Impact of an Engineered Copper-Titanium Dioxide Nanocomposite and Parent Substrates on the Bacteria Viability,Antioxidant Enzymes and Fatty Acid Profiling

Due to the systematic increase in the production of nanomaterials (NMs) and their applications in many areas of life, issues associated with their toxicity are inevitable. In particular, the performance of heterogeneous NMs, such as nanocomposites (NCs), is unpredictable as they may inherit the properties of their individual components. Therefore, the purpose of this work was to assess the biological activity of newly synthesized Cu/TiO₂-NC and the parent nanoparticle substrates Cu-NPs and TiO₂-NPs on the bacterial viability, antioxidant potential and fatty acid composition of the reference Escherichia coli and Bacillus subtilis strains. Based on the toxicological parameters, it was found that B. subtilis was more sensitive to NMs than E. coli. Furthermore, Cu/TiO₂-NC and Cu-NPs had an opposite effect on both strains, while TiO₂-NPs had a comparable mode of action. Simultaneously, the tested strains exhibited varied responses of the antioxidant enzymes after exposure to the NMs, with Cu-NPs having the strongest impact on their activity. The most considerable alternations in the fatty acid profiles were found after the bacteria were exposed to Cu/TiO₂-NC and Cu-NPs. Microscopic images indicated distinct interactions of the NMs with the bacterial outer layers, especially in regard to B. subtilis. Cu/TiO₂-NC generally proved to have less distinctive antimicrobial properties on B. subtilis than E. coli compared to its parent components. Presumably, the biocidal effects of the tested NMs can be attributed to the induction of oxidative stress, the release of metal ions and specific electrochemical interactions with the bacterial cells.     

Kinetics of biofuel generation from deodorizer distillates derived from the physical refining of olive oil and squalene recovery

The recovery of squalene from deodorizer distillate derived from the physical refining of olive oil was evaluated by combining pressurized acidic esterification in a closed system with vacuum distillation. Esterification was carried out at 341, 359, 366, 391 and 395 K. The reaction at 395 K was found to be satisfactory as it decreased the acid value by 99.21% and generated a FAME concentration of 67.53% within 1 h. In order to demonstrate that the generation of FAME from deodorizer distillate was mainly due to the transformation of FFA, the reaction extent, which characterizes the reaction and simplifies calculations, was evaluated for FFA removal and the generation of FAME. Subsequent vacuum distillation allowed the separation of one fraction rich in FAME (94%), which can be used as a biofuel and accounted for 85% of the initial mass, and another fraction that was rich in squalene (78%) and may be used for manufacturing pharmaceutical products. The global squalene yield was 117 g kg⁻¹ initial deodorizer distillate.     

Well-to-Tank environmental analysis of a renewable diesel fuel from vegetable oil through co-processing in a hydrotreatment unit

A Life Cycle Assessment (LCA) study of HidroBioDiésel (HBD) was carried out. This partly renewable diesel fuel is obtained from the co-processing of soybean vegetable oil with conventional fossil fuel in hydrotreating facilities of crude oil refineries. The environmental profile of HBD was assessed for the fossil energy use and climate change impact categories. The production systems of equivalent fuels -blends of Fatty Acid Methyl Ester (FAME, a biofuel obtained by means of transesterification of vegetable oil) and mineral diesel with sulphur content below 10 ppm were also assessed for comparison purposes. The environmental performance of HBD systems compares favourably to those of FAME and diesel blends for the selected impact categories. The estimated environmental benefits of HBD (assuming a 13% renewable blend) include reductions of up to 2% in fossil energy use and 9% in climate change impacts.     

Sequestration of CO2 using microorganisms and evaluation of their potential to synthesize biomolecules

ABSTRACT

Microalgae are the unicellular or multicellular photosynthetic microorganisms that can efficiently fix carbon dioxide (CO₂) from various sources such as the environment, industrial flue gas, and some carbonate salts. In the present study, one green microalgal strain and a cyanobacterial consortium were used separately for the sequestration of CO₂ at different pHs (7–11), at different initial concentrations of CO₂ (5–20%), and at various inoculum sizes (5–12.5%). The maximum sequestration of CO₂ was found to be 74.37 ± 0.49% and 71.12 ± 0.05% at 5% and 15% CO₂ for green algae and cyanobacterial consortium. The biomass generated after sequestration of CO₂ was utilized for the synthesis of biomolecules.     

Analysis of the Content of Fatty Acid Methyl Esters in Biodiesel by Fourier-Transform Infrared Spectroscopy: Method and Comparison with Gas Chromatography

The increasing importance of sustainability in energy production has led to a global commitment to the use of fuels derived from renewable biological sources, such as biodiesel produced from plant crops or biomass residues, that do not compete with human food for their production. For a biofuel to be considered biodiesel, it must satisfy the specifications described in the UNE 14214, with the UNE-EN 14103 referring to the determination of fatty acid methyl ester content. This standard applies gas chromatography as an analytical technique. Gas chromatography is a widely used technique in the analysis of methyl ester although it has a number of drawbacks such as: long analysis times, a high consumption of high-quality gases and internal standards, does not allow the analysis of different compounds with the same column, etc. From an industrial production point of view, is necessary to know the fatty acid methyl ester content in biodiesel samples quickly. This paper studies the development of an analytical method using Fourier transform infrared spectroscopy (FTIR) as alternative to gas chromatography (GC), since it is a simple, rapid, and precise analytical technique to quantify fatty acid methyl ester content in biofuel samples.     

Spectroscopic sensor techniques applicable to real-time biodiesel determination

The term biodiesel refers to the Fatty Acid Alkyl Esters (FAAE) derived from vegetable, animal or waste oil feedstocks. This alternative fuel is increasingly becoming a significant part of the transport sector with over 10 million tonnes sold in the EU in 2007. Currently a small amount of biodiesel (presently 3.5% in the UK) is present in diesel fuel but this could rise to up to 30% in the medium term. As biodiesel is not one chemical compound but an amalgamation of different FAAE, the physical properties of the diesel fuel are not only dependent on the amount of biodiesel in the diesel fuel (blend level) but also on the fatty acid profile of the biodiesel. In this paper we report on an initial study to assess a range of current techniques which could be used in the future as a basis to determine blend level in unknown samples of diesel and gain further information on the fatty acid profile of the biodiesel in the blend. The three techniques applied were FT-IR spectroscopy, refractive index and UV-Vis spectroscopy.     

Investigation of terminalia (Terminalia belerica Robx.) seed oil as prospective biodiesel source for North-East India

Terminalia (Terminalia belerica Robx.) is available in the northeastern region of India. The fruit of terminalia has some medicinal value and its kernel contains 43% oil. The prospect of terminalia oil for biodiesel production is investigated with reference to some relevant properties. The fatty acid profile of oil extracted from terminalia is found comparable with similar seed oils attempted for biodiesel production in this region. Terminalia oil contains 32.8% palmitic acid, 31.3% oleic acid, and 28.8% linoleic acid. The calorific value and kinematic viscosity of terminalia oil are 37.50 MJ/kg and 25.60 cSt, respectively. The calorific value and cetane number of terminalia FAME are within the acceptable limit of the EN 14214 standard. However, the flash point of terminalia FAME (90 °C) is relatively lower than the minimum required standard. Overall, the properties of biodiesel obtained from terminalia seed conform to the existing biodiesel standard. In addition to assisting the national biodiesel mission, the extension and regeneration of forest areas through terminalia planting would help us to curb the seemingly irreversible trend of de-forestation in the northeast region of India.     

Thermally assisted in-line methylation and gas chromatography with statistical data analysis for determination of fatty acid distribution and fingerprinting of plant seeds and oils

Received: 11 October 1999 / Revised version: 7 December 1999