scholarly journals Characterization and Biological Activity of a Novel Exopolysaccharide Produced by Pediococcus pentosaceus SSC–12 from Silage

2021 ◽  
Vol 10 (1) ◽  
pp. 18
Author(s):  
Yang Fan ◽  
Xinqin Li ◽  
Rong Tian ◽  
Ruxue Tang ◽  
Jianguo Zhang

In this study, 22 strains of exopolysaccharides-producing lactic acid bacteria were isolated from silage, and the strain SSC–12 with the highest exopolysaccharide (EPS) production was used as the test strain. The SSC–12 was identified as Pediococcus pentosaceus, based upon 16S rDNA gene sequencing and Neighbor Joining (NJ) phylogenetic analysis. The analysis of the kinetic results of EPS generation of SSC–12 showed that the EPS generation reached the maximum value at 20 h of culture. The characterization study showed the EPS produced by SSC–12 was a homogeneous heteropolysaccharide comprising glucose (42.6%), mannose (28.9%), galactose (16.2%), arabinose (9.4%), and rhamnose (2.9%). The EPS had good antioxidant activity, especially the activity of scavenging hydroxyl free radicals. At the same time, the EPS also had strong antibacterial ability and could completely inhibit the growth of Staphylococcus aureus. The EPS produced by the Pediococcus pentosaceus SSC–12 can be used as a biologically active product with potential application prospects in the feed, food, and pharmaceutical industries.

2018 ◽  
Vol 3 (1) ◽  
pp. 18-24
Author(s):  
Laya Tabrizi Rayeni ◽  
Shahla Soltani Nezhad

Background: Breast milk is an important nutrient source for rapidly growing neonates since breastfeeding protects the newborn against some disease. This effect may be due to the useful and natural microflora of breast milk. Biosurfactants are unique amphipathic compounds produced by some microorganisms. The present study demonstrates the isolation and characterization of biosurfactant producing bacteria from human breast milk samples. Methods: The human breast milk samples were collected aseptically and then cultured in MRS agar media. The biosurfactant producing ability of the isolated strains was investigated by hemolytic assay, oil spreading method, drop collapse test and emulsification index assay. The screened isolates were identified by 16S rDNA gene sequencing analysis. In vitro antibacterial activities of biosurfactants against some Gram-positive and Gram negative bacteria were investigated by the agar disc diffusion method. This biosurfactant was characterized with Fourier transform infrared spectroscopy (FTIR). Results: In this study, 337 different colonies were isolated from 42 breast milk samples. The best isolates were identified as Pediococcus pentosaceus HM-1, Pediococcus pentosaceus HM-2 and Pediococcus pentosaceus HM-3 based on microscopic and 16S rDNA gene sequencing analysis. The biosurfactant extracted from screened strains exhibited a broad spectrum of antagonistic activity against some pathogenic bacteria. The results showed similarity to lipopeptide biosurfactants like surfactin. Conclusion: Bacterial strains isolated in this study could be valuable sources for novel biosurfactants. The Human breast milk could be a safe source for isolation of biosurfactant producing probiotic bacteria and for improve intestinal microflora of infants.


Author(s):  
L.A. Maldonado ◽  
M.E. Hamid ◽  
O.A. Gamal El Din ◽  
M. Goodfellow

Fifteen of 100 mastitic milk samples from goats suffering from mastitis were tentatively identified as members of the genus Nocardia on the basis of selected phenotypic and chemotaxonomic characteristics. Six of the 15 strains were confirmed as Nocardia farcinica by 16S rDNA gene sequencing and subsequent aligning with relevant actinomycetes found in electronic databases and 2 by other identification criteria. N. farcinica is a serious cause of mastitis with a significant prevalence (15%) among the examined goats. Efforts are needed to optimise and simplify isolation and identification methods.


2019 ◽  
Vol 6 (11) ◽  
pp. 190562 ◽  
Author(s):  
Qingming Zhang ◽  
Hongyu Liu ◽  
Muhammad Saleem ◽  
Caixia Wang

Chlorothalonil is a widely used fungicide, but the contamination of soil and water environments by this chemical causes potential threats to biodiversity. Given the metabolic potential of soil microorganisms, there is a need for developing microbiological approaches to degrade persistent compounds, such as chlorothalonil, in contaminated sites. Here in this study, we isolated a bacterial strain (namely, BJ1) capable of degrading chlorothalonil from a chlorothalonil-contaminated farmland soil in the Shandong Province, China. Using 16S rDNA gene sequencing, morphological and biological characteristics, we identified the strain BJ1 as Stenotrophomonas acidaminiphila . The strain BJ1 uses chlorothalonil as a sole carbon source. At initial concentrations of 50, 100, 200 and 300 mg l −1 , it degraded 91.5%, 89.4%, 86.5% and 83.5% of chlorothalonil after 96 h of inoculation under optimum conditions (30°C and pH 7.0). Two metabolites, methyl-2,5,6-trichloro-3-cyano-4-methoxy-benzoate and methyl-3-cyano-2,4,5,6-tetrachlorobenzoate, were detected and identified based on HPLC–MS analysis, which suggests that the strain BJ1 metabolized chlorothalonil through the hydroxylation of chloro-group and hydration of cyano-group. The results of this study highlight the great potential for this bacterium to be used in chlorothalonil pollution remediation.


Foods ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2916
Author(s):  
Nelson Pereira ◽  
Carla Alegria ◽  
Cristina Aleixo ◽  
Paula Martins ◽  
Elsa M. Gonçalves ◽  
...  

Lactic fermentation of unripe green tomatoes as a tool to produce food ingredients is a viable alternative for adding value to industrial tomatoes unsuitable for processing and left in large quantities in the fields. Fermentation using starter cultures isolated from the fruit (plant-matrix adapted) can have advantages over allochthonous strains in obtaining fermented products with sensory acceptability and potentially probiotic characteristics. This paper details the characterisation of the unripe green tomato lactic microbiota to screen LAB strains for use as starter cultures in fermentation processes, along with LAB strains available from INIAV’s collection. Morphological, biochemical (API system), and genomic (16S rDNA gene sequencing) identification showed that the dominant LAB genera in unripe green tomato are Lactiplantibacillus, Leuconostoc, and Weissella. Among nine tested strains, autochthonous Lactiplantibacillus plantarum and allochthonous Weissella paramesenteroides showed tolerance to added solanine (200 ppm) and the best in vitro probiotic potential. The results indicate that the two LAB strains are promising candidates for manufacturing probiotic fermented foods from unripe green tomatoes.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Elisa Maria de Oliveira ◽  
Victor Hugo Gomes Sales ◽  
Marcelo Silva Andrade ◽  
Jerri Édson Zilli ◽  
Wardsson Lustrino Borges ◽  
...  

The objective of this research was to perform screening of biosurfactant-producing bacteria from Amapaense Amazon soils. Floodplain- and upland-forest soils of three municipalities of the Amapá state were isolated and identified. The isolates were cultured in nutrient broth with olive oil, and their extracts were evaluated according to drop collapse, oil dispersion, emulsification, and surface tension tests. From three hundred and eighteen isolates, the 43 bacteria were selected and identified by 16S rDNA gene sequencing, indicating the presence of three different genera, Serratia, Paenibacillus, and Citrobacter. The extracellular biosurfactant production pointed out the 15 most efficient bacteria that presented high emulsification capacity (E24 > 48%) and stability (less than 10% of drop after 72 h) and great potential to reduce the surface tension (varying from 49.40 to 34.50 mN·m−1). Cluster analysis classified genetically related isolates in different groups, which can be connected to differences in the amount or the sort of biosurfactants. Isolates from Serratia genus presented better emulsification capacity and produced a more significant surface tension drop, indicating a promising potential for biotechnological applications.


2019 ◽  
Vol 37 (3) ◽  
pp. 255-262
Author(s):  
Reneé Pérez-Pérez ◽  
Maxime Oudot ◽  
Lizette Serrano ◽  
Ionel Hernández ◽  
María Nápoles ◽  
...  

Rhizobia have been studied for the symbiosis that they establish with the roots of legumes. However, the colonization and promotion of growth in non-leguminous plants has also been demonstrated. The aim of this work was the biochemical and molecular identification of rhizosphere rhizobia present inthe rhizosphere of two commercial maize cultivars. Cultivableisolates were obtained in yeast-mannitol-agar (YMA) mediumfrom rhizospheric soil and the rhizoplane. The cultural (size,color, mucus, etc.), morphological, and staining (cell shape,response to staining and sporulation) characteristics weredetermined as well as isolate responses to eight biochemicaltests (acid-base production, citrate, oxidase, catalase, H2Sproduction, urease, gelatinase and the oxidative-fermentativeassay) that are valuable for rhizobia identification. The genuswas determined by 16S rDNA gene sequencing. We obtained 81total isolates of which 30.86% showed the cultural, morphological and staining characteristics expected for rhizobia and only 20% of these corresponded to the genus Rhizobium.


Agriculture ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 10 ◽  
Author(s):  
Zhe Wu ◽  
Shengyang Xu ◽  
Ying Yun ◽  
Tingting Jia ◽  
Zhu Yu

In this study, an experiment was performed to evaluate the effect of lactic acid bacteria and 3-phenyllactic acid (PLA) on the fermentation quality and chemical composition of alfalfa silage. Several PLA-tolerant strains were screened from silages and identified. The selected strains (1 × 106 colony forming units/g fresh alfalfa) and PLA (1.0, 2.0, or 3.0 g/kg) were applied to alfalfa before ensiling. After 45 days of storage, the silages were unsealed and subjected to component analysis. Biochemical methods and 16S rDNA gene sequencing were used for the identification of the two strains as Lactobacillus plantarum. The characteristics of chemical and fermentation compounds indicated that PLA and the two strains efficiently improved the quality of the alfalfa silage. It can be concluded that the use of the strains and PLA can significantly improve the quality of silage.


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