• Energy Research

Samples of sunflower Waste Cooking Oils (WCOs) subjected to several cycles of frying were treated with water under four different combinations of temperature and pH. The variation of the chemical composition of the oil samples was monitored through headspace Solid-Phase Microextraction (HS-SPME) coupled with gas-chromatographic technique (GC), 1H NMR spectroscopy and ESI+ mass spectrometry measurements. The possibility to modify the chemical composition of the recycled vegetable oil by tuning the water treatment parameters was exploited for the designing of a mini-plant for the production of bio-lubricants. A full description of the proposed prototype is also reported.

Salinity caused by NaCl is an abiotic stress inducing morphological and metabolic disorders. The impact of salinity (0, 65 and 130 mM NaCl) on morphological traits, elemental and volatiles composition of six rocket genotypes (G1-G6) was explored. A significant reduction of shoot biomass, plant height and leaf area as function of genotype and salinity level was observed. G5 was highly affected by NaCl: at 65 and 130 mM plants were 48.6% and 59.1% shortened compared with to control. The volatiles compositions was also analyzed. Glucosinolates increased under 65 mM, then decreased at 130 mM. In G1, glucosinolates start with 7.4 (control), raised to 21.50 (65 mM) and finally dropped to 4.34 (130 mM). This trend was observed also for erucin, the major rocket's isothiocyanate. Rockets could be irrigated with saline water improving the health promoting compounds production. The evaluation of different genotype seems to be of great interest for future breeding programs.

Wheat straw is an abundant source of lignocellulosic biomass that is generally not utilized for biofuel production, nor for other uses. Recent EU renewable energy directive fosters bioethanol production through lignocellulosic sugars fermentation, but the cost of this process is an issue that often depends on biomass characteristics. Lignin is a class of three-dimensional polymers providing structural integrity of plant tissues. Its complex structure, together with hemicelluloses and uronic acids content, could affect the ability of hydrolyzing biomass to fermentable sugars. To get insights into this variation, a set of 10 durum wheat genotypes was analyzed to determine variation of straw digestibility to fermentable sugars. The results showed that the lignin content was the major factor determining the recalcitrance to enzymatic process. The analysis of Spearman’s correlation indicated that the sugar released after enzymatic hydrolysis had a negative connection with the lignin content, while it was positively correlated with the culm length. The possible role of other cell wall components, such as arabinose and uronic acids, was also discussed. This work aimed at analyzing the diversity of lignocellulosic digestibility to fermentable sugars of wheat straw in a small germplasm collection. Some of the selected genotypes were characterized by high sugars digestibility and high grain yield, characteristics that could make biorefining of wheat straw profitable.

A relevant improvement of the cultivar conditions of Rosmarinus officinalis L. in desert areas was achieved by a specific combination between an irrigation system and soil conditioner. A drastic reduction in water employment was obtained without affecting the quality of the plants, which was determined by monitoring the growth parameters and essential oil characteristics. In particular, the effect of surface and subsurface drip irrigation systems and different soil conditioners on the growth parameters, yield, and essential oil constituents of rosemary plants was assessed. Field experiments at the Agricultural Research Station (Al-Adlya farm), SEKEM Group Company, El-Sharkiya Governorate, Egypt, conducted over the two seasons, revealed the effectiveness of subsurface irrigation systems in obtaining better performances, especially in terms of saving water. The combination of subsurface irrigation and the conditioner HUNDZ soil with bentonite showed the maximum mean values of growth characteristics compared with other soil amendments during both seasons. The possibility to employ a water-saving irrigation system at the subsurface level without any drawback in the resulting plants was also explored in terms of molecular composition. Gas chromatography-mass (GC-MS) analysis of the essential oils extracted from plants grown under different irrigation conditions revealed a comparable composition in both cases. The quality of the system that showed the best performance was also confirmed by the comparable yield of the essential oil.

The chemical composition and the color of samples of waste cooking oils (WCOs) were determined prior to and after filtration on two different pads of bentonite differing in particle size. The volatile fraction was monitored by headspace solid-phase microextraction (HS-SPME) coupled with gas-chromatography, while the variation of the composition of the main components was analyzed by 1H NMR. Both techniques allowed the detection of some decomposition products, such as polymers, terpenes, and derivatives of the Maillard process. The analysis of the chemical composition prior to and after bentonite treatment revealed a tendency for the clays to retain specific chemical groups (such as carboxylic acids or double bonds), independent of their particle size. A pair comparison test was conducted in order to detect the sensory differences of the intensity of aroma between the WCO treated with the two different bentonites. In addition, characterization of the bentonite by means of powder X-ray diffraction (XRD) and thermogravimetric measurements (TG) was performed.

Recycling of waste cooking oil represents a source of convenient raw materials for industry. Within the large number of products derived from the treatment of waste cooking oil, eco-friendly lubricants grown in importance during the last years. Recycling process for such application consists usually of acid or basic degumming followed by a filtration step. The effect of the specific type of acid degumming on the density and on the flash point of the recycled oil was evaluated employing full factorial design. Two mathematical equations were derived which allow to estimate respectively the density and the flash point of the recycled oil, depending on the: (a) pH of the washing solution, (b) oil/water ratio, (c) temperature of the system, and (d) the stirring time.