Determination of foodborne pathogens in minced beef by real-time PCR without culture enrichment.

Meat provides the necessary environment for the growth of foodborne pathogens due to its features such as being rich in protein and having sufficient water activity. Listeria monocytogenes, Salmonella enterica, and Escherichia coli O157:H7, which can be transmitted through many foods, including water, and cause serious diseases, are among the significant pathogens. In the current study. Detection of Listeria monocytogenes, Escherichia coli and Salmonella enterica in 100 minced beef samples collected from different butchers and markets situated in the central districts of Erzurum province was performed by Real-Time PCR without pre-enrichment and DNA isolation. Linear regression equations of Ct values of standard pathogenic bacteria were created. Ct values of minced beef samples obtained as a result of Real-Time PCR analysis were substituted in the equations, and the amounts of pathogenic bacteria in the samples were determined. Listeria monocytogenes, Escherichia coli, and Salmonella enterica were detected in 45, 30, and 29 of 100 minced beef samples, respectively. It is known that the Real-Time PCR method, which is used to detect pathogenic bacteria, is more specific, fast, and reliable than conventional methods. According to the results obtained, it has been clearly observed that with our new approach, pathogenic bacteria growing on foods can be detected sensitively with less cost, shorter amount of time, and minimized workload without pre-enrichment and DNA isolation.

Production of Endoglucanase by Exiguobacterium mexicanum OB24 Using Waste Melon Peels as Substrate.

Millions of tons of agricultural waste are produced globally every year. A practical solution to this global problem is to convert this waste into value-added products. In this study, endoglucanase enzyme production was carried out by using waste melon peels as a carbon source. To use this important resource, its stubborn structure must be broken down. Rumen bacteria are regarded as unique for this job. Therefore, firstly endoglucanase producing rumen bacteria was isolated and the bacteria with the best activity (OB24) were identified by molecular methods (16S rRNA gene squencing). As a result of the sequence analysis, it was determined that isolate belonged to Exiguobacterium mexicanum. Then, by optimizing the culture conditions, the enzyme production potential was increased. The optimal conditions were determined as 50 g/L MPP, 2g/L yeast extract, 60 h incubation time, pH: 6.0, and 40°C temperature. Under optimized conditions the enzyme activity increased approximately 3.8-fold.

Bacillus pasinlerensis sp. nov., a thermophilic bacterium isolated from a hot spring in Turkey.

A Gram-reaction-positive, endospore-forming bacterium, designated strain P1T, was isolated from water samples collected from Pasinler Hot Spring and characterized using a polyphasic approach to clarify its taxonomic position. Strain P1T was found to have chemotaxonomic and morphological characteristics consistent with its classification in the genus Bacillus. The strain shared the highest 16S rRNA gene sequence identity values with Bacillus thermolactis R-6488T (97.6 %) and Bacillus kokeshiiformis MO-04T (97.2 %) and formed a distinct clade with both type strains in the phylogenetic trees based on 16S rRNA gene sequences. Strain P1T could grow optimally at 55 °C and in the presence of 2 % NaCl. The organism was found to contain meso-diaminopimelic acid as the diagnostic diamino acid in the cell-wall peptidoglycan. The major polar lipids were diphosphatidylglycerol and phosphatidylglycerol. The predominant menaquinone was determined to be MK-7. The major cellular fatty acids were identified as iso-C15 : 0, iso-C17 : 0 and anteiso-C17 : 0. Based upon the consensus of phenotypic and phylogenetic analyses, strain P1T represents a novel species of the genus Bacillus, for which the name Bacillus pasinlerensis sp. nov. is proposed. The type strain is P1T (=DSM 107529T=CECT 9885T=NCCB 100674T).

A novel endo-ß-1,4-xylanase from Pediococcus acidilactici GC25; purification, characterization and application in clarification of fruit juices.

A novel extracellular xylanase was purified and characterized from Pediococcus acidilactici GC25 (GenBank number: MF289522). The purification was 4.6-fold with a yield of 43.61% through acetone precipitation, Q-Sepharose, and CM-Sepharose ion change chromatography. The molecular weight of the enzyme was 48.15 kDa, and the optimum pH and temperature were 7.0 and 40 °C, respectively. The maximum activity was observed between 20 and 50 °C. Although it was active within a wide pH range (pH 2.0-9.0), it retained over 85% of its activity after 24 h incubation; and over 70% of its activity after 168 h incubation in neutral and alkaline pH. It was observed that the enzyme showed high stability with K+, Ba2+, Cd2+, Co2+, Sr2+, Mg2+, Ca2+, Al3+, Zn2+, and Ni2+ ions. The Km and Vmax for the xylanase were 3.10 mg mL-1 and 4.66 U/mg protein, respectively. It was determined that treatment of different fruit juices with P. acidilactici GC25 xylanase improved the clarification. The highest increase in the reducing sugar amount and decrease in the turbidity was 24.47 ±â€¯1.08 and 21.22 ±â€¯0.58 for peach juice at 0.15 U/mL enzyme concentration. These results showed that the xylanase purified from P. acidilactici GC25 may have a wide potential in biotechnological processes of the food and baking industry.

New xylanolytic enzyme from Geobacillus galactosidasius BS61 from a geothermal resource in Turkey.

In this study, isolation, conventional and molecular characterizations of ten thermophilic bacteria from Rize/Ayder were carried out. Xylanase from Geobacillus galactosidasius BS61 (GenBank number: KX447660) was purified by acetone precipitation, Diethylaminoethyl-cellulose and Sephadex G-100 chromatographies. The xylanase of G. galactosidasius BS61 in clarifying fruit juice was also investigated. Enzyme was purified 29.80-fold with 75.18% yield; and molecular weight was determined as 78.15 kDa. The optimum temperature of xylanase was 60 °C. The enzyme activity was maintained fully after 24 h and over 50% after 168 h at pH 4.0-10.0, while optimum pH was 7.0. Km and Vmax for beech wood xylan were measured as 3.18 mg mL-1, 123 U mg protein-1. In addition, Ca2+, Na+, Al3+, Zn2+, Cd2+, Mg2+, Ni2+, Cu2+ had decreasing effect on enzyme activity, while enzyme activity had been protected against anions, especially HSO3- and HPO42- stimulated enzyme activity. Xylanase applications (with 15 U/mL enzyme activity) in orange and pomegranate juices were increased; and the sugar and turbidity amounts were reduced 17.36% ±â€¯1.18 and 30.52 ±â€¯1.23, respectively. These results indicated that the xylanase of G. galactosidasius BS61 has biotechnological potential in juice clarification due to its stability against metal ions, chemicals and high pH-values.

Purification and biochemical characterization of a novel thermostable serine alkaline protease from Aeribacillus pallidus C10: a potential additive for detergents.

An extracellular thermostable alkaline serine protease enzyme from Aeribacillus pallidus C10 (GenBank No: KC333049), was purified 4.85 and 17. 32-fold with a yield of 26.9 and 19.56%, respectively, through DE52 anion exchange and Probond affinity chromatography. The molecular mass of the enzyme was determined through sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), with approximately 38.35 kDa. The enzyme exhibited optimum activity at pH 9 and at temperature 60 °C. It was determined that the enzyme had remained stable at the range of pH 7.0-10.0, and that it had preserved more than 80% of its activity at a broad temperature range (20-80 °C). The enzyme activity was found to retain more than 70% and 55% in the presence of organic solvents and commercial detergents, respectively. In addition, it was observed that the enzyme activity had increased in the presence of 5% SDS. KM and Vmax values were calculated as 0.197 mg/mL and 7.29 µmol.mL-1.min-1, respectively.

Purification and characterization of [Formula: see text]-mannanase from Bacillus pumilus (M27) and its applications in some fruit juices.

Thermo alkaline mannanase was purified from the bacteria of Bacillus pumilus (M27) using the techniques of ammonium sulphate precipitation, DEAE-Sephadex ion exchange chromatography and Sephacryl S200 gel filtration chromatography with 111-fold and 36 % yield. It was determined that the enzyme had 2 sub-units including 35 kDa and 55 kDa in gel filtration chromatography and SDS-PAGE electrophoresis systems. The optimum pH and temperature was determined as 8 and 60 °C, respectively. It was also noticed that the enzyme did not lose its activity at a wide interval such as pH 3-11 and at high temperatures such as 90 °C. Additionally, the effects of some metal ions on the mannanase enzyme activity. Moreover, the clarifying efficiency of purified mannanase enzyme with some fruit juices such as orange, apricot, grape and apple was also investigated. Enzymatic treatment was carried out with 1 mL L(-1) of purified mannanase for 1 h at 60 °C. It was determined that the highest pure enzyme was efficient upon clarifying the apple juice at 154 % rate.