Home About us Contact
|
Home About us Contact | ||
|
|
||
Oil Available (oil + available)
Selected AbstractsBiodesulfurization of dibenzothiophene using recombinant Pseudomonas strainJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2008Lavanya Meesala Abstract BACKGROUND: The sulfur content in crude oil available from various sources ranges from 0.03 to values as high as 8.0 wt%. These high quantities of sulfur must be removed before the crude oil is processed because combustion of this oil would result in severe environmental pollution, such as acid rain. Due to high utility and operating costs, the conventional hydrodesulfurization process (HDS) is considered to be uneconomic. The biotechnological option, biodesulfurization (BDS) seems an attractive low cost, environmentally benign technology. RESULTS: This paper reports the development of a recombinant strain of bacteria designed by introducing desulfurizing, dsz genes containing plasmid pSAD 225-32, which was isolated from Rhodococcus erythropolis IGTS8 into a gram negative solvent-tolerant bacterium, Pseudomonas putida (MTCC 1194). This recombinant bacterium can desulfurize the dibenzothiophene (DBT) in the sulfur selective 4S-pathway. It has been observed that for the same concentration of DBT, the recombinant strain's growth rate is greater than that of the parent strain. Increasing the concentration of DBT resulted in an increase of lag phase as well as decreased growth rate, which shows that the bacteria is following substrate inhibition type kinetics. This genetically modified bacterium can desulfurize 73.1% of 1.2 mmol L,1 DBT (dissolved in ethanol) in 67 h of cultivation time using growing cells. CONCLUSIONS: It is concluded that further research in this area of biodesulfurization using genetically modified organisms may remove the bottlenecks presently in the way of commercialization of the BDS process. Copyright © 2007 Society of Chemical Industry [source] Dietary effects on growth, plasma lipid and tissues of rats fed with non-conventional oil of Telfairia occidentalisJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 13 2004Ibironke A Ajayi Abstract The nutritional value of Telfairia occidentalis seed and seed oil available in local market was studied in rats. The average values of the proximate analysis on dry matter basis were 203 g kg,1 crude protein, 536.3 g kg,1 fat, 39 g kg,1 ash, 95 g kg,1 crude fibre and 43.7 g kg,1 carbohydrate, while the moisture content was 75 g kg,1. The mineral analyses showed that T occidentalis seeds contain potassium (3280 mg kg,1), sodium (1230 mg kg,1), magnesium (60.8 mg kg,1), calcium (60.8 mg kg,1) and iron (13.0 mg kg,1). The oil extracted from the seed sample showed physicochemical properties that suggest its suitability for edible and industrial uses. The oil contained high levels of unsaturated fatty acids, oleic and linoleic, which accounted for 63.22% of total fatty acids recovered, while palmitic acid (27.4% of the oil by weight) was the most prevalent saturated fatty acid in the oil. No trace of eleostearic acid was detected in the oil. The effect on physical appearance, weight gain, organ weight, tissue and plasma cholesterol and triacylglycerol levels was determined in rats fed a diet containing 5% T occidentalis oil. These were compared with those of rats fed a control diet (0% T occidentalis oil) over an 8 week study period. Weekly monitoring of the rats showed good physical appearance and steady weight increase. The test rats were not anaemic and no mortality was recorded. While there was a significantly higher (p < 0.05) level of cholesterol in the heart of test rats compared with the control, there was a significantly lower (p < 0.05) plasma cholesterol level, suggesting that T occidentalis seed oil can be used to lower plasma levels of cholesterol. Histological examination of the sections of the heart, liver, kidney and spleen of the test rats revealed varying degrees of pathology. These include artherosclerotic changes in the walls of vasa vasori and lymphatics in the heart and hyaline degeneration of myofibrils, fatty infiltration of hepatocytes, and glomerular and tubular degeneration in the kidneys. These lesions may have been due to the effect of fatty acids, especially erucic acid, in the seed oil, which at 1.24% (less that the 5% conventional allowable limit for edible oils) may be intolerable for rats and may be unsuitable for human consumption. The seed oil may be used for industrial purposes such as soap making, lubrication and cosmetics for which it is well suited. Copyright © 2004 Society of Chemical Industry [source] Forecasting volatility for options valuationOPEC ENERGY REVIEW, Issue 3 2006Mahdjouba Belaifa The petroleum sector plays a neuralgic role in the basement of world economies, and market actors (producers, intermediates, as well as consumers) are continuously subjected to the dynamics of unstable oil market. Huge amounts are being invested along the production chain to make one barrel of crude oil available to the end user. Adding to that are the effect of geopolitical dynamics as well as geological risks as expressed in terms of low chances of successful discoveries. In addition, fiscal regimes and regulations, technology and environmental concerns are also among some of the major factors that contribute to the substantial risk in the oil industry and render the market structure vulnerable to crises. The management of these vulnerabilities require modern tools to reduce risk to a certain level, which unfortunately is a non-zero value. The aim of this paper is, therefore, to provide a modern technique to capture the oil price stochastic volatility that can be implemented to value the exposure of an investor, a company, a corporate or a Government. The paper first analyses the regional dependence on oil prices, through a historical perspective and then looks at the evolution of pricing environment since the large price jumps of the 1970s. The main causes of oil prices volatility are treated in the third part of the paper. The rest of the article deals with volatility models and forecasts used in risk management, with an implication for pricing derivatives. [source] Phytochemical and antioedematogenic studies of commercial copaiba oils available in BrazilPHYTOTHERAPY RESEARCH, Issue 6 2001Valdir F. Veiga Jr Abstract The composition of eight samples of commercial copaiba oils, used in the Amazonian region as antiinflammatory agents and available in popular markets, were analysed by gas chromatography/mass spectrometry (HRGC-MS). Major differences were observed in their chemical composition and some adulterations were pointed out. When tested in vivo oils 1 and 3, and to a lesser extent oil 6, significantly inhibited bradykinin-induced oedema formation. The other tested oils had no effect. When assessed in carrageenan-induced oedema formation, oils 1, 2 and 6, but not oil 3, significantly attenuated the oedema formation. The other tested oils failed to affect carrageenan-induced paw oedema. Oils 1 and 6 were further fractionated and several sesquiterpenes and diterpenes were detected. It is suggested that the naturally occurring sesquiterpenes present in the copaiba oils seem to be responsible for the antiinflammatory action reported in the folk medicine. Furthermore, our results clearly show an adulteration in copaiba oils available in Brazil. Copyright © 2001 John Wiley & Sons, Ltd. [source] Impact of topical oils on the skin barrier: possible implications for neonatal health in developing countriesACTA PAEDIATRICA, Issue 5 2002GL Darmstadt Topical therapy to enhance skin barrier function may be a simple, low-cost, effective strategy to improve outcome of preterm infants with a developmentally compromised epidermal barrier, as lipid constituents of topical products may act as a mechanical barrier and augment synthesis of barrier lipids. Natural oils are applied topically as part of a traditional oil massage to neonates in many developing countries. We sought to identify inexpensive, safe, vegetable oils available in developing countries that improved epidermal barrier function. The impact of oils on mouse epidermal barrier function (rate of transepidermal water loss over time following acute barrier disruption by tape-stripping) and ultrastructure was determined. A single application of sunflower seed oil significantly accelerated skin barrier recovery within 1 h; the effect was sustained 5 h after application. In contrast, the other vegetable oils tested (mustard, olive and soybean oils) all significantly delayed recovery of barrier function compared with control- or Aquaphor-treated skin. Twice-daily applications of mustard oil for 7 d resulted in sustained delay of barrier recovery. Moreover, adverse ultrastructural changes were seen under transmission electron microscopy in keratin intermediate filament, mitochondrial, nuclear, and nuclear envelope structure following a single application of mustard oil. Conclusion: Our data suggest that topical application of linoleate-enriched oil such as sunflower seed oil might enhance skin barrier function and improve outcome in neonates with compromised barrier function. Mustard oil, used routinely in newborn care throughout South Asia, has toxic effects on the epidermal barrier that warrant further investigation. [source] | |||||||||||||