The deposition of mesoporous silica (SiO(2)) on carbon nanotubes (CNTs) has opened up a wide range of assembling possibilities by exploiting the sidewall of CNTs and organosilane chemistry. The resulting systems may be suitable for applications in catalysis, energy conversion, environmental chemistry, and nanomedicine. However, to promote the condensation of silicon monomers on the nanotube without producing segregated particles, (OR)(4-x)SiO(x)(x-) units must undergo nucleophilic substitution by groups localized on the CNT sidewall during the transesterification reaction. In order to achieve this preferential attachment, we have deposited silica on oxidized carbon nanotubes (single-walled and multiwalled) in a sol-gel process that also involved the use of a soft template (cetyltrimethylammonium bromide, CTAB). In contrast to the simple approach normally used to describe the attachment of inorganic compounds on CNTs, SiO(2) nucleation on the tube is a result of nucleophilic attack mainly by hydroxyl radicals, localized in a very complex surface chemical environment, where various oxygenated groups are covalently bonded to the sidewall and carboxylated carbonaceous fragments (CCFs) are adsorbed on the tubes. Si-O-C covalent bond formation in the SiO(2)-CNT hybrids was observed even after removal of the CCFs with sodium hydroxide. By adding CTAB, and increasing the temperature, time, and initial amount of the catalyst (NH(4)OH) in the synthesis, the SiO(2) coating morphology could be changed from one of nanoparticles to mesoporous shells. Concomitantly, pore ordering was achieved by increasing the amount of CTAB. Furthermore, preferential attachment on the sidewall results mostly in CNTs with uncapped ends, having sites (carboxylic acids) that can be used for further localized reactions.

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Raw glycerol is a byproduct of biodiesel production that currently has low to negative value for biodiesel producers. One option for increasing the value of raw glycerol is to use it as a feedstock for microbial production. Bacillus subtilis LSFM 05 was used for the production of fengycin in a mineral medium containing raw glycerol as the sole carbon source. Fengycin was isolated by acid precipitation at pH 2 and purified by silica gel column chromatography and characterized using electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) with collision-induced dissociation (CID). The mass spectrum revealed the presence of the ions of m/z 1,435.7, 1,449.9, 1,463.8, 1,477.8, 1,491.8 and 1,505.8, which were further fragmented by ESI-MS/MS. The CID profile showed the presence of a series of ions (m/z 1,080 and 966) and (m/z 1,108 and 994) that represented the different fengycin homologues A and B, respectively. Fengycin homologues A and B are variants that differ at position 6 of the peptide moiety, having either Ala or Val residues, respectively. Mass spectrometry analyses identified four fengycin A and three fengycin B variants with fatty acid components containing 14-17 carbons. These results demonstrate that raw glycerol can be used as feedstock to produce fengycin, and additional work should focus on the optimization of process conditions to increase productivity.

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