the insect fungal vector, Sitophlilus zeamais, which contributes to the dispersal of fungal spores, and through feeding damage, provide entry points for fungal infections. The aim of this study was to evaluate in vitro bioassays, the antifungal activity on F. verticillioides M3125 and repellent effects against S. zeamais of ketone terpenes. In addition, we performed Quantitative structure-activity relationship (Q-SAR) studies between physico-chemical properties of ketone terpenes and the antifungal effect. Thymoquinone was the most active compound against F. verticillioides (Minimum Inhibitory Concentration, MIC: 0.87) affecting the lag phase and the growth rate showing a total inhibition of growth at concentration higher than 2 mM (p < 0.05). The Q-SAR model revealed that the antifungal activity of ketone compounds is related to the electronic descriptor, Pi energy. Thymoquinone showed a strong repellent effect (-77.8 ± 8.5, p < 0.001) against S. zeamais. These findings make an important contribution to the search for new compounds to control two stored pests of maize.

Bacteria and fungi emit a huge variety of volatile organic compounds (VOCs) that can provide a valuable arsenal for practical use. However, the biological activities and functions of the VOCs are poorly understood. This work aimed to study the action of individual VOCs on the bacteria Agrobacterium tumefaciens, Arabidopsis thaliana plants, and fruit flies Drosophila melanogaster. VOCs used in the work included ketones, alcohols, and terpenes. The potent inhibitory effect on the growth of A. tumefaciens was shown for 2-octanone and isoamyl alcohol. Terpenes (-)-limonene and (+)-α-pinene practically did not act on bacteria, even at high doses (up to 400 µmol). 2-Butanone and 2-pentanone increased the biomass of A. thaliana at doses of 200-400 μmol by 1.5-2 times; 2-octanone had the same effect at 10 μmol and decreased plant biomass at higher doses. Isoamyl alcohol and 2-phenylethanol suppressed plant biomass several times at doses of 50-100 μmol. Plant seed germination was most strongly suppressed by isoamyl alcohol and 2-phenylethanol. The substantial killing effect (at low doses) on D. melanogaster was exerted by the terpenes and the ketones 2-octanone and 2-pentanone. The obtained data showed new information about the biological activities of VOCs in relation to organisms belonging to different kingdoms.

Volatile organic compounds (VOCs) emitted by bacteria play an important role in the interaction between microorganisms and other organisms. They can inhibit the growth of phytopathogenic microorganisms, modulate plant growth, and serve as infochemicals. Here, we investigated the effects of ketones, alcohols, and terpenes on the colony biofilms of plant pathogenic Agrobacterium tumefaciens strains and swimming motility, which can play an important role in the formation of biofilms. It was shown that 2-octanone had the greatest inhibitory effect on biofilm formation, acting in a small amount (38.7 g/m3). Ketone 2-butanone and unsaturated ketone β-ionone reduced the formation of biofilms at higher doses (145.2-580.6 and 387.1-1548.3 g/m3, respectively, up to 2.5-5 times). Isoamyl alcohol and 2-phenylethanol decreased the formation of biofilms at doses of 88.7 and 122.9 g/m3 by 1.7 and 5 times, respectively, with an increased effect at 177.4 and 245.9 g/m3, respectively. The agrobacteria cells in mature biofilms were more resistant to the action of ketones and alcohols. These VOCs also suppressed the swimming motility of agrobacteria; the radius of swimming zones decreased ~from 2 to 5 times. Terpenes (-)-limonene and (+)-α-pinene had no significant influence on the colony biofilms and swimming motility at the doses used. The results obtained represent new information about the effect of VOCs on biofilms and the motility of bacteria.

The Streptomyces produce a great diversity of specialized metabolites, including highly volatile compounds with potential biological activities. Volatile organic compounds (VOCs) produced by nine Streptomyces spp., some of which are of industrial importance, were collected and identified using gas chromatography-mass spectrometry (GC-MS). Biosynthetic gene clusters (BGCs) present in the genomes of the respective Streptomyces spp. were also predicted to match them with the VOCs detected. Overall, 33 specific VOCs were identified, of which the production of 16 has not been previously reported in the Streptomyces. Among chemical classes, the most abundant VOCs were terpenes, which is consistent with predicted biosynthetic capabilities. In addition, 27 of the identified VOCs were plant-associated, demonstrating that some Streptomyces spp. can also produce such molecules. It is possible that some of the VOCs detected in the current study have roles in the interaction of Streptomyces with plants and other higher organisms, which might provide opportunities for their application in agriculture or industry.

A new type of fruit wine made from red dragon fruit juice was produced through alcoholic fermentation (AF) with different yeasts: Saccharomyces cerevisiae EC-1118, Torulaspora delbrueckii Biodiva and Lachancea thermotolerans Concerto. Complete AF with similar fermentation rates in terms of sugar utilisation and ethanol production (8-9%, v/v) was achieved by three yeast strains. T. delbrueckii produced a significantly lower amount of glycerol and acetic acid, while L. thermotolerans produced more lactic and succinic acids. In addition, the two non-Saccharomyces strains were more efficient in proline utilisation. For volatile compounds, S. cerevisiae produced the highest amounts of esters, while T. delbrueckii produced more higher alcohols, isoamyl acetate and terpenes. On the other hand, AF caused significant degradation of betacyanin pigments and total phenolic compounds. Nevertheless, better retention of antioxidant activity and colour stability was found in L. thermotolerans and T. delbrueckii fermented wines than that of S. cerevisiae. This study suggested that it is feasible to use pure non-Saccharomyces yeast to produce red dragon fruit wine for commercialization.

Marine bacteria are a significant source of bioactive compounds for various biotechnological applications. Among these, actinomycetes have been found to produce a wide range of secondary metabolites of interest. Saccharopolyspora is one of the genera of actinomycetes that has been recognized as a potential source of these compounds. This study reports the characterization and genomic analysis of Saccharopolyspora sp. NFXS83, a marine bacterium isolated from seawater from the Sado estuary in Portugal. The NFXS83 strain produced multiple functional and stable extracellular enzymes under high-salt conditions, showed the ability to synthesize auxins such as indole-3-acetic acid, and produced diffusible secondary metabolites capable of inhibiting the growth of Staphylococcus aureus. Furthermore, when Phaeodactylum tricornutum was co-cultivated with strain NFXS83 a significant increase in microalgae cell count, cell size, auto-fluorescence, and fucoxanthin content was observed. Detailed analysis revealed the presence of clusters involved in the production of various secondary metabolites, including extracellular enzymes, antimicrobial compounds, terpenes, and carotenoids in the genome of strain NFXS83. Ultimately, these findings indicate that Saccharopolyspora sp. NFXS83 has a significant potential for a wide range of marine biotechnological applications.

The spontaneous fermentation of alcoholic beverage is a bioprocess donated by microbiota with complex stress environments. Among various microbes, non-Saccharomyces yeasts have high stress tolerance and significantly affect the taste and quality of products in process. Although many researchers have focused on the influence of acid stress, the mechanism of non-Saccharomyces yeasts to tolerant stress remains unclear in microbiota. To bridge the gap, we constructed in situ and in vitro studies to explore the reduction pathway of acetic acid in non-Saccharomyces yeasts. In this study, we found Schizosaccharomyces pombe has special capacities to resist 10 g/L acetic acid in laboratory cultures and decrease the average concentration of acetic acid from 9.62 to 6.55 g/kg fermented grains in Chinese Maotai-flavor liquor (Baijiu) production. Moreover, Schi. pombe promoted metabolic level of mevalonate pathway (high expressions of gene ACCAT1, HMGCS1, and HMGCR1) to degrade a high concentration of acetic acid. Meanwhile, Schi. pombe also improved the concentration of mevalonic acid that is the precursor of terpenes to enhance the taste and quality of Baijiu. Overall, the synchronicity of reduction and generation in Schi. pombe advances the current knowledge to guide more suitable strategies for mechanism studies of non-Saccharomyces yeasts in fermented industries of alcoholic beverages.

This study aimed to determine the probiotic potential of Pediococcus acidilactici M76 (PA-M76) for lactic acid fermentation of black raspberry extract (BRE). PA-M76 showed outstanding probiotic properties with high tolerance in acidic GIT environments, broad antimicrobial activity, and high adhesion capability in the intestinal tract of Caenorhabditis elegans. PA-M76 treatment resulted in significant increases of pro-inflammatory cytokine mRNA expression in macrophages, indicating that PA-M76 elicits an effective immune response. When PA-M76 was used for lactic acid fermentation of BRE, an EPS yield of 1.62 g/L was obtained under optimal conditions. Lactic acid fermentation of BRE by PA-M76 did not significantly affect the total anthocyanin and flavonoid content, except for a significant increase in total polyphenol content compared to non-fermented BRE (NfBRE). However, fBRE exhibited increased DPPH radical scavenging activity, linoleic acid peroxidation inhibition rate, and ABTS scavenging activity of fBRE compared to NfBRE. Among the 28 compounds identified in the GC-MS analysis, esters were present as the major groups. The total concentration of volatile compounds was higher in fBRE than that in NfBRE. However, the undesirable flavor of terpenes decreased. PA-M76 might be useful for preparing functionally enhanced fermented beverages with a higher antioxidant activity of EPS and enhanced flavors.

Alcoholic fermentation is known to be a key stage in the winemaking process that directly impacts the composition and quality of the final product. Twelve wines were obtained from fermentations of Chardonnay must made with twelve different commercial wine yeast strains of Saccharomyces cerevisiae. In our study, FT-ICR-MS, GC-MS, and sensory analysis were combined with multivariate analysis. Ultra-high-resolution mass spectrometry (uHRMS) was able to highlight hundreds of metabolites specific to each strain from the same species, although they are characterized by the same technological performances. Furthermore, the significant involvement of nitrogen metabolism in this differentiation was considered. The modulation of primary metabolism was also noted at the volatilome and sensory levels. Sensory analysis allowed us to classify wines into three groups based on descriptors associated with white wine. Thirty-five of the volatile compounds analyzed, including esters, medium-chain fatty acids, superior alcohols, and terpenes discriminate and give details about differences between wines. Therefore, phenotypic differences within the same species revealed metabolic differences that resulted in the diversity of the volatile fraction that participates in the palette of the sensory pattern. This original combination of metabolomics with the volatilome and sensory approaches provides an integrative vision of the characteristics of a given strain. Metabolomics shine the new light on intraspecific discrimination in the Saccharomyces cerevisiae species.

In view of the fast depleting armamentarium of drugs against significant pathogens, like methicillin-resistant Staphylococcus aureus (MRSA) and others due to rapidly emerging drug-resistance, the discovery and development of new drugs need urgent action. In this endeavor, a new strain of endophytic actinobacterium was isolated from the plant Datura metesl, which produced secondary metabolites with potent anti-infective activities. The isolate was identified as Streptomyces californicus strain ADR1 based on 16S rRNA gene sequence analysis. Metabolites produced by the isolate had been investigated for their antibacterial attributes against important pathogens: S. aureus, MRSA, S. epidermis, Enterococcus faecium and E. faecalis. Minimum inhibitory concentration (MIC90) values against these pathogens varied from 0.23 ± 0.01 to 5.68 ± 0.20 μg/mL. The metabolites inhibited biofilm formation by the strains of S. aureus and MRSA (Biofilm inhibitory concentration [BIC90] values: 0.74 ± 0.08-4.92 ± 0.49 μg/mL). The BIC90 values increased in the case of pre-formed biofilms. Additionally, the metabolites possessed good antioxidant properties, with an inhibitory concentration (IC90) value of 217.24 ± 6.77 µg/mL for 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging. An insight into different classes of compounds produced by the strain ADR1 was obtained by chemical profiling and GC-MS analysis, wherein several therapeutic classes, for example, alkaloids, phenolics, terpenes, terpenoids and glycosides, were discovered.

In the present study, three commercial yeasts (for wine, beer, and cider) were evaluated for the production of pomegranate alcoholic beverage (PAB) from a juice of Wonderful variety. The physicochemical characteristics, antioxidant activity, and aromatic profiles of PABs were investigated before and after fermentation, while the effect of yeast strain and fermentation temperature (15 and 25 °C) was also evaluated. The PABs contained ethanol in the ranges of 5.6-7.0% v/v, in combination with glycerol (2.65-6.05 g L-1), and low volatile acidity. Total flavonoid content, total phenolic content, free radical-scavenging activity, and total monomeric anthocyanin content appeared to decrease after fermentation, possibly due to hydrolysis, oxidation, and other reactions. In general, PABs retained 81-91% of free radical-scavenging activity, 29-41% of phenolics, 24-55% of flavonoids, and 66-75% of anthocyanins. The use of different yeast affected mainly flavonoids and anthocyanins, and yeast strain M02 resulted in the highest values after fermentation. In PABs, 30 different volatile compounds were identified, specifically 15 esters, 4 organic acids, 8 alcohols, and 3 terpenes. The principal component analysis showed that the fermentation temperature affected significantly volatile composition, whereas, among the yeasts, WB06 is the one that seems to differentiate. The findings of this study show that the selection of the appropriate yeast and fermentation temperature is very crucial and affects the characteristics of the final product.

Antarctic krill (Euphausia superba) is a key species of the Antarctic ecosystem whose unique ecological status and great development potential have attracted extensive attention. However, the genomic characteristics and potential biological functions of the symbiotic microorganisms of Antarctic krill remain unknown. In this study, we cultured and identified a strain of Brucella sp. WY7 from Antarctic krill using whole-genome sequencing and assembly, functional annotation, and comparative genomics analysis. First, based on 16S rDNA sequence alignment and phylogenetic tree analysis, we identified strain WY7 as Brucella. The assembled genome of strain WY7 revealed that it has two chromosomes and a plasmid, with a total genome length of 4,698,850 bp and an average G + C content of 57.18%. The DNA-DNA hybridization value and average nucleotide identity value of strain WY7 and Brucella anthropi ATCC® 49188TM, a type strain isolated from human clinical specimens, were 94.8% and 99.07%, respectively, indicating that strain WY7 is closely related to Brucella anthropi. Genomic island prediction showed that the strain has 60 genomic islands, which may produce HigB and VapC toxins. AntiSMASH analysis results showed that strain WY7 might produce many secondary metabolites, such as terpenes, siderophores and ectoine. Moreover, the genome contains genes involved in the degradation of aromatic compounds, suggesting that strain WY7 can use aromatic compounds in its metabolism. Our work will help to understand the genomic characteristics and metabolic potential of bacterial strains isolated from Antarctic krill, thereby revealing their roles in Antarctic krill and marine ecosystems.

In this paper, the volatile flavour constituents and the bacterial diversity in characteristic Chinese fermented sour soup were analysed, and the dynamics of bacteria associated with the odour were characterized. The bacterial diversity of sour soup was studied by high-throughput sequencing. A total of 10 phyla and 89 genera were detected. Firmicutes was the dominant phylum of sour soup, accounting for 87.14-98.57%. The genus structure of normal sour soup was relatively simple, and Lactobacillus (78.05-90.26%) was the dominant genus. In addition to Lactobacillus, the foul-smelling sour soup contained more Pediococcus spp., Caproiciproducens spp., and Clostridium-sensu-stricto12 spp. (relative abundance >1%) than the normal sour soup. A total of 51 aroma compounds were detected by gas chromatography-mass spectrometry(GC-IMS), including 25 esters, 8 terpenes, 8 alcohols, 3 sulfur compounds, 2 acids, 2 ketones, 1 pyrazine, 1 monoterpene and 1 aldehyde. According to the relative odour active value (ROAV) calculation, 51 important flavour-contributing substances and 7 flavour-coordinating substances were determined. The esters with the highest relative percentages and ROAV values provided the pleasant flavour of the sour soup. In the foul-smelling sour soup, the ROAV values of 1,8-cineole, isobutyl acetate, ethyl butanoate, ethyl octanoate-M, and ethyl hexanoate-M decreased, while those of diallyl disulfide-M and diallyl disulfide-D, which were probably responsible for the foul flavour, increased. Through Pearson correlation analysis, the odour production of the foul-smelling soup was determined to be related to Pediococcus spp., Caproiciproducens spp., Clostridiumsensu_stricto_12 spp., Oscillibacter spp., Bacteroides spp., Fibaculaceae_unclassified spp., Acinetobacter spp. and Halomonas spp.

Aniseeds (Pimpinella anisum) have gained increasing attention for their nutritional and health benefits. Aniseed extracts are known to contain a range of compounds, including flavonoids, terpenes, and essential oils. These compounds have antimicrobial properties, meaning they can help inhibit the growth of nasty bacteria and other microbes. The purpose of this study was to determine if aniseed extracts have potential antioxidant, phytochemical, and antimicrobial properties against multidrug-resistant (MDR) bacteria. A disc diffusion test was conducted in vitro to test the aniseed methanolic extract's antibacterial activity. The MIC, MBC, and inhibition zone diameters measure the minimum inhibitory concentration, minimum bactericidal concentration, and size of the zone developed when the extract is placed on a bacterial culture, respectively. HPLC and GC/MS are analytical techniques used for identifying the phenolics and chemical constituents in the extract. DPPH, ABTS, and iron-reducing power assays were performed to evaluate the total antioxidant capacity of the extract. Using HPLC, oxygenated monoterpenes represented the majority of the aniseed content, mainly estragole, cis-anethole, and trans-anethole at 4422.39, 3150.11, and 2312.11 (g/g), respectively. All of the examined bacteria are very sensitive to aniseed's antibacterial effects. It is thought that aniseed's antibacterial activity could be attributed to the presence of phenolic compounds which include catechins, methyl gallates, caffeic acid, and syringic acids. According to the GC analysis, several flavonoids were detected, including catechin, isochiapin, and trans-ferulic acid, as well as quercitin rhamnose, kaempferol-O-rutinoside, gibberellic acid, and hexadecadienoic acid. Upon quantification of the most abundant estragole, we found that estragole recovery was sufficient for proving its antimicrobial activity against MDR bacteria. Utilizing three methods, the extract demonstrated strong antioxidant activity. Aniseed extract clearly inhibited MDR bacterial isolates, indicating its potential use as an anti-virulence strategy. It is assumed that polyphenolic acids and flavonoids are responsible for this activity. Trans-anethole and estragole were aniseed chemotypes. Aniseed extracts showed higher antioxidant activity than vitamin C. Future investigations into the compatibility and synergism of aniseed phenolic compounds with commercial antibacterial treatments may also show them to be promising options.

Fermented milk products (FMPs) contain probiotics that are live bacteria considered to be beneficial to human health due to the production of various bioactive molecules. In this study, nine artisanal FMPs (kefir, ayran, khurunga, shubat, two cottage cheeses, bryndza, khuruud and suluguni-like cheese) from different regions of Russia were characterized using metagenomics. A metagenomic sequencing of ayran, khurunga, shubat, khuruud and suluguni-like cheese was performed for the first time. The taxonomic profiling of metagenomic reads revealed that Lactococcus species, such as Lc. lactis and Lc. cremoris prevailed in khuruud, bryndza, one sample of cottage cheese and khurunga. The latter one together with suluguni-like cheese microbiome was dominated by bacteria, affiliated to Lactobacillus helveticus (32-35%). In addition, a high proportion of sequences belonging to the genera Lactobacillus, Lactococcus and Streptococcus but not classified at the species level were found in the suluguni-like cheese. Lactobacillus delbrueckii, as well as Streptococcus thermophilus constituted the majority in another cottage cheese, kefir and ayran metagenomes. The microbiome of shubat, produced from camel's milk, was significantly distinctive, and Lentilactobacillus kefiri, Lactobacillus kefiranofaciens and Bifidobacterium mongoliense represented the dominant components (42, 7.4 and 5.6%, respectively). In total, 78 metagenome-assembled genomes with a completeness ≥ 50.2% and a contamination ≤ 8.5% were recovered: 61 genomes were assigned to the Enterococcaceae, Lactobacillaceae and Streptococcaceae families (the Lactobacillales order within Firmicutes), 4 to Bifidobacteriaceae (the Actinobacteriota phylum) and 2 to Acetobacteraceae (the Proteobacteria phylum). A metagenomic analysis revealed numerous genes, from 161 to 1301 in different products, encoding glycoside hydrolases and glycosyltransferases predicted to participate in lactose, alpha-glucans and peptidoglycan hydrolysis as well as exopolysaccharides synthesis. A large number of secondary metabolite biosynthetic gene clusters, such as lanthipeptides, unclassified bacteriocins, nonribosomal peptides and polyketide synthases were also detected. Finally, the genes involved in the synthesis of bioactive compounds like β-lactones, terpenes and furans, nontypical for fermented milk products, were also found. The metagenomes of kefir, ayran and shubat was shown to contain either no or a very low count of antibiotic resistance genes. Altogether, our results show that traditional indigenous fermented products are a promising source of novel probiotic bacteria with beneficial properties for medical and food industries.