Species of the genus Streptomyces produce antibiotics and grow on sub- strates with a different carbon and nitrogen source. The increase of the yield of antibiotics can be achieved at an early stage ...of the investigation by changing the conditions of fermentation and the composition of the culture medium. During the production process of biodiesel by transesterification of plant oil, except for the target product the raw glycerol in relatively large amounts (10% of the input quantities of oil) is obtained. Glycerol generated in the alkali-cat- alyzed transesterification reaction can be regarded as crude fraction because besides glycerol, there are also traces of soap and dirt from the oil and catalyst residues. The possibility of the production of antibiotics by growing the cultures Streptomyces hygroscopicus CH-7 on the medium containing glycerol as the carbon source was studied in this work. The antibiotics production with crude glycerol remaining from the biodiesel production process from sunflower oil and rape seed oil was monitored under laboratory conditions. The yield of the produced antibiotics hexaene (H-85) and azalomycine and the glycerol con- centration change were followed during the fermentation. The waste glycerol from the biodiesel production from rapeseed oil proved to be the least suit- able carbon source for the cultivation of S. hygroscopicus CH-7 in the antibiot- ics production. Hexaen largest concentration was achived in the medium with waste glycerol from the biodiesel production from sunflower oil (38,7 µg/cm3), more than twice of the amount given to the glucose medium (19,3 µg/cm3). S. hygroscopicus CH-7 produces most azalomycine on the glucose medium, about 25% less on the pure glycerol and much less on the media with crude glycerol.
Species of the genus Streptomyces produce antibiotics and grow on sub- strates with a different carbon and nitrogen source. The increase of the yield of antibiotics can be achieved at an early stage ...of the investigation by changing the conditions of fermentation and the composition of the culture medium. During the production process of biodiesel by transesterification of plant oil, except for the target product the raw glycerol in relatively large amounts (10% of the input quantities of oil) is obtained. Glycerol generated in the alkali-cat- alyzed transesterification reaction can be regarded as crude fraction because besides glycerol, there are also traces of soap and dirt from the oil and catalyst residues. The possibility of the production of antibiotics by growing the cultures Streptomyces hygroscopicus CH-7 on the medium containing glycerol as the carbon source was studied in this work. The antibiotics production with crude glycerol remaining from the biodiesel production process from sunflower oil and rape seed oil was monitored under laboratory conditions. The yield of the produced antibiotics hexaene (H-85) and azalomycine and the glycerol con- centration change were followed during the fermentation. The waste glycerol from the biodiesel production from rapeseed oil proved to be the least suit- able carbon source for the cultivation of S. hygroscopicus CH-7 in the antibiot- ics production. Hexaen largest concentration was achived in the medium with waste glycerol from the biodiesel production from sunflower oil (38,7 µg/cm3), more than twice of the amount given to the glucose medium (19,3 µg/cm3). S. hygroscopicus CH-7 produces most azalomycine on the glucose medium, about 25% less on the pure glycerol and much less on the media with crude glycerol.
PRIKAZI Ćirić, Jovan
Социолошки преглед,
1974, Letnik:
8, Številka:
2-3
Book Review
Recenzirano
Odprti dostop
Review of:
JOVAN V. ĆIRIĆ - ANRI LEFEVR: URBANA REVOLUCIJA (HENRI LEFEBVRRE: LA
REVOLUTION URBAINE), Nolit, Beograd, 1974, str. 1—211. U prevodu: M. Vukmanović Mihajlović
The village of Dobri Dol is located in the South-Eastern Serbia. In 1948 the number of population in the village accounted for 1,222 while in 1978 -this number dropped to 504. As is seen this village ...too, like a lot of others in Serbia, has been affected 'by de-population process. The analysis aim at revealing not anly the sort of social and ethnological processes having been developing in the village of Dobri Dol but also the other processing developing in the presint-day Yugoslav village in general, taking, of course, the concrete investigation carried out in this village as the example.
•Syntheses of nanocomposites have been carried out in water/toluene biphasic system.•The emeraldine salt form and phenazine units were identified.•Au/PANI nanocomposites show higher conductivity than ...pure PANI.
Composites consisting of polyaniline (PANI) and gold nanoparticles (AuNPs) with an average size of 17 and 30nm were synthesized by an interfacial method performed in an immiscible water/toluene biphasic system. The effect of embedded AuNPs on the morphology, structure and physicochemical properties of Au/PANI nanocomposites was investigated using scanning and transmission electron microscopies, UV–vis, FTIR, Raman and ICP-AES spectroscopies, X-ray diffraction, elemental analysis and conductivity measurements. Microscopy studies indicated nanofibrous morphology for pure PANI and Au/PANI nanocomposites, while FTIR and Raman spectroscopies were confirmed emeraldine salt form of PANI chains and the presence of phenazine units. Also, Raman spectroscopy measurements revealed an inherent structural inhomogeneity at the macromolecular level that exist in PANI chains in its pure form as well as in Au/PANI nanocomposites. In addition, the increase of the electrical conductivity observed in the nanocomposites was discussed.
Self-assembled polyaniline (PANI) nanotubes, accompanied with nanoribbons, were synthesized by the oxidative polymerization of aniline with ammonium peroxydisulfate in an aqueous medium, in the ...presence of colloidal titanium dioxide (TiO
2) nanoparticles of 4.5
nm size, without added acid. The morphology, structure, and physicochemical properties of the PANI/TiO
2 nanocomposites, prepared at various initial aniline/TiO
2 mole ratios, were studied by scanning (SEM) and transmission (TEM) electron microscopies, FTIR, Raman and inductively coupled plasma optical emission (ICP-OES) spectroscopies, elemental analysis, X-ray powder diffraction (XRPD), conductivity measurements, and thermogravimetric analysis (TGA). The electrical conductivity of PANI/TiO
2 nanocomposites increases in the range 3.8
×
10
−4 to 1.1
×
10
−3
S
cm
−1 by increasing aniline/TiO
2 mole ratio from 1 to 10. The morphology of PANI/TiO
2 nanocomposites significantly depends on the initial aniline/TiO
2 mole ratio. In the morphology of the nanocomposite synthesized using aniline/TiO
2 mole ratio 10, nanotubes accompanied with nanosheets prevail. The nanocomposite synthesized at aniline/TiO
2 mole ratio 5 consists of the network of nanotubes (an outer diameter 30–40
nm, an inner diameter 4–7
nm) and nanorods (diameter 50–90
nm), accompanied with nanoribbons (a thickness, width, and length in the range of 50–70
nm, 160–350
nm, and ∼1–3
μm, respectively). The PANI/TiO
2 nanocomposite synthesized at aniline/TiO
2 mole ratio 2 contains polyhedral submicrometre particles accompanied with nanotubes, while the nanocomposite prepared at aniline/TiO
2 mole ratio 1 consists of agglomerated nanofibers, submicrometre and nanoparticles. The presence of emeraldine salt form of PANI, linear and branched PANI chains, and phenazine units in PANI/TiO
2 nanocomposites was proved by FTIR and Raman spectroscopies. The improved thermal stability of PANI matrix in all PANI/TiO
2 nanocomposites was observed.
We report on the possibility to build hierarchically organized three-dimensional (3D) titania spherical particles having high surface-to-volume-ratio, by aerosol processing of nanotubular building ...blocks. Morphology and crystal structure of titania based spherical assemblies, obtained in the temperature range from 150 to 650°C, were characterized by means of scanning and transmission electron microscopy, x-ray powder diffraction and Raman spectroscopy. Initial shape of 1D building units, nanotubes, was well preserved in the spherical assemblies processed at 150 and 450°C. Processing at 650°C resulted in a collapse of the nanotubular building blocks and formation of the assemblies of irregularly shaped TiO2 nanoparticles. Structural analysis revealed several phase transitions in titania spherical assemblies in course with the temperature increase indicating possibility of in-situ phase composition adjustment during aerosol processing.
