C10 C16 Research Articles

Differential biodegradation of alkanes in crude oil by three oleophilic strains

Ex situ bioremediation of crude oil in bioreactors by oleophilic bacteria permits to regulate temperature, nutrients and oxygen and the results in petroleum removal are much more effective than in situ bioremediation. This article quantify the biodegradation of alkanes which conform crude oil in bioreactors by three oleophilic strains. Samples were collected from the bioreactors and extracted in dichloromethane (10:1 aqueous/organic v/v) for amplification in GC-FID analysis of individual alkanes. 94% of crude oil (initial concentration 8.6 g l−1) is removed in 24 days by Bacillus licheniformis and in 38 days by Pseudomonas putida and Paenibacillus glucanolyticus. Higher biodegradation rates (9.0–26.5 mg l−1d−1) are reached for the lightest fraction of crude oil by Bacillus licheniformis (C10–C16), and much lower for C22–C25 alkanes (4.4–8.9 mg l−1d−1). Pseudomonas putida and Paenibacillus glucanolyticus degrade a wide range of alkanes at 1.6–9.6 mg l−1d−1, with preference over C8–C16 hydrocarbons. Heptane and octane (alkanes cited to be toxic) are difficult for biodegradation in two strains (B. licheniformis and P. putida) and a recalcitrant “window” C18–C21 is observed for the three oleophilic strains in the alkane range studied.

Reclamation of Hydrocarbon Contaminated Soils Using Soil Amendments and Native Plant Species

Petroleum hydrocarbons are among the top contaminants of the natural environment with serious concern worldwide due to their effects on soil, water, and surroundings. A two-year field experiment was implemented to evaluate reclamation of hydrocarbon contaminated (diesel fuel, crude oil) soils in central Alberta Canada using amendments (20% city waste compost, ammonium sulphate inorganic fertilizer) and seeding with a native grass mix. Soils amended with compost or compost-fertilizer had the greatest vegetation cover and biomass and lowest hydrocarbon concentrations at the end of the study. Fertilizer treatments had less vegetation cover and higher hydrocarbon concentrations, which were similar to the no amendment treatment. Seeding with native grasses had no effect on hydrocarbon degradation or total canopy cover, although vegetation composition showed some effect. Seeding increased cover of perennial native grasses in all amendment treatments, with greatest cover in compost and compost-fertilizer amended soils. Within two years after reclamation concentrations of F2 (carbon length > C10–C16) and F4 (>C34–C60) hydrocarbons in crude oil contaminated soils were below Canadian guidelines. Overall, compost was an effective amendment for reclamation of diesel fuel and crude oil contaminated soils and seeding was beneficial for reducing cover of non-native forbs. Fertilizer addition to compost may not enhance revegetation and remediation of hydrocarbon contaminated soils.

Evaluating the Impact of Nutrient Doses on Biostimulation of Petroleum Hydrocarbon Biodegradation in Cold Region Soils

Biostimulation by addition of nitrogen (N) and phosphorus (P) for enhancement of biodegradation of petroleum hydrocarbons in contaminated soils is a common practice in sub-Arctic (cold) regions. Based on the data reported in 58 peer-reviewed papers on hydrocarbon degradation in northern region soils, there was no identifiable optimal nutrient dose, although applied doses ranged over 3 orders of magnitude. Microcosm slurry biodegradation experiments conducted over a range of N (41 to 1350 mg/kg) and P (46 and 115 mg/kg) doses, using a northern site soil spiked with Arctic diesel, also showed comparable results. While addition of nutrients improved degradation extents, the degradation extents were not dependent on N and P doses. Biodegradation rate constants for C10–C16 and C16–C24 hydrocarbon fractions, however, showed the highest enhancements for the lowest N dose. Microbial community composition analysis based on 16S rRNA sequencing of DNA extracted from microcosms amended with only diesel, only nutrients, and both diesel and nutrients revealed that diesel enriched hydrocarbon degraders such as Pseudomonadaceae and Burkholderiaceae. Overall, our results and analyses show limited benefits of biostimulation of hydrocarbon degradation with high nutrient doses, and low nutrient doses are generally more or equally effective.

Hydrocracking of Octacosane and Cobalt Fischer–Tropsch Wax over Nonsulfided NiMo and Pt-Based Catalysts

The effect of activation environment (N2, H2 and H2S/H2) on the hydrocracking performance of a NiMo/Al catalyst was studied at 380 °C and 3.5 MPa using octacosane (C28). The catalyst physical structure and acidity were characterized by BET, XRD, SEM-EDX and FTIR techniques. The N2 activation generated more active nonsulfided NiMo/Al catalyst relative to the H2 or H2S activation (XC28, 70–80% versus 6–10%). For a comparison, a NiMo/Si-Al catalyst was also tested after normal H2 activation and showed higher activity at the same process conditions (XC28, 81–99%). The high activity of the NiMo/Al (N2 activation) and NiMo/Si-Al catalysts was mainly ascribed to a higher number of Brønsted acid sites (BAS) on the catalysts. The hydrocracking of cobalt wax using Pt/Si-Al and Pt/Al catalysts confirmed the superior activity of the Si-Al support. A double-peak product distribution occurred at C4–C6 and C10–C16 on all catalysts, which illustrates secondary hydrocracking and faster hydrocracking at the middle of the chain. The nonsulfided NiMo/Al and Pt/Al catalysts, and NiMo/Si-Al catalyst produced predominantly diesel (sel. 50–70%) and gasoline range (sel. > 50%) hydrocarbons, respectively, accompanied by some CH4 and light hydrocarbons C2–C4. On the other hand, the hydrocarbon distribution of the Pt/Si-Al varied with conditions (i.e., diesel sel. 87–90% below 290 °C or gasoline sel. 60–70% above 290 °C accompanied by little CH4) The dependence of the isomer/paraffin ratio on chain length was studied as well. The peak iso/paraffin value was observed at C10–C13 for the SiAl catalyst.

Electrokinetic remediation of petroleum hydrocarbon contaminated soil (I)

The remediation of petroleum hydrocarbons (TPH) in a contaminated soil by electrokinetic (EK) treatment was studied in the laboratory. The effects of applying a constant electrical current on soil pH, moisture content, electrical conductivity (EC), temperature, and the concentrations of three fractions of TPH (C10–C16, C17–C34 and C35–C40) were investigated. The experiment was run for seven days and soil samples were collected at the end of the 7 day period for analysis of soil pH and TPH concentration. There were extreme pH conditions near the electrodes. At the end of the experiment there was around a 37% reduction of C10–C16 chain compounds compared to the initial concentration of 164 ± 18 mg/kg. The study investigated TPH remediation to a depth of 24 cm, which is significantly more than most studies of EK remediation of TPH-contaminated soils. We observed reductions in TPH concentrations even at a depth of 24 cm. The spatial distribution of reductions in TPH concentrations was also studied and it was observed that more remediation occurred near the cathodes than near the anodes. Further, the greatest reductions in TPH concentrations were recorded near the electrodes in the lowest and middle parts of the experimental set-up. The application of electrokinetics to remediate TPH-contaminatedsoils could be a viable option as an in situ remediation technology.

Formation kinetics of hydrocarbon compounds in the vacuum gas oil oxycracking process

The kinetics of the formation of oxygen-free hydrocarbon compounds obtained during the process of oxidation of vacuum gas oil at 450–550 °C for 2700 s of conducting of the process was studied. It was established that the highest rate of hydrocarbon formation was noted for the C1–C4 fraction starting from the moment the process started and up to 900 s (1.76 × 10−8 – 4.58 × 10−8). For other fractions, reaction rate maximums were noted: for C5–C9—300 s from the start of the process; for C10–C12—in the interval between 300 and 900 s, i.e. at 600 s process duration; for the raw fractions C22–C30, C31–C35 and C36–C40, grew after 1800s. The data on the influence of the process temperature on the rate of hydrocarbon formation allowed us to establish that the oxycracking process is limited by the formation of C10–C16 hydrocarbon fractions. The increase in contact time to a greater extent affects the rate of formation of hydrocarbons C1–C4 and C17–C21. The features of the rate of hydrocarbon production as a function of the amount of oxygen were found out: the rate of formation of hydrocarbons C1–C4 and C17–C21 increases with increasing oxygen content (in the case of C17–C21 it passes through a minimum); C5–C9 and C13–C16—monotonously decreases; C10–C12 passes through a maximum at an oxidation state of 1%, which undoubtedly indicates the role of oxygen in the destructive processes of the formation of hydrocarbons that do not contain oxygen under oxycracking conditions.

CYP505E3: A Novel Self‐Sufficient ω‐7 In‐Chain Hydroxylase

AbstractThe self‐sufficient cytochrome P450 monooxygenase CYP505E3 from Aspergillus terreus catalyzes the regioselective in‐chain hydroxylation of alkanes, fatty alcohols, and fatty acids at the ω‐7 position. It is the first reported P450 to give regioselective in‐chain ω‐7 hydroxylation of C10–C16 n‐alkanes, thereby enabling the one step biocatalytic synthesis of rare alcohols such as 5‐dodecanol and 7‐tetradecanol. It shows more than 70 % regioselectivity for the eighth carbon from one methyl terminus, and displays remarkably high activity towards decane (TTN≈8000) and dodecane (TTN≈2000). CYP505E3 can be used to synthesize the high‐value flavour compound δ‐dodecalactone via two routes: 1) conversion of dodecanoic acid into 5‐hydroxydodecanoic acid (24 % regioselectivity), which at low pH lactonises to δ‐dodecalactone, and 2) conversion of 1‐dodecanol into 1,5‐dodecanediol (55 % regioselectivity), which can be converted into δ‐dodecalactone by horse liver alcohol dehydrogenase.

Antimicrobial and cytotoxic activity of (thio)alkyl hexopyranosides, nonionic glycolipid mimetics

A series of 19 synthetic alkyl and thioalkyl glycosides derived from d-mannose, d-glucose and d-galactose and having C10–C16 aglycone were investigated for cytotoxic activity against 7 human cancer and 2 non-tumor cell lines as well as for antimicrobial potential on 12 bacterial and yeast strains. The most potent compounds were found to be tetradecyl and hexadecyl β-d-galactopyranosides (18, 19), which showed the best cytotoxicity and therapeutic index against CCRF-CEM cancer cell line. Similar cytotoxic activity showed hexadecyl α-d-mannopyranoside (5) but it also inhibited non-tumor cell lines. Because these two galactosides (18, 19) were inactive against all tested bacteria and yeast strains, they could be a target-specific for eukaryotic cells. On the other hand, β-D-glucopyranosides with tetradecyl (11) and hexadecyl (12) aglycone inhibited only Gram-positive bacterial strain Enterococcus faecalis. The studied glycosides induce changes in the lipid bilayer thickness and lateral phase separation at high concentration, as derived from SAXS experiments on POPC model membranes. In general, glucosides and galactosides exhibit more specific properties. Those with longer aglycone show high cytotoxicity and therefore, they are more promising candidates for cancer cell line targeted inhibition.

Enzymatic synthesis and characterization of maltoheptaose-based sugar esters

In this study, maltoheptaose (G7)-based sugar esters were synthesized from maltoheptaose and fatty acids (C10–C16) using a commercial lipase. With the exception of dimethyl sulfoxide (DMSO; 76.4%, w/v), G7 showed only limited solubility in organic solvents. Among the fatty acids, palmitic acid (PA) was the best substrate for G7-based ester formation. G7-PA ester was successfully synthesized as the monoester structure exclusively in 10% DMSO of t-butanol with a 22% conversion yield. NMR and enzymatic analyses of the purified monoester product revealed that the ester bond in the G7 was located at C-6 of the glucose at the reducing end. The G7-PA monoester showed the melting temperature at 56.3 °C that was 6.5 °C lower than that of the free PA and exhibited a different endothermic pattern from the free G7. The G7-PA monoester exhibited excellent emulsifier potential with more even droplet size distribution compared with the commercial sucrose esters for an oil-in-water emulsion system.

Catalytic Deoxygenation of Hexadecyl Palmitate as a Model Compound of Euglena Oil in H2 and N2 Atmospheres

Hexadecyl palmitate (C15H31COOC16H33, used as a model compound for Euglena oil) was deoxygenated to hydrocarbons over various solid catalysts in autoclave reactors. In a H2 atmosphere, 1 wt.% of Pd/Mg(Al)O catalyst, derived from a hydrotalcite precursor, yielded a C15H31COOC16H33 conversion close to 100%, and a C10‒C16 (aviation fuel range) hydrocarbon yield of 90.2% for the deoxygenation of C15H31COOC16H33 at 300 °C for 2 h. In a N2 atmosphere, 1 wt.% of Pd/Mg(Al)O catalyst yielded a C10‒C16 hydrocarbon yield of 63.5%, which was much higher than those obtained with Mg(Al)O (15.1%), H-ZSM-5 (8.3%), and 1 wt.% Pd/C (26.2%) for the deoxygenation of C15H31COOC16H33 at 300 °C for 2 h. The Pd metal site and the solid base site in Mg(Al)O had a synergetic effect on the deoxygenation of C15H31COOC16H33 in N2 atmosphere over the Pd/Mg(Al)O catalyst. By prolonging the reaction time to 5 h for reaction at 300 °C in N2 atmosphere, the yield of C10‒C16 hydrocarbons increased to 80.4% with a C15H31COOC16H33 conversion of 99.1% over the 1 wt.% Pd/Mg(Al)O catalyst.

Effect of evaporative weathering and oil-sediment interaction on the fate and behavior of diluted bitumen in marine environments. Part 2. The water accommodated and particle-laden hydrocarbon species and toxicity of the aqueous phase

In this study, the water accommodated and particle-laden hydrocarbon species, and the toxicity of the aqueous phase after oil-sediment interactions by varying the weathering states of diluted bitumen (Cold Lake blend (CLB)), oil type from light to heavy, and sediment type. Compared to the original oils, the sediment-laden total petroleum hydrocarbons (TPH) contained fewer hydrocarbons in the carbon range <C10, comparable contents in C10–C16 range, higher contents in both the C16–C34 and >C34 range. Sediment-laden oil amounts generally decreased with an increased viscosity and asphaltene content of the test oils, as well as with increased sediment particle size. The presence of sediments significantly decreased the oil accommodated in water due to the formation of oil particulate aggregates (OPA) after mixing and settling. Less water accommodated TPH and polycyclic aromatic hydrocarbons (PAHs) were observed for weathered CLB products. However, oil and sediment types did not clearly affect the water accommodated TPH and PAHs. Light molecular PAHs and their alkylated congeners accounted for most of the water accommodated PAH congeners. A microtoxicity test demonstrated that with or without sediment, and regardless of sediment type, the toxicity of the water phase did not change significantly. Light oil of Alberta sweet mixed blend (ASMB) had the highest toxicity, followed by fresh CLB, and then all other oils, suggesting that ASMB and fresh CLB had relatively higher levels of light toxic components dissolved in the water phase compared with the other tested oils.

Enhanced bioremediation of nutrient-amended, petroleum hydrocarbon-contaminated soils over a cold-climate winter: The rate and extent of hydrocarbon biodegradation and microbial response in a pilot-scale biopile subjected to natural seasonal freeze-thaw temperatures

A pilot-scale biopile field experiment for nutrient-amended petroleum-contaminated fine-grained soils was performed over the winter at a cold-climate site. The rate and extent of hydrocarbon biodegradation and microbial responses were determined and corresponded to the on-site soil phase changes (from unfrozen to partially frozen, deeply frozen, and thawed) associated with natural seasonal freeze-thaw conditions. Treated and untreated biopiles were constructed (~3500kg each) on an open outdoor surface at a remediation facility in Saskatoon, Canada. The treated biopile received N-P-K-based nutrient and humate amendments before seasonal freezing. Real-time field monitoring indicated significant unfrozen water content in the treated and untreated biopiles throughout the freezing period, from the middle of November to early March. Unfrozen water was slightly more available in the treated biopile due to the aqueous nutrient supply. Soil CO2 production and O2 consumption in the treated biopile were generally greater than in the untreated biopile. Total removal percentages for F2 (>C10–C16), F3 (>C16–C34), and total petroleum hydrocarbons (TPH) in the treated biopile were 57, 58, and 58%, respectively, of which 26, 39, and 33% were removed during seasonal freezing and early thawing between November to early March. F3 degradation largely occurred during freezing while F2 hydrocarbons were primarily removed during thawing. Biomarker-based hydrocarbon analyses confirmed enhanced biodegradation in the treated biopile during freezing. The soil treatment increased the first-order rate constants for F2, F3, and TPH degradation by a factor of 2 to 7 compared to the untreated biopile. Shifts in bacterial community appeared in both biopiles as the biopile soils seasonally froze and thawed. Increased alkB1 gene copy numbers in the treated biopile, especially in the partially thawed phase during early thawing, suggest extended hydrocarbon biodegradation to the seasonal freeze-thaw season, due to the nutrients supplied prior to seasonal freezing.

Biostimulation of n-Alkane Degradation in Diesel Fuel-Spiked Soils

ABSTRACTNutrient enhancement of bioremediation with nitrogen, namely biostimulation, increases process performance. Selection of a proper nitrogen source is critical for bioremediation applications. In this study, the effects of different nitrogen sources on biodegradation of C10–C25 n-alkane compounds in diesel fuel-spiked soil were revealed, and the most appropriate nitrogen source for biodegradation of semi- and non-volatile n-alkanes was investigated. Bioremediation of diesel fuel contaminated soil was monitored in lab-scale reactors for 15 days. Ammonium sulfate, potassium nitrate and urea were used as nitrogen sources. Carbon dioxide and oxygen levels in the reactors were recorded to monitor microbiological activity. Contaminant removal process was investigated by pH, heterotrophic plate count, total petroleum hydrocarbons (TPH) and C10–C25 n-alkane analyses. First-order kinetic constants were calculated via respirometric and contaminant concentration data. According to total C10–C25 n-alkane removal levels and degradation rate constants, ammonium sulfate addition resulted in the most efficient contaminant removal followed by potassium nitrate and urea. Simultaneous degradation of individual n-alkanes was observed for all of the nitrogen sources. Urea addition changed the distribution of individual n-alkane concentrations relative to the pre-experimental concentrations. Nitrogen source type had no differential effect on degradation rates of semi- (C10–C16) and non-volatile (C17–C25) fractions.

Effect of Cu promotion on cracking and methanation during the Ni-catalyzed deoxygenation of waste lipids and hemp seed oil to fuel-like hydrocarbons

Deoxygenation of yellow grease and hemp seed oil was studied over 20% Ni/Al2O3 and 20% Ni-5% Cu/Al2O3 catalysts in the presence of H2. In the deoxygenation of 25wt% yellow grease (dissolved in dodecane) both catalysts afforded a liquid product consisting of mainly linear C10–C17 alkanes; however, the Cu-promoted catalyst showed improved selectivity to long chain (C15–C17) hydrocarbons as a result of its lower cracking activity. Analysis of the light hydrocarbon products (C10–C16) showed that cracking mainly occurred via the removal of terminal carbons (with methane formation), although a small amount of internal cracking also occurs based on the presence of C6–C11 in the product mixtures. Similar improvements were also observed in the deoxygenation of 25wt% hemp seed oil, showing that Cu was able to curb cracking even when a highly unsaturated feed was employed. The Cu promotion effect was more pronounced in the deoxygenation of 75wt% yellow grease in which the 20% Ni/Al2O3 catalyst did not yield any liquid products, whereas the 20% Ni-5% Cu/Al2O3 catalyst afforded liquid products consisting of >90% diesel-like hydrocarbons.

Catalytic Determinants of Alkene Production by the Cytochrome P450 Peroxygenase OleTJE

The Jeotgalicoccus sp. peroxygenase cytochrome P450 OleTJE (CYP152L1) is a hydrogen peroxide-driven oxidase that catalyzes oxidative decarboxylation of fatty acids, producing terminal alkenes with applications as fine chemicals and biofuels. Understanding mechanisms that favor decarboxylation over fatty acid hydroxylation in OleTJE could enable protein engineering to improve catalysis or to introduce decarboxylation activity into P450s with different substrate preferences. In this manuscript, we have focused on OleTJE active site residues Phe79, His85, and Arg245 to interrogate their roles in substrate binding and catalytic activity. His85 is a potential proton donor to reactive iron-oxo species during substrate decarboxylation. The H85Q mutant substitutes a glutamine found in several peroxygenases that favor fatty acid hydroxylation. H85Q OleTJE still favors alkene production, suggesting alternative protonation mechanisms. However, the mutant undergoes only minor substrate binding-induced heme iron spin state shift toward high spin by comparison with WT OleTJE, indicating the key role of His85 in this process. Phe79 interacts with His85, and Phe79 mutants showed diminished affinity for shorter chain (C10–C16) fatty acids and weak substrate-induced high spin conversion. F79A OleTJE is least affected in substrate oxidation, whereas the F79W/Y mutants exhibit lower stability and cysteine thiolate protonation on reduction. Finally, Arg245 is crucial for binding the substrate carboxylate, and R245E/L mutations severely compromise activity and heme content, although alkene products are formed from some substrates, including stearic acid (C18:0). The results identify crucial roles for the active site amino acid trio in determining OleTJE catalytic efficiency in alkene production and in regulating protein stability, heme iron coordination, and spin state.

Role of the Catalyst in the Pyrolysis of Polyolefin Mixtures and Used Tires

The role of polymeric structures and the presence of a catalyst in the pyrolysis of polyolefin mixtures and used tires was studied in a fixed bed reactor at 450 °C. Our results showed that while thermal pyrolysis of high density polyethylene (HDPE) produced 23.3%wt of condensable products, a mixture of polyolefins (HDPE, LDPE, and PP) showed an increase of more than 23%wt in this fraction. In both cases, a wide carbon number distribution was obtained for the condensable products, confirming that there was not any selectivity. By using HZSM-5 zeolites, the pyrolysis of pure HDPE was dramatically changed with both more gaseous products and a major selectivity toward C10–C16 hydrocarbons in the condensable fraction. It is noteworthy that, although the PP present in the mixture increases the production of lighter hydrocarbons as compared with pure HDPE, no major differences in product distribution were observed between HDPE and polyolefin mixture in catalytic pyrolysis. However, the zeolites used improved the...

Dispersion, sorption and photodegradation of petroleum hydrocarbons in dispersant-seawater-sediment systems

This work examined effects of model oil dispersants on dispersion, sorption and photodegradation of petroleum hydrocarbons in simulated marine systems. Three dispersants (Corexit 9500A, Corexit 9527A and SPC 1000) were used to prepare dispersed water accommodated oil (DWAO). While higher doses of dispersants dispersed more n-alkanes and PAHs, Corexit 9500A preferentially dispersed C11–C20 n-alkanes, whereas Corexit 9527A was more favorable for smaller alkanes (C10–C16), and SPC 1000 for C12–C28 n-alkanes. Sorption of petroleum hydrocarbons on sediment was proportional to TPH types/fractions in the DWAOs. Addition of 18mg/L of Corexit 9500A increased sediment uptake of 2–3 ring PAHs, while higher dispersant doses reduced the uptake, due to micelle-enhanced solubilization effects. Both dispersed n-alkanes and PAHs were susceptible to photodegradation under simulated sunlight. For PAHs, both photodegradation and photo-facilitated alkylation were concurrently taking place. The information can facilitate sounder assessment of fate and distribution of dispersed oil hydrocarbons in marine systems.

Anchoring via covalent binding of β-diimine-nickel complexes in SBA-15 and its application in catalytic reactions

The β-diimine ligands 2-(phenyl)amine-4-(phenyl)imine-2-pentene (L1) and 2-(2,6-dimethylphenyl)amine-4-(2,6-dimethylphenyl)imine-2-pentene (L2) were anchored covalently to SBA-15. The ligands were combined with (3-chloropropyl) trimethoxysilane (CPTMS), which is a trialkoxysilane group, and anchored to a mesoporous SBA-15 support through a complexation of the silanols of the silica matrix with nickel. These complexes were synthesized as catalysts precursors for ethylene and propylene oligomerization processes. The support was first synthesized and calcined before being anchored to the ligand, generating the nickel complex. These materials were characterized using various techniques such as 13C and 29Si NMR, small angle XRD, thermogravimetric analysis, N2 adsorption, transmission electron microscopy, elemental analysis and flame atomic absorption spectroscopy. The heterogenized complexes are active and selective during ethylene and propylene oligomerization, generating C4 and C6 products and alkylation products ranging from C10–C16. The alkylation process being a parallel reaction. The Ni-β-diimine/SBA-15 (SC1) complexes showed an activity of 7.2×103h−1 for the ethylene oligomerization with 98% selectivity toward α- and C4 products and an activity of 2×103h−1for the propylene oligomerization with a 13% selectivity toward C6 linear products. The results of the oligomerization reactions reveal the influence of the support on the products obtained.

Milk fatty acid composition and mammary lipogenic genes expression in bovine cloned and control cattle

In order to understand the effect of nuclear transfer technology on the physiology of lactation and milk fatty acid composition in dairy cattle (Holstein breed), the present study compares the milk yield and composition from bovine somatic cell cloned (n=5) and control animals (n=5) at 180 days in milk (DIM) maintained together under the same conditions. All cows were offered the same total mixed ration ad libitum. At 180 DIM, the cloned had a higher body weight (BW; P<0.01) compared with control animals, whereas comparable body condition score (BCS) was observed among the 2 groups. The cloned cows had a lower milk yield and milk protein and lactose yields (P<0.05) and had a tendency (P=0.08) for a lower milk fat yield. Conversely, no differences in milk fat, protein and lactose concentrations were observed in cloned compared with control animals. Similar milk fatty acid (FA) concentrations were observed in cloned and control cows except for two minor FA, cis-9 C10:1 and C17:0 (P<0.05) that were higher in the cloned. The milk fat cis-9 C14:1/C14:0, cis-9 C16:1/C16:0, cis-9 C18:1/C18:0, cis-9, trans-11 C18:2/trans-11 C18:1 concentrations ratios were not different in cloned and control. The milk medium-(C10–C16) and long-(∑C18) chain FA yields were lower (P<0.05) in cloned compared with control animals. The mRNA abundance of genes encoding for SCD1, SCD5, ACACA and FABP3 genes in mammary tissue was similar (P>0.05) in cloned and non-cloned animals. Conversely, cloned animals had a lower (P<0.05) mRNA abundance of LPL and a tendency (P<0.10) for lower mRNA abundance of FASN and CD36 genes compared with control. The absence of major differences of milk constituent concentrations, milk FA composition and of the SCD desaturation indices observed between cloned and conventional animals suggest a comparable nutritional quality of milk for these animals. The noticed differences in milk long chain-FA yields were consistent with modulation of mammary lipogenic pathway as suggested by lower mRNA abundance of LPL gene in cloned compared with control. Otherwise, differences in the partitioning of nutrients between the mammary gland and other tissues cannot be excluded as suggested by the higher BW and lower milk yield observed in cloned. Altogether, these observations may be attributed to different genetic background and/or to epigenetic modifications due to the nuclear transfer technology that may affect the growth and the physiological adaptation to lactation and impact the dairy performances. Further investigations are required to identify the mechanisms underlying these differences.

Thermo-catalytic degradation of low density polyethylene to liquid fuel over kaolin catalyst

Waste low-density polyethylene samples were subjected to thermo-catalytic degradation using kaolin as catalyst in a batch reactor at temperature range of 400 to 500°C and atmospheric pressure. The quality and yield of the condensable product has been studied as a function of temperature and amount of catalyst. Both in thermal and catalytic degradation, the condensable fraction was less viscous liquid oil at low temperatures (up to 450°C), whereas with increase of temperature (from 475°C) the fraction became viscous and waxy. The recovery of condensable fraction increased from 30.8 wt.% at 400°C to 71.45% at 450°C and further increased to a maximum of 86.65wt.% at 500°C in absence of catalyst. The catalyst increased the yield of the condensable product and decreased the reaction time. The highest yield of liquid fraction at 450°C was 79.5 wt.% with 1:2 catalyst to plastics ratio. The composition of the oil obtained at optimum reaction condition was characterised by gas chromatography-mass spectroscopy (and found consisting of paraffins and olefins with mainly C10–C16 components. Fuel properties of the oil obtained by different standard methods are similar to petrochemical fuels.