proteolytic fermentation
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Microbial and enzymatic degradation of keratin waste is more preferred over various conventional approaches which are costly and not environmentally suitable. Diverse niches are auspicious for the discovery of new microorganisms. To discover novel keratinolytic bacteria, 60 isolates from different poultry dumping sites were initially screened, and among these found a potent keratinolytic isolate (NKSP-7) that displayed higher feather-degrading ability. The selected isolate was identified as Bacillus sp. NKSP-7 based on 16S rDNA sequencing as well as physiochemical and morphological characteristics. The strain NKSP-7 showed complete hydrolysis of native chicken feathers (10 g/L) in nutrient medium after 24 h of incubation at 37 °C under agitation (150 rev/min) and produced thermostable extracellular keratinase. The crude enzyme displayed maximal keratinolytic activity (34.7 U/mL) in phosphate buffer of pH 7.0, and at 60 °C using keratin azure as a substrate. Keratinolytic enzyme showed stability at 20-65 °C for 4 h over the pH range of 5.5-8.0. No obvious inhibitory influence was perceived by cations, organic solvents, EDTA, and detergents. Whereas, enzyme activity was enhanced by adding β-mercaptoethanol, Na+, Cd2+, and Mn2+. All these notable features of keratinase make it a promising candidate for various industrial applications especially for dehairing process in leather industry, bioconversion of poultry waste, and in detergents formulations.
- MeSH
- Bacillus klasifikace genetika izolace a purifikace metabolismus MeSH
- bakteriální proteiny chemie genetika metabolismus MeSH
- biodegradace MeSH
- drůbež * MeSH
- fermentace MeSH
- keratiny analýza metabolismus MeSH
- koncentrace vodíkových iontů MeSH
- kur domácí MeSH
- molekulová hmotnost MeSH
- odpadky - odstraňování metody MeSH
- peří chemie metabolismus MeSH
- proteasy chemie genetika metabolismus MeSH
- proteolýza MeSH
- RNA ribozomální 16S genetika MeSH
- teplota MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Bacillus licheniformis HJ4 showing strong fibrinolytic activity was isolated from Hwangseokae jeotgal. aprEHJ4, a major fibrinolytic gene, was cloned by PCR, and an ORF consisting of 379 amino acids was located. The mature enzyme was expected to be 27 kDa in size after processing, but a 24-kDa protein was observed by SDS-PAGE and fibrin zymography, indicating additional processing. RT-qPCR showed that expression level of aprEHJ4 in culture with 0% salt (control) was the highest followed by culture with 8% salt (89.7% of control) and 5% salt (74.2%) at 84 h. The expression level in culture with 15% salt was 46.9%. The results matched with the fibrinolytic activity measurements of cultures and indicated that AprEHJ4 maintained significant activity in the presence of salt up to 15% (w/v). AprEHJ4 was overproduced in Escherichia coli, and mature 27 kDa protein was purified after in vitro renaturation. The optimum pH and temperature of AprEHJ4 were pH 8 and 40 ℃, respectively.
- MeSH
- aktivace enzymů účinky léků MeSH
- Bacillus licheniformis * enzymologie MeSH
- chlorid sodný farmakologie MeSH
- fermentované potraviny * mikrobiologie MeSH
- koncentrace vodíkových iontů MeSH
- potrava z moře (živočišná) * mikrobiologie MeSH
- proteasy metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Korejská republika MeSH
- MeSH
- alfa-1-antitrypsin krev MeSH
- celková kapacita plic MeSH
- detergenty * škodlivé účinky MeSH
- hygiena práce MeSH
- imunoglobuliny krev MeSH
- izoenzymy krev MeSH
- lidé MeSH
- nemoci dýchací soustavy epidemiologie etiologie MeSH
- prach MeSH
- pracoviště MeSH
- pracovní expozice statistika a číselné údaje škodlivé účinky MeSH
- proteasy škodlivé účinky MeSH
- subtilisiny škodlivé účinky MeSH
- zdravotní stav MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- klinická studie MeSH
- MeSH
- amylasy analýza MeSH
- fermentace fyziologie MeSH
- jedlé rostliny MeSH
- potravinářská mikrobiologie normy MeSH
- proteasy analýza MeSH
- Geografické názvy
- Nigérie MeSH
Tato studie se zaobírá posouzením technologických vlastností a probiotického potenciálu původních bakterií St. thermophilus R4 a R14 izolovaných z tradičního alžírského fermentovaného mléka nazývaného “Raib”. Výsledky ukazují, že tyto lokální kmeny produkují kyselinu rychleji, mají dobrou proteolytickou aktivitu, produkují exopolysacharidy a jsou dobrými antagonisty. Výsledky probiotických vlastností ukazují, že tyto kmeny jsou schopné přežít v pH 2.5 a v 0.3 % žlučové kyselině s dobrou adherence na epiteliální buňky. Dále vykazují dobrou viabilitu v simulovaném gastrointestinálním prostředí. Výsledky “cross-streak” testu prokázaly nepřítomnost antagonistické aktivity a potvrdil kompatibilitu mezi těmito kmeny a komerčními Lb. delbrueckii subsp bulgaricus. Testované kmeny vykazují in vitro žádoucí probiotické vlastnosti a jsou vhodnými kandidáty pro jejich použití jako probiotika v potravinářském průmyslu. Keywords: probiotika, Streptococcus thermophilus, tradiční potraviny
This study aimed to assessing the technological traits and probiotic potential of autochthonous St. thermophilus R4 and R14 isolated from Algerian traditional fermented milk cold “Raib”. The results showed that these local strains were fastest acid producing, have good proteolytic activity, have the ability to produce exopolysaccharides and exhibited good antagonistic activity. The results of the probiotic properties showed that these strains were able to survive at pH 2.5 and 0.3 % bile with a good adherence to epithelial cells. These strains showed a good viable count in simulated gastrointestinal juice. The results of cross-streak test showed the absence of antagonistic activity and confirmed the compatibility between these strains and a commercial Lb. delbrueckii subsp bulgaricus. The tested strains were found in vitro possess desirable probiotic properties and they are good candidates for their application as probiotic starter in the food industry. For the Algerian yogurt industry, potential St. thermophilus strains able to be used as starter in combination with other local Lb. delbrueckii subsp bulgaricus may be found.
In the present study, the evolution of the physicochemical and microbiological characteristics of lactic acid bacteria (LAB) in traditional Kırklareli white brined cheese collected from 14 different cheese manufacturing facilities were investigated on different days of the 90-day ripening period. The obtained LAB within the species Lactococcus (Lc.) lactis, Latilactobacillus (Lt.) curvatus, Lactobacillus (Lb.) casei and Lb. plantarum, Enterococcus (E.) durans, E. faecium, E. faecalis, Streptococcus macedonicus, and Weissella paramesenteroides were characterized in terms of their influence on technological properties and their potential as starter cultures for traditional white brined cheese production. The results of the microbiological and physicochemical investigations showed that a few selected isolates of Lc. lactis, Lb. casei, and Lb. plantarum had certain functions as starter germs. Moderate acidification capacity, antibacterial activity and proteolytic activity, which are characteristic of their use as starter lactic acid bacteria, were found. Importantly, antibiotic resistance among selected Lc. lactis, Lb. casei, and Lb. plantarum isolates was extremely low, whereas some of these isolates demonstrated antibacterial activity against major foodborne pathogenic bacteria. Based on the results obtained in this study, selected Lc. and Lb. isolates can also be considered as starter culture in traditional cheese production.
Twenty-two Brevibacterium linens strains isolated from 'Pecorino di Filiano' cheese ripened in two different environments (natural cave and storeroom) were characterized and differentiated for features of technological interest and by genotypic methods, in order to select strains with specific features to be used as surface starter cultures. Results showed significant differences among strains on the basis of physiological and technological features, indicating heterogeneity within the species. A middle-low level of proteolytic activity was observed in 27.3 % of strains, while a small group (9.1 %) showed a high ability. Lipolytic activity was observed at three different temperatures and the highest value was detected at 20 °C with 13.6 % of strains, while an increase in temperature produced a slightly lower lipolysis in all strains. The evaluation of diacetyl production revealed that only 22.8 % of strains showed this ability, and most of them were isolated from product ripened in the natural cave. All strains exhibited only leu-aminopeptidase activity, with values more elevated in strains coming from the natural cave product. The combined analysis of genotypic results with the data obtained by the features of technological interest study established that the random amplified polymorphic DNA (RAPD) clusters obtained were composed not only of different genotypes but of different profiles based on technological properties too. This study demonstrated the importance of the ripening environment that affects the typical features of the artisanal product, leading to the selection of a specific surface microflora. Characterized strains could be associated within surface starters to standardize the production process of cheese, but preserving its typical organoleptic and sensory characteristics and improving the quality of the final product.
- MeSH
- bakteriální proteiny metabolismus MeSH
- Brevibacterium enzymologie genetika izolace a purifikace metabolismus MeSH
- fermentace MeSH
- genotyp MeSH
- mikrobiologie životního prostředí MeSH
- mléko mikrobiologie MeSH
- potravinářská mikrobiologie * přístrojové vybavení metody MeSH
- skot MeSH
- sýr mikrobiologie MeSH
- životní prostředí MeSH
- zvířata MeSH
- Check Tag
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Fecal microbiota transfer may serve as a therapeutic tool for treating obesity and related disorders but currently, there is no consensus regarding the optimal donor characteristics. We studied how microbiota from vegan donors, who exhibit a low incidence of non-communicable diseases, impact on metabolic effects of an obesogenic diet and the potential role of dietary inulin in mediating these effects. Ex-germ-free animals were colonized with human vegan microbiota and fed a standard or Western-type diet (WD) with or without inulin supplementation. Despite the colonization with vegan microbiota, WD induced excessive weight gain, impaired glucose metabolism, insulin resistance, and liver steatosis. However, supplementation with inulin reversed steatosis and improved glucose homeostasis. In contrast, inulin did not affect WD-induced metabolic changes in non-humanized conventional mice. In vegan microbiota-colonized mice, inulin supplementation resulted in a significant change in gut microbiota composition and its metabolic performance, inducing the shift from proteolytic towards saccharolytic fermentation (decrease of sulfur-containing compounds, increase of SCFA). We found that (i) vegan microbiota alone does not protect against adverse effects of WD; and (ii) supplementation with inulin reversed steatosis and normalized glucose metabolism. This phenomenon is associated with the shift in microbiota composition and accentuation of saccharolytic fermentation at the expense of proteolytic fermentation.
- MeSH
- fekální transplantace MeSH
- glukosa farmakologie MeSH
- inulin farmakologie MeSH
- lidé MeSH
- myši MeSH
- potravní vláknina farmakologie MeSH
- střevní mikroflóra * MeSH
- vegani MeSH
- západní dieta MeSH
- ztučnělá játra * prevence a kontrola farmakoterapie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
