Identification of slightly halophilic bacteria from salted sheepskin samples and investigation of their biotechnological importance / Dilek Yalcin in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 108, N° 1 (01-02/2024)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 108, N° 1 (01-02/2024) . - p. 10-22 Titre : Identification of slightly halophilic bacteria from salted sheepskin samples and investigation of their biotechnological importance Type de document : texte imprimé Auteurs : Dilek Yalcin, Auteur ; Pinar Caglayan, Auteur ; Didem Berber, Auteur Année de publication : 2024 Article en page(s) : p. 10-22 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Antimicrobiens Bactéries -- Identification Bactéries halophiles Bactériocines Les bactériocines sont une famille de peptides ou protéines synthétisés naturellement par certaines bactéries. Une bactériocine consiste généralement en un composé protéique de 20 à 60 acides aminés. Les bactériocines ne sont pas des antibiotiques mais elles possèdent des propriétés antibiotiques : - Elles peuvent être bactériocides, c'est-à-dire éliminer certains micro-organismes. - Elles peuvent être bactériostatiques, c'est-à-dire inhiber la croissance de certains micro-organismes. Cuirs et peaux de moutons Diéthyldithiocarbamate de sodium Enzymes microbiennes Peaux salées Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In the leather industry, skins/hides are salted immediately after the animal is slaughtered to prevent the enzymatic activities of bacteria. Although the salt-curing method prevents the growth of mesophilic bacteria, halophilic bacteria can develop in skins/hides that are stored for a long time, causing a decrease in leather quality. In the literature, it has been stated that slightly halophilic bacteria are isolated from products with a certain concentration of salt content. Since there is no study on the presence of these bacteria in salted raw hides, slightly halophilic bacteria were isolated and molecularly identified from ten sheepskin samples which were stored at 20°C for 6 months in our study. Also their biotechnologically important enzymes were evaluated, their bacteriocin production capacity was determined and the antibacterial efficacy of a chemical (sodium dimethyldithiocarbamate) used in the leather industry at certain concentrations were tested against these isolates. The total number of slightly halophilic bacteria, the total number of proteolytic slightly halophilic bacteria and the total number of lipolytic slightly halophilic bacteria in skin samples were determined as 1 x 104 – 4 x 105CFU/g, 2 x 103 – 4 x 104CFU/g and 1 x 102 – 3 x 104CFU/g, respectively. A total of 20 slightly halophilic bacteria were isolated from skin samples. Gram-positive and rod-shaped isolates showed optimum growth at 3-5% salt, 37°C-45°C and pH7-8. Protease, lipase, DNase, pullulanase, xylanase and cellulase produced by 100%, 61%, 83%, 11%, 44%, 88% isolates, respectively. In addition, oxidase and catalase activities were detected in all isolates. It has been determined that the isolates were able to produce acids from different sugar sources (D-xylose, D-mannose, D-ribose, sucrose) and can use amino acids (L-cysteine, L-glycine, L-alanine, L-threonine) found in the skin’s structure. According to the 16S rRNA sequence analysis results, the isolates belonged to the Bacillus genus (B. rugosus, B. amyloliquefaciens, B. haynesii, B. aerius, B. safensis, B. pumilus, B. kochii, B. mojavensis and B. atrophaeus). Among all isolates producing bacteriocin, the bacteriocin produced by Bacillus aerius had a thermostable structure, did not lose its activity at high pH and salt values, completely inactivated its activity when treated with proteinase K enzyme, and had its antibacterial activity when treated with lipase enzyme. Therefore, considering that some species are resistant to antimicrobials, purified bacteriocins can be used as a preservative in the leather industry. The isolates were sensitive to tested chemical substance at a certain concentrations (4000, 2000, 1000, 500, 250, 125, 62.5, 31.2, 15.6, 7.8μg/mL) and minimum inhibitory concentration (MIC) were detected. The MIC values of the isolates were determined as as 62.5μg/mL (B. rugosus), 31.2μg/mL (B. haynesii, B. safensis, B. mojavensis) 15.6μg/mL (B. amyloliquefaciens, B. aerius, B. kochii) 7.8μg/mL (B. pumilus) and 3.9μg/mL (B. atrophaeus). In this way, unnecessary use of chemicals in the soaking process will be prevented. Note de contenu : - Collection of salted sheepskin samples - Total number of slightly halophilic bacteria and isolation process - Detection of total numbers of proteolytic and lipolytic slightly halophilic bacteria - Determination of salt concentrations, temperatures and pH values for each isolate - Enzymatic activity tests of isolates - Biochemical tests of isolates - Molecular identification - Investigation of bacteriocin production capabilities of slightly nalophilic bacteria - Effects of different environmental conditions on bacteriocin activity - Determination of susceptibility of isolated slightly halophilic bacteria to antimicrobial agent by disk diffusion method - Table 1 : The total number of slightly halophilic bacteria, proteolytic slightly halophilic bacteria and lipolytic slightly halophilic bacteria in sheepskin samples (CFU/g) - Table 2 : Salt concentration, pH and temperature range results in which slightly halophilic bacteria isolates can grow - Table 3 : Isolate codes, base length (bp), similarity rate (%), phylogenetically similar species and accession numbers of slightly halophilic bacteria isolates - Table 4 : Frequency of slightly halophilic bacteria isolates in salted sheepskins - Table 5 : Biochemical characteristics and enzymatic activity results of isolates - Table 6 : Bacteriocin production of slightly halophilic bacterial isolates against each other - Table 7 : Determining optimum environmental conditions for bacteriocin activity - Table 8 : Antimicrobial effect of tested antimicrobial agent against isolates of slightly halophilic bacteria B. haynesii B. rugosus B. safensis B. mojavensis B. atrophaeus B. amyloliquefaciens B. aerius En ligne : https://drive.google.com/file/d/1rqhgvBtB4BA4cbuNl03NaM2VE62-SqSR/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40928 [article]

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