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A recombinant Bacillus subtilis strain containing a plasmid encoding a luxAB fusion, which gave bioluminescence upon addition of an exogenous long-chain aldehyde as substrate for the endogenous luciferase enzyme, was used as test organism. Its populations were treated with 300 MPa for 20 min, or 600 MPa for 20 min at around room temperature, and this treatment is foreseen as a quality-friendly, non-thermal pasteurisation of foods. Besides the estimation of viable cell counts, the extent of pressure-induced germination and post-process development were investigated by phase-contrast microscopy, turbidimetry and luminometry. Increased heat sensitivity of pressurized spore populations was observed both by viable cell counting during a linearly programmed elevation of temperature and a simultaneous differential scanning calorimetry. This was related to pressure-induced germination of spores, although a small fraction remained ungerminated. The luciferase pool built into the spores during their formation seemed to have withstood pressurization. Spore germination was accompanied by the emergence of bioluminescence which also indicated sensitively the characteristic changes of metabolic activity running parallel with the development of untreated cell populations and that of the survivors of the hydrostatic pressure treatments when the cells were incubated in a nutrient broth.

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Acta Biologica Hungarica
Authors:
Wesam I. A. Saber
,
Khalid M. Ghoneem
,
Abdulaziz A. Al-Askar
,
Younes M. Rashad
,
Abeer A. Ali
, and
Ehsan M. Rashad

purification of chitinase from Bacillus subtilis . World J. Exp. Biosci. 1 , 5 – 9 . 6. Galeazzi , M. A. M. , Sgarbieri , V. C. , Constantides , S. M. ( 1981 ) Isolation

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., Schanck, K., Colson, C. (1993) Purification and preliminary characterization of the extracellular lipase of Bacillus subtilis 168, an extremely basic pH-tolerant enzyme. Eur. J. Biochem. 216 , 155

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Acta Alimentaria
Authors:
J. A. Grahovac
,
Z. Z. Rončević
,
I. Ž. Tadijan
,
A. I. Jokić
, and
J. M. Dodić

Bacillus subtilis is one of the most important producers of diverse antimicrobial compounds. This bacterium grows and produces antibiotics on different substrates. The increase of the antibiotics yield can be achieved by changing the conditions of cultivation and the composition of the culture media. In this study, response surface methodology was used for optimization of glycerol, sodium nitrite, and phosphate content in media for production of antibiotics effective against Staphylococcus aureus. As biosynthesis strain Bacillus subtilis ATCC 6633 was used. The developed model predicts that the maximum inhibition zone radius (38.08 mm) against Staphylococcus aureus and minimal amount of residual nutrients (glycerol 1.75 g l−1, nitrogen 0.21 g l−1, phosphorus 0.18 g l−1) are achieved, when the initial content of glycerol, sodium nitrite, and phosphate are 49.99 g l−1, 1.00 g l−1, and 5.00 g l−1, respectively.

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Bacillus subtilis natto is a potential source of fructooligosaccharides (FOS), which can be obtained by fermentation and may stimulate the growth of beneficial microorganisms in the colon representing a strategy to manipulate the intestinal microbiota acting as a prebiotic compound. The present study focuses on the ability of Lactobacillus ssp. strains to utilize FOS as a sole energy source. The results showed that FOS was equally good as glucose to provide energy source. The highest prebiotic activity score was obtained with Lactobacillus plantarum ATCC 14917 grown on FOS (0.526), followed by Lactobacillus casei (LC-1) (0.222). The lowest score was for Lactobacillus paracasei ATCC 27092 (−0.051). The results suggests that specific combinations of probiotic (L. plantarum ATCC 14917 and L. casei (LC-1)) and prebiotic (FOS) could be used as synbiotics in dairy and other foods.

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The effect of four rhizobacterial strains on the severity of spot blotch disease caused by cochliobolus sativus was evaluated for two growing seasons under rainfed conditions. Three barley genotypes were used as host plant. All strains reduced C. sativus severity, with effect more pronounced when Pseudomonas putida BTP1 and Bacillus subtilis Bs2508 were used. The disease reduction was up to 56% in Arabi Abiad / P. putida BTP1. The grain yield was not obviously affected by the presence of the rhizobacteria, except some signifitive increase in season 2. Raising the resistance by soaking seed with rhizobacterial strains might be of ultimate value in agriculture.

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Menaquinone-7 (MK-7) is a type of vitamin K. MK-7 is produced via bacterial fermentation, and in order to reach the desired product purity, several downstream processing steps, including extraction, drying, ultrasonication, must be carried out. These processes, however, need to be carried out in such fashion to ensure the least amount of vitamin K lost and maximum recovery into the end-product. Therefore, in this study, drying, storage at 4 and −20 °C, and ultrasonication steps were evaluated under different conditions. Static liquid fermentations were conducted in McCartney bottles to explore the maximum MK-7 secretion potentials in different glycerol and glucose-based media compositions that were optimized in our previous studies. Maximum 32.5±0.4 mg l−1 and 14.6±0.4 mg l−1 concentrations were achieved in glycerol and glucose-based media, respectively. Concentrations of MK-7 produced under same fermentation conditions in 30 ml McCartney amber bottles with 3 ml of media in them and in 75 ml culture tubes with 20 ml media were compared. Also, ultrasonication, drying, and storage conditions were investigated to ensure the least amount of vitamin K is lost. Results showed that drying under forced air flow was the fastest, thus, demonstrated a better preservation of the vitamin, and should replace vacuum drying. Ultrasonication for 15 min seems to be safe and sufficient for phase transition for analysis. Also, storage at refrigerated temperatures seems to preserve MK-7 at least for one week. Furthermore, fermentations in McCartney bottles indicated how MK-7 concentrations are distributed in different zones of the static liquid broth. Culture tube results provided the conclusion as of how the metabolism of MK-7 changes in static fermentation when the scale-up process begins from McCartney bottle to culture tubes. Results in general showed a clearer road map to ensuring better quality and preservation of the valuable end-product, and illuminated more the path to further scaling up of the fermentation process for commercial production of MK-7.

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– 1801 . C HANTAWANNAKUL , P. , O NCHAROAN , A. , K LANBUT , K. , C HUKEATIROTE , E. & L UMYONG , S. ( 2002 ): Characterization of protease of Bacillus subtilis strain 38

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Extracts of five Euphorbia species were studied for their activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Candida albicans. E. amygdaloides and E. helioscopia proved to be the most effective against them. Some plant metabolits were also examinated against the microorganisms: podophyllin and rhamnetin caused the greatest, b-sitosterine the smallest inhibition among them. Bacillus subtilis was the least sensitive among the studied microorganism in this study.

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Clinical and Laboratory Standard Institute ( CLSI, 2018 ). Standard strains of E. coli ATCC 35218, S. aureus ATCC 25923, Bacillus cereus CCM 2010 and Bacillus subtilis WDCM 00003 were used. Bacterial cells were harvested in the logarithmic phase of

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