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Zhayu is a type of traditional fermented fish product in China that is made through the fermentation of salted fish with a mixture of cereals and spices. Inoculation fermentation was performed using Pediococcus pentosaceus P1, Lactiplantibacillus plantarum L1, and a mixture of two strains, which were isolated from cured fish in Hunan Province. Compared with the natural fermentation, inoculation with lactic acid bacteria (LAB) accelerated the degradation of myosin and actin in Zhayu, increased the trichloroacetic acid (TCA)-soluble peptide content by about 1.3-fold, reduced the colony counts of Enterobacteriaceae and Staphylococcus aureus by about 40%, and inhibited their lipid oxidation. In the texture profile analysis performed, higher levels of hardness and chewiness were observed in the inoculation groups. In this study, the bacterial community and volatile flavor compounds were detected through 16S high-throughput sequencing and headspace solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME-GC-MS). Inoculation with L. plantarum L1 reduced around 75% abundance of Klebsiella compared with the natural fermentation group, which was positively correlated with 2,3-Butanediol, resulting in a less pungent alcohol odor in Zhayu products. The abundances of 2-pentylfuran and 2-butyl-3-methylpyrazine were increased over threefold in the L1 group, which may give Zhayu its unique flavor and aroma. [ABSTRACT FROM AUTHOR]

High-throughput sequencing was used to elucidate the microbial community of strong-flavor Daqu (SFD) (surface and central parts) produced in different Chinese regions, moisture and other six kinds of quality indicators of SFD were detected. In addition, Spearman correlation coefficient was used to identify the relationships between microbial community and quality indicators. In different sample groups of surface and central parts, the differential fungal genus was Alternaria, whereas differential bacteria genera were Weissella, Pediococcus and Leuconostoc. Spearman analysis showed that fungal genera Rhizopus, Stemphylium, and Alternaria were significantly positively correlated with saccharifying ability (p <.01), whereas Rasamsonia was significantly positively correlated with esterification ability (p <.01). Weissella, Pediococcus and Burkholderia were the bacterial genera significantly positively correlated with saccharification ability of SFD samples (p <.01). This study provides a reference for investigating the relationship between microbial community and quality indicators of SFD. [ABSTRACT FROM AUTHOR]

Background: Dandruff is a chronic, recurring, and common scalp problem that is caused by several etiopathogeneses with complex mechanisms. Management of this condition is typically achieved via antifungal therapies. However, the precise roles played by microbiota in the development of the condition have not been elucidated. Despite their omnipresence on human scalp little is known about the co-occurrence/co-exclusion network of cutaneous microbiota. Results: We characterized the scalp and hair surface bacterial and fungal communities of 95 dandruff-afflicted and healthy individuals residing in China. The degree distributions of co-occurrence/co-exclusion network in fungi-bacteria and bacteria-bacteria were higher in the healthy group (P < 0.0001), whereas the betweenness values are higher in the dandruff group (P < 0.01). Meanwhile, the co-occurrence/co-exclusion network among fungi-fungi and fungi-bacteria showed that compared to the healthy group, the dandruff group had more positive links (P < 0.0001). In addition, we observed that Malassezia slooffiae, Malassezia japonica and Malassezia furfur, were more abundant in the dandruff group than in the healthy group. These microbiota were co-exclusion by either multiple bacterial genera or Malassezia sp. in healthy group. The lactic acid bacteria on the scalp and hair surface, especially the genera Lactobacillus and Lactococcus, exhibit a negative correlation with multiple bacterial genera on the scalp and hair surface. Lactobacillus plantarum and Pediococcus lactis isolated on the healthy human scalp can inhibit the growth of Staphylococcus epidermidis in vitro. Conclusions: We showed that microbial networks on scalp and hair surface with dandruff were less integrated than their healthy counterparts, with lower node degree and more positive and stronger links which were deemed to be unstable and may be more susceptible to environmental fluctuations. Lactobacillus bacteria have extensive interactions with other bacteria or fungi in the scalp and hair surface micro-ecological network and can be used as targets for improving scalp health. [ABSTRACT FROM AUTHOR]

Pickled cowpea (Vigna unguiculata [Linn.] Walp) is a popular fermented vegetable in China that is made by spontaneous fermentation. Prior to this study, little was known about its microbial community. Eighteen pickled cowpea samples were collected in Enshi City, China, in 2018. The bacterial diversity within these samples was evaluated using a combination of high-throughput sequencing (Illumina MiSeq platform) targeting the V3–V4 region of the 16S rRNA gene sequence and culture-dependent methods. A total of 456,318 high-quality 16S rRNA gene sequence reads were obtained, and these reads were clustered into 19,712 OTUs with 97.0% similarity. The core bacterial phyla were Actinobacteria, Bacteroidetes, Proteobacteria, and Firmicutes; the core bacterial genera were Levilactobacillus, Lactiplantibacillus, Companilactobacillus, Pediococcus, Lactobacillus, Weissella, and Pseudomonas. Using the spread-plating method, 39 lactic acid bacteria (LAB) strains were isolated and identified based on the nearly complete 16S rRNA gene sequence. Of these, 37 were identified as Lactiplantibacillus plantarum group, while the other two were classified as Limosilactobacillus fermentum and Lacticaseibacillus rhamnosus. These results indicate a high relative abundance of LAB in traditional pickled cowpea, especially Lactobacillaceae species, which likely contribute to fermentation. This study would provide information on the LAB population of Pickled cowpea and indicated that the Pickled cowpea could be a good source for isolation of lactic acid bacteria. [ABSTRACT FROM AUTHOR]

Mud crabs (Scylla paramamosain), a commercially important cultured species in the southeastern region of China, is usually infected by Vibriosis or parasites, causing great economic losses in cultured farms. Previous studies have demonstrated that probiotics benefited in enhancing the immune response against invading pathogens in aquatic animals. In this study, the effects of dietary administration of lactic acid bacteria (LAB) (Enterococcus faecalis Y17 and Pediococcus pentosaceus G11) on growth performance and immune responses of mud crab were assessed. Both strains (Y17 and G11) showed an inhibitory activity against bacterial pathogens (Aeromonas hydrophila , Vibrio parahaemolyticus , Vibrio alginolyticus , Staphylococcus aureus , and β Streptococcus), and a wide pH tolerance range of 2–10. In vivo , mud crabs were fed a control diet and experimental diets supplemented with 109 cfu g−1 diet either Y17 or G11 for 6 weeks before subjecting to a challenge test with V. parahaemolyticus for 12 h. The probiotic-supplemented diets had significant effects on weight gain and specific growth rate during the feeding trial. Increased serum enzyme activities of phenoloxidase, lysozyme, and SOD were observed in the hemolymph of mud crab in Y17 and G11-supplemented groups compared to that in the controls (P < 0.01). The significantly up-regulated expression of gene CAT, LYS, proPO, and SOD could be seen in hepatopancreas in G11-supplemented groups. After the pathogenicity test, the survival rate of Y17 + and G11 + V. parahaemolyticus groups was 66.67% and 80.00%, respectively, compared with 53.33% for the control groups. Taken together, dietary supplementation of Y17 and G11 strains were beneficial in mud crab, which could increase growth performance, modulate immune system and protect the host against V. parahaemolyticus infection. • Two lactic acid bacteria (Y17 and G11) showed inhibitory activities against bacterial pathogens. • The Y17/G11-supplemented diets had significant effect on weight gain and specific growth rate. • Improved immune protection of Y17/G11-supplemented diets against the pathogen challenges. • The survival rate of the treatment groups increased compared with that of the controls. [ABSTRACT FROM AUTHOR]

Koji is used as a fermentation starter in Choujiu manufacture in northwestern China. Traditional natural Koji (NK) cultivates in open environments, which probably leads to diverse microflora, causes inconsistent quantities in Koji, then results in instable qualities of Choujiu. A native Choujiu producer has been purchasing NK from local workshop, while their Choujiu qualities fluctuate by the stability of NK. As a request from the producer, this study aimed for stable Koji and inheriting sensory traits of current products. Strains of mold, yeast, and LAB, separated from NK, were selected for Restored Koji (RK) making. Brewing performance of RK and NK were compared by analysis of the physicochemical properties and volatile flavor compounds (VFCs) in fermented mash, combined with sensory evaluation in corresponding Choujiu. Pure Koji from individual strains was separately cultured at 28 °C for 48 h, and then reconstituted for RK II at the proportion of mold Koji (M7 Koji): yeast Koji (Y3 Koji: Y4 Koji = 1:1): LAB Koji (L1 Koji) = 1:1:1, where M7 was Rhizopus oryzae , Y3 was Saccharomyces cerevisiae , Y4 was Saccharomycopsis fibuligera , and L1 was Pediococcus pentosaceus. Results showed RK II could meet the desired purpose of this study. • A new restored Koji (RK) was developed with four strains separated from natural Koji. • RK performs better fermentation ability, remains original sensory traits of Choujiu. • RK can replace natural Koji for industrial application. [ABSTRACT FROM AUTHOR]

• Co-inoculation of Z. rouxii and T. candida could inhibit BAs formation. • Inoculation of S. piscifermentans could further reduce BAs production. • Volatile compounds were enhanced after inoculation of S. piscifermentans. • Inoculation of S. piscifermentans altered the microflora in the soy sauce mash. With the increasing popularity of soy sauce containing high amounts of amino acid nitrogen (AAN) in China and the positive correlation of biogenic amines (BAs) with AAN, reducing BAs formation during soy sauce fermentation has become an urgent task. In this work, the effect of salt-tolerant yeasts and Staphylococcus piscifermentans on BAs formation was extensively studied. Combined inoculation for different osmotolerant yeast strains indicated that Z. rouxii CICC 1417 and T. candida CICC 1019 co-inoculation produced the lowest amount of BAs (89.43 mg/L). Furthermore, co-inoculation of soy sauce mash with S. piscifermentans and salt-tolerant yeasts reduced the BAs production by 31.51% under laboratory-scale experiments. Only 133.40 g/L BAs were produced after S. piscifermentans inoculation in 50-T fermentator, and this value was 63.25% lower than that of the control. Most of the alcohols, aldehydes, phenols, and esters were increased, whereas bacteria, such as Pediococcus , Weissella , and Streptococcus , were inhibited and thus reduced BAs formation. The increased abundance in Zygosaccharomyces and Pichia may contribute to the improvement in volatile compound production. These findings reveal the high potential of the co-inoculation of S. piscifermentans and salt-tolerant yeasts for soy sauce production with limited BAs formation. [ABSTRACT FROM AUTHOR]

• Firmicutes and Cyanobacteria were major phylum in Suancai. • Lactobacillus and Pediococcus were the biomarker of LS and HS, respectively. • Lactobacillus and Pediococcus were correlated with flavors in Suancai. • The inoculated of P. pentosaceus improve the alcohols and nitriles in Suancai. • The co-inoculated of L. plantarum and P. pentosaceus improve the flavors in Suancai. Suancai, a popular traditional fermented cabbage in northeast China, is commonly prepared by the spontaneous fermentation process at a certain salt concentration. The salt can affect the metabolites by affecting the microorganisms during Suancai fermentation. The bacterial community and volatile flavor compounds in commercial Suancai from different regions of Northeastern China at different salt concentrations were investigated using next-generation sequencing and GC–MS. Firmicutes and Cyanobacteria were the dominant phyla in the commercial Suancai, and Lactobacillus , Pediococcus , and Leuconostoc were the dominant genera. Among them, Lactobacillus and Pediococcus were considered as the biomarkers of the low and high salt Suncai, respectively. Eighty-five volatile flavor compounds were detected, and HS exhibited higher contents of volatile flavor compounds than LS. Based on the results of correlation analysis, Pediococcus were highly correlated with the alcohols and nitriles in Suancai. The contents of alcohols and nitriles significantly increased in the Suancai, fermented by Pediococcus pentosaceus. The co-inoculated fermentation of Lactobacillus plantarum and P. pentosaceus could increase the concentrations of alcohols, esters, aldehydes, hydrocarbons, and nitriles in Suancai. This study provides a perspective for understanding the ecology of Suancai fermentation and facilitating the fermentation with multispecies inoculation fermentation at an appropriate salt concentration. [ABSTRACT FROM AUTHOR]