Detoxification of enterotoxigenic Bacillus cereus (JX455159) isolated from meat by a local strain of Lactobacillus plantarum (JX282192)

2013 ◽  
Vol 64 (1) ◽  
pp. 287-296 ◽  
Author(s):  
Fifi M. Reda
2019 ◽  
Vol 26 (4) ◽  
pp. 535-542 ◽  
Author(s):  
Juana Inés Machuca-Guevara ◽  
Erick Antonio Suárez-Peña ◽  
Emmerik Motte Darricau ◽  
Eric Louis Mialhe-Matonnier

La fermentación de granos de cacao es un proceso espontáneo de post cosecha muy importante para el desarrollo de aroma y sabor a chocolate el cual involucra un sin número de actividades microbianas complejas. En el presente estudio se identifican los microorganismos presentes en granos de cacao antes, durante y después del proceso de fermentación aplicando dos métodos: el análisis de secuenciamiento de ADN y la espectrometría de masas MALDI TOF/TOF. Dentro del grupo de bacterias y levaduras predominantes identificadas por el primer método se encontro a Lactobacillus plantarum (29%), L. brevis (18%), Bacillus cereus (15%), Pediococcus acidilactici (12%), y Pichia kudriavzevii (100%). Asimismo se caracterizó por huella de masas las secuencias peptídicas más importantes de cada cepa identificada. Por otro lado, aplicando el segundo método, se identificaron 57 especies de microorganismos, siendo el 73.7% especies bacterianas y el 26.3% especies de levaduras. Adicionalmente se detectaron secuencias peptídicas de la proteína vicilina responsable del aroma característico de los granos de cacao fermentados y a la proteína albumina de 21KDa.


Author(s):  
Abiola Abiodun Bayode ◽  
Ojokoh, Anthony Okhonlaye

Gari’ is consumed regularly by large populations of Nigeria, therefore, it is an excellent means of improving the diet of people through fortification with nutritionally rich foods hence, this study aim to produce ‘Gari’ by co-fermenting cassava mash and sprouted mung bean flour in different ratios in order to assess the effect on the nutritional composition as compared to a standard produced without sprouted mungbeans (SMF) flour fortification. In different ratios, composites of cassava mash (CM) and the sprouted mungbeans flour (SMF) were made (5% SMF + 95% CM, 10% SMF + 90% CM, 15% SMF + 85% CM; and 100% CM which serve as the control) and fermented using semi-solid state fermentation for four days. The Gari was then produced following the standard method of dewatering, sieving and roasting. Isolation of microorganism during the fermentation was carried out using standard microbiological techniques and identification was done using conventional and molecular techniques. The total bacterial (cfu/ml) of the fermented samples increased during the first day of fermentation, and reduced on subsequent days in all samples with the bacterial count ranging from 1.21 x105 CFU/g to 2.45 x105 CFU/g. The organisms isolated include Lysinibacillus alkalisoli, Proteus mirabilis, Pediococcus acidilactici, Lactobacillus plantarum, Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Penicillium sclerotiorum, Diutina catenulate, Rhizopus stolonifer, Trichoderma viridae, Saccharomyces cerevisiae. Most of the organisms isolated during the first and second day of fermentation such as Proteus spp, Staphylococcus spp, Bacillus spp, Bacillus spp, Diutina spp and Trichoderma spp, later disappeared toward the later days of the fermentation. Lactic acid bacteria, mold and yeast isolates such as Lactobacillus plantarum, Pediococcus spp. Penicillium spp and Saccharomyces cerevisiae dominate toward the later stage of the fermentation in all the fermented samples. Molecular identification of the bacterial isolates shows that Lysinibacillus alkalisoli, Proteus mirabilis, Pediococcus acidilactici, Lactobacillus plantarum, Staphylococcus aureus, Bacillus subtilis and Bacillus cereus were present in the samples. The outcome of this research showed that co-fermentation of cassava mash and sprouted mung bean flour eliminates pathogenic microorganisms and encourages the growth of beneficial microorganism in mung bean fortified Gari production.


2021 ◽  
Vol 10 (4) ◽  
pp. 857-863
Author(s):  
Enny Ratnaningsih ◽  
Rachmad Ade ◽  
Rindia Maharani Putri ◽  
Idris Idris

In recent years, attention to microbial dehalogenase has continually increased due to its potential application, both in bioremediation and in the biosynthesis of fine chemicals. Many microbial recombinant strains carrying dehalogenase gene have been developed, particularly to increase the dehalogenase production and its quality. In this study, we aimed to find the optimum condition for the production of active haloacid dehalogenase by E. coli BL21 (DE3) harboring recombinant plasmid pET-bcfd1 that carried haloacid dehalogenase gene from Bacillus cereus IndB1 local strain. This would be examined by assessing the ability of whole cell life culture to degrade monochloroacetic acid (MCA) and quantifying the chloride ion released into the medium. Several variables were evaluated to find this optimal condition. We found that the best condition for MCA biodegradation using this recombinant clone was at 0.2 mM MCA, 10 μM of isopropyl β-D-1-thiogalactopyranoside (IPTG), 6 hours of pre-induction incubation at 37ºC with shaking, 2 hours IPTG induction at 30ºC with shaking, at pH 7 in Luria Bertani (LB) liquid medium without NaCl, which produced about 0.056 mM chloride ions. Inducer concentration, pre-induction incubation time and temperature, as well as induction time and temperature were apparent to be associated with the expression of the protein, while the MCA concentration and the pH of the medium influenced the ability of the recombinant E. coli BL21 (DE3)/pET-bcfd1 to grow in toxic environment. Our findings laid the foundation for exploration of dehalogenases from local Bacillus strains through genetic engineering for MCA biodegradation


Author(s):  
F. Louchet ◽  
L.P. Kubin

Investigation of frictional forces -Experimental techniques and working conditions in the high voltage electron microscope have already been described (1). Care has been taken in order to minimize both surface and radiation effects under deformation conditions.Dislocation densities and velocities are measured on the records of the deformation. It can be noticed that mobile dislocation densities can be far below the total dislocation density in the operative system. The local strain-rate can be deduced from these measurements. The local flow stresses are deduced from the curvature radii of the dislocations when the local strain-rate reaches the values of ∿ 10-4 s-1.For a straight screw segment of length L moving by double-kink nucleation between two pinning points, the velocity is :where ΔG(τ) is the activation energy and lc the critical length for double-kink nucleation. The term L/lc takes into account the number of simultaneous attempts for double-kink nucleation on the dislocation line.


Author(s):  
Joanna L. Batstone

Interest in II-VI semiconductors centres around optoelectronic device applications. The wide band gap II-VI semiconductors such as ZnS, ZnSe and ZnTe have been used in lasers and electroluminescent displays yielding room temperature blue luminescence. The narrow gap II-VI semiconductors such as CdTe and HgxCd1-x Te are currently used for infrared detectors, where the band gap can be varied continuously by changing the alloy composition x.Two major sources of precipitation can be identified in II-VI materials; (i) dopant introduction leading to local variations in concentration and subsequent precipitation and (ii) Te precipitation in ZnTe, CdTe and HgCdTe due to native point defects which arise from problems associated with stoichiometry control during crystal growth. Precipitation is observed in both bulk crystal growth and epitaxial growth and is frequently associated with segregation and precipitation at dislocations and grain boundaries. Precipitation has been observed using transmission electron microscopy (TEM) which is sensitive to local strain fields around inclusions.


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