The Underlying Catalytic Role of Oxygen Vacancies in Fatty Acid Methyl Esters Ketonization over TiOx Catalysts

Recently, interest in converting bio-derived fatty acid methyl esters (FAMEs) into added-value products has significantly increased. The selectivity of ketonization reaction in the conversion of the FAMEs has significantly hampered the efficiency of this process. Herein, this work reports the preparation of catalysts with different levels of oxygen vacancies while the crystal phase remained unchanged. The catalyst with the highest level of oxygen vacancy exhibited the maximum selectivity. The density functional theory (DFT) simulation showed an increase in interatomic distances leading to the formation of frustrated Lewis pairs (FLPs) upon the creation of oxygen vacancies. The surface measurements, type and density of acid sites of the catalysts, showed that the Lewis acid sites enhanced the selectivity for ketone production; while Bronsted acid sites increased the formation of by-products. Moreover, the ketone formation rate was directly proportional to acid density. The findings of this research provide a different approach for catalyst design, based on defects engineering and their effect on the surface activity, which could be used for enhancing the catalytic performance of novel metal oxides.

Comparative modelling, molecular docking and immobilization studies on Rhizopus oryzae lipase: evaluation of potentials for fatty acid methyl esters synthesis

Elucidation of lipase-substrate interactions will guide the proper industrial use and applicability of the enzyme. The aim of this study was to predict the 3 D structure of Rhizopus oryzae ZAC3 (RoZAC3) lipase, study its interactions with some natural substrates and evaluate the feasibility of fatty acid methyl esters (FAME) production by the immobilized lipase. Protein identification of RoZAC3 lipase was carried out using LC-MS/MS. The 3 D structure of the lipase was built using homology modelling and natural substrates such as tributyrin, tripalmitin and triolein were docked to the optimized 3 D model for investigation of enzyme-ligand interactions. RoZAC3 lipase, immobilized by adsorption on Lewatit VP OC 1600 was applied in the synthesis of fatty acid methyl esters (FAME). From the phylogenetic analysis, it was observed that RoZAC3 lipase was closely related (48%) to Rhizopus javanicus lipase (Q7M4U7). The predicted 3 D model was validated using the SWISS model validation server. Ramachandran and ERRAT plots were used to assess the amino acid environment and overall quality of the model. From the docking studies, the values of the binding energies obtained for tributyrin, tripalmitin and triolein were - 5.37, -5.27 and -5.77 respectively. At an enzyme:immobilization support ratio of 50 mg/g, transesterification reaction duration of 18 h and a temperature of 40 oC, the conversion reached above 80%. The molecular docking studies provided information on the interaction/modifications between the RoZAC3 lipase and triacylglycerols that can be exploited for numerous applications. The immobilized lipase could serve in hydro-esterification reactions adaptable for biodiesel production.Communicated by Ramaswamy H. Sarma.

Growth Behavior, Biomass Composition and Fatty Acid Methyl Esters (FAMEs) Production Potential of Chlamydomonas reinhardtii, and Chlorella vulgaris Cultures

The production of biomolecules by microalgae has a wide range of applications in the development of various materials and products, such as biodiesel, food supplements, and cosmetics. Microalgae biomass can be produced using waste and in a smaller space than other types of crops (e.g., soja, corn), which shows microalgae's great potential as a source of biomass. Among the produced biomolecules of greatest interest are carbohydrates, proteins, lipids, and fatty acids. In this study, the production of these biomolecules was determined in two strains of microalgae (Chlamydomonas reinhardtii and Chlorella vulgaris) when exposed to different concentrations of nitrogen, phosphorus, and sulfur. Results show a significant microalgal growth (3.69 g L-1) and carbohydrates (163 mg g-1) increase in C. reinhardtii under low nitrogen concentration. Also, higher lipids content was produced under low sulfur concentration (246 mg g-1). It was observed that sulfur variation could affect in a negative way proteins production in C. reinhardtii culture. In the case of C. vulgaris, a higher biomass production was obtained in the standard culture medium (1.37 g L-1), and under a low-phosphorus condition, C. vulgaris produced a higher lipids concentration (248 mg g-1). It was observed that a low concentration of nitrogen had a better effect on the accumulation of fatty acid methyl esters (FAMEs) (C16-C18) in both microalgae. These results lead us to visualize the effects that the variation in macronutrients can have on the growth of microalgae and their possible utility for the production of microalgae-based subproducts.

Fungistatic Effect of Phthalide Lactones on Rhodotorula mucilaginosa

Currently, there is an increasing number of cases of fungal infections caused by opportunistic strains of the yeast Rhodotorula mucilaginosa, mainly in immunocompromised patients during hospitalization. The excessive use of antibiotics and azole compounds increases the risk of resistance to microorganisms. A new alternative to these drugs may be synthetic phthalide lactones with a structure identical to or similar to the natural ones found in celery plants, which show low toxicity and relatively high fungistatic activity. In the present study, the fungistatic activity of seven phthalide lactones was determined against R. mucilaginosa IHEM 18459. We showed that 3-n-butylidenephthalide, the most potent compound selected in the microdilution test, caused a dose-dependent decrease in dry yeast biomass. Phthalide accumulated in yeast cells and contributed to an increase in reactive oxygen species content. The synergistic effect of fluconazole resulted in a reduction in the azole concentration required for yeast inhibition. We observed changes in the color of the yeast cultures; thus, we conducted experiments to prove that the carotenoid profile was altered. The addition of lactones also triggered a decline in fatty acid methyl esters.

Impact of Ascorbic Acid on Zero-Valent Iron Nanoparticle and UV-B Mediated Stress in the Cyanobacterium, Fremyella diplosiphon

Fremyella diplosiphon is an ideal third-generation biofuel source due to its ability to produce transesterified lipids. While nanofer 25s zero-valent iron nanoparticles (nZVIs) improve lipid production, an imbalance between reactive oxygen species (ROS) and cellular defense can be catastrophic to the organism. In the present study, the effect of ascorbic acid on nZVI and UV-induced stress in F. diplosiphon strain B481-SD was investigated, and lipid profiles in the combination regimen of nZVIs and ascorbic acid compared. Comparison of F. diplosiphon growth in BG11 media amended with 2, 4, 6, 8, and 10 mM ascorbic acid indicated 6 mM to be optimal for the growth of B481-SD. Further, growth in 6 mM ascorbic acid combined with 3.2 mg/L nZVIs was significantly higher when compared to the combination regimen of 12.8 and 51.2 mg/L of nZVIs and 6 mM ascorbic acid. The reversal effect of UV-B radiation for 30 min and 1 h indicated that ascorbic acid restored B481-SD growth. Transesterified lipids characterized by gas chromatography-mass spectrometry indicated C16 hexadecanoate to be the most abundant fatty acid methyl ester in the combination regimen of 6 mM ascorbic acid and 12.8 mg/L nZVI-treated F. diplosiphon. These findings were supported by microscopic observations in which cellular degradation was observed in B481-SD cells treated with 6 mM ascorbic acid and 12.8 mg/L nZVIs. Our results indicate that ascorbic acid counteracts the damaging effect of oxidative stress produced by nZVIs.

Evaluation of NMR predictors for accuracy and ability to reveal trends in 1 H NMR spectra of fatty acids

Four different nuclear magnetic resonance (NMR) predictors have been evaluated for their ability to predict 600-MHz ¹ H spectra of free fatty acids and fatty acid methyl esters of 20 common fatty acids. The predictors were evaluated on two main criteria: (1) their accuracy in direct prediction of the spectra (absolute accuracy) and (2) the ability to reveal trends or predict the change that occurs in the spectra as a result of a change in the fatty acid carbon chain, or by esterification of the free fatty acids to methyl esters (relative accuracy). The absolute accuracy in chemical shift prediction for fatty acids was good, compared with previous reports on a broader range of compounds. All four predictors had median prediction errors for chemical shifts of the signals in fatty acid methyl esters well below 0.1 ppm and as low as 0.015 ppm for one of the predictors. However, all predictors also had outliers with errors far above the upper interquartile range. In general, they also fail to reproduce trends of diagnostic value that were observed in the experimental data or properly predict the result of a minor change in molecular structure. All four predictors depend on experimental data from different origins. This may be a limiting factor for the relative accuracy of the predictors.

Monitoring tert-Butylhydroquinone Content and Its Effect on a Biolubricant during Oxidation

The use of biolubricants as a replacement for petroleum-based products is becoming more and more important, due to the current global energy and crude oil scenario. Thus, the production of biolubricants (which could take place in biorefineries) should be as efficient as possible, obtaining high-quality products with suitable viscosity or oxidation stability values to compete with oil refineries. One of the ways to produce biolubricants is through double transesterification from vegetable oils, where the role of catalysts (usually homogeneous) is vital, as they can improve the yield of the process. However, they should be removed after the chemical reaction, which is difficult once the biolubricant is obtained. Otherwise, they could act as catalysts during oxidation, contributing to a further decrease in oxidation stability and provoking significant changes. To avoid this, antioxidant addition could be an interesting choice. The aim of this work was to assess TBHQ addition in frying oil biolubricants, monitoring properties such as viscosity, acid number, absorbance or TBHQ content (through voltammetry) during oxidation. TBHQ addition (2114 mg·L^-1) kept the main quality parameters during oxidation compared to control samples. In contrast, TBHQ content decreased during oxidation (to 160 mg·L^-1), which proved its antioxidant effect.

High Epoxidation Yields of Vegetable Oil Hydrolyzates and Methyl Esters by Selected Fungal Peroxygenases

Epoxides of vegetable oils and free and methylated fatty acids are of interest for several industrial applications. In the present work, refined rapeseed, sunflower, soybean, and linseed oils, with very different profiles of mono- and poly-unsaturated fatty acids, were saponified and transesterified, and the products treated with wild unspecific peroxygenases (UPOs, EC 1.11.2.1) from the ascomycete Chaetomium globosum (CglUPO) and the basidiomycete Marasmius rotula (MroUPO), as well as with recombinant UPO of the ascomycete Humicola insolens (rHinUPO), as an alternative to chemical epoxidation that is non-selective and requires strongly acidic conditions. The three enzymes were able of converting the free fatty acids and the methyl esters from the oils into epoxide derivatives, although significant differences in the oxygenation selectivities were observed between them. While CglUPO selectively produced "pure" epoxides (monoepoxides and/or diepoxides), MroUPO formed also hydroxylated derivatives of these epoxides, especially in the case of the oil hydrolyzates. Hydroxylated derivatives of non-epoxidized unsaturated fatty acids were practically absent in all cases, due to the preference of the three UPOs selected for this study to form the epoxides. Moreover, rHinUPO, in addition to forming monoepoxides and diepoxides of oleic and linoleic acid (and their methyl esters), respectively, like the other two UPOs, was capable of yielding the triepoxides of α-linolenic acid and its methyl ester. These enzymes appear as promising biocatalysts for the environmentally friendly production of reactive fatty-acid epoxides given their self-sufficient monooxygenase activity with selectivity toward epoxidation, and the ability to epoxidize, not only isolated pure fatty acids, but also complex mixtures from oil hydrolysis or transesterification containing different combinations of unsaturated (and saturated) fatty acids.

Halomonas icarae sp. nov., a moderately halophilic bacterium isolated from beach soil in India

A moderately halophilic, Gram-stain-negative, aerobic bacterium, strain D1-1^T, belonging to the genus Halomonas, was isolated from soil sampled at Pentha beach, Odisha, India. Phylogenetic trees reconstructed based on 16S rRNA genes and multilocus sequence analysis of gyrB and rpoD genes revealed that strain D1-1^T belonged to the genus Halomonas and was most closely related to Halomonas alimentaria YKJ-16^T (98.1 %) followed by Halomonas ventosae Al12^T (97.5 %), Halomonas sediminicola CPS11^T (97.5 %), Halomonas fontilapidosi 5CR^T (97.4 %) and Halomonas halodenitrificans DSM 735^T (97.2 %) on the basis of 16S rRNA gene sequence similarity. Sequence identities with other species within the genus were lower than 97.0 %. The digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values of 22.4-30 % and 79.5-85.4 % with close relatives of H. halodenitrificans DSM 735^T, H. alimentaria YKJ-16^T, H. ventosae Al12^T and H. fontilapidosi 5CR^T were lower than the threshold recommended for species delineation (70 % and 95-96 % for dDDH and ANI, respectively). Further, strain D1-1^T formed yellow-coloured colonies; cells were rod-shaped, motile with optimum growth at 30 °C (range, 4-45 °C) and 2-8 % NaCl (w/v; grew up to 24 % NaCl). The major fatty acids were summed feature 8 (C_18 : 1  ω7c/C_18 : 1  ω6c), summed feature 3 (C_16 : 1  ω7c/C_16 : 1  ω6c) and C_16 : 0 and the main respiratory quinone was ubiquinone Q-9 in line with description of the genus. Based on its chemotaxonomic and phylogenetic characteristics and genome uniqueness, strain D1-1^T represents a novel species in the genus Halomonas, for which we propose the name Halomonas icarae sp. nov., within the family Halomonadaceae. The type strain is D1-1^T (=JCM 33602^T=KACC 21317^T=NAIMCC-B-2254^T).

Epoxidation of Fatty Acid Methyl Esters Derived from Algae Biomass to Develop Sustainable Bio-Based Epoxy Resins

The objective of this research was to investigate the development of epoxides from Chlorella vulgaris lipids to obtain a novel bio-based resin. The process involved the production of fatty acid methyl esters (FAMEs) by in situ transesterification of microalgal biomass, followed by epoxidation of the FAMEs to obtain bioresin. During the FAME production process, an assessment was made of the main factors affecting the production of unsaturated fatty acid methyl esters (UFAMEs), such as catalyst dosage and methanol:hexane volume ratio. For step epoxidation, an evaluation of the catalyst concentration, temperature and formic acid:hydrogen peroxide ratio was made. From the results obtained, UFAME production was maximized using 20 wt% of catalyst dosage and a volume ratio of 1:2 (v/v, methanol:hexane). Then, in the epoxidation stage, a higher yield was obtained using 1 wt% of catalyst with a volume ratio of 1:1 and maintaining a temperature of 70 °C. The bioresin was blended with neat epoxy resin (DGEBA) and cured with tetraethylenepentamine (TEPA). Bio-based resin was characterized via Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA) to evaluate this material as an alternative source for oleochemistry.

Profiling the Lipophilic Fractions of Pithecellobium dulce Bark and Leaves Using GC/MS and Evaluation of Their Antioxidant, Antimicrobial and Cytotoxic Activities

Pithecellobium dulce has been used in traditional medicine to treat various ailments owing to its restorative properties. The biological activities and chemical profiles of the lipophilic fraction of P. dulce bark and leaves were assessed herein. Fatty acid methyl esters (FAME) and unsaponifiable matter (USM) were prepared and analyzed by GC/MS. A total of 40 compounds were identified in the bark saponifiable fraction, whereas 9 compounds were annotated in the leaves. Palmitic acid methyl ester was the major compound identified accounting for 41.48 % of the bark and 19.03 % of the leaves composition. Besides, linolenic acid methyl ester (22.40 %) and linoleic acid (12.69 %) were annotated in the leaves saponifiable fraction. A total of 63 compounds were detected in the bark USM and 4 compounds were identified in the leaves. Phytol represented the major component in the leaves (52.57 %) followed by lupeol (20.68 %) and lupenone (8.60 %). Meanwhile, n-dodecane dominated in the bark USM accounting for 24.69 % of the total composition. The leaves and bark lipophilic fractions revealed moderate antioxidant and antibacterial activities. Both extracts showed no antifungal activity. No cytotoxicity was observed for both lipophilic fractions. P. dulce offers a good source of antioxidant compounds that can be introduced to food and pharmaceutical industry.

Volatile, Sensory and Functional Properties of HydroSOS Pistachios

Climate change, the increase in world population, and the intensification of urban and industrial activities, will cause a shortage of water for agriculture. This situation requires conscientious studies to manage water deficits without affecting the quality of the crops. In this study, regulated deficit irrigation (RDI) strategies and three rootstocks (P. atlantica, P. integerrima, and P. terebinthus) were applied to pistachio cultivation to study the quality of fruits obtained based on the morphological, functional, aroma, and their sensory properties. The results obtained demonstrated that RDI T1 (during phenological phase II of cultivation the stem water potential was maintained around −1.5 MPa) led to pistachios with same morphological properties, total polyphenol content, antioxidant activity, volatile composition, sensory properties, better profile of fatty acids, and being the favorite ones for international consumers, as compared to pistachios obtained under full irrigation treatments. On the other hand, when P. integerrima was used, pistachios obtained had the highest weight, the lowest content of sucrose and the best functional properties.

Utilization of Clarified Butter Sediment Waste as a Feedstock for Cost-Effective Production of Biodiesel

The rising demand and cost of fossil fuels (diesel and gasoline), together with the need for sustainable, alternative, and renewable energy sources have increased the interest for biomass-based fuels such as biodiesel. Among renewable sources of biofuels, biodiesel is particularly attractive as it can be used in conventional diesel engines without any modification. Oleaginous yeasts are excellent oil producers that can grow easily on various types of hydrophilic and hydrophobic waste streams that are used as feedstock for single cell oils and subsequently biodiesel production. In this study, cultivation of Rhodosporidium kratochvilovae on a hydrophobic waste (clarified butter sediment waste medium (CBM)) resulted in considerably high lipid accumulation (70.74% w/w). Maximum cell dry weight and total lipid production were 15.52 g/L and 10.98 g/L, respectively, following cultivation in CBM for 144 h. Neutral lipids were found to accumulate in the lipid bodies of cells, as visualized by BODIPY staining and fluorescence microscopy. Cells grown in CBM showed large and dispersed lipid droplets in the intracellular compartment. The fatty acid profile of biodiesel obtained after transesterification was analyzed by gas chromatography-mass spectrometry (GC–MS), while its quality was determined to comply with ASTM 6751 and EN 14214 international standards. Hence, clarified sediment waste can be exploited as a cost-effective renewable feedstock for biodiesel production.

Lipid metabolism alterations in the neuronal response to A53T α-synuclein and Fe-induced injury

Pathological α-synuclein (α-syn) overexpression and iron (Fe)-induced oxidative stress (OS) are involved in the death of dopaminergic neurons in Parkinson's disease (PD). We have previously characterized the role of triacylglycerol (TAG) formation in the neuronal response to Fe-induced OS. In this work we characterize the role of the α-syn variant A53T during Fe-induced injury and investigate whether lipid metabolism has implications for neuronal fate. To this end, we used the N27 dopaminergic neuronal cell line either untransfected (UT) or stably transfected with pcDNA3 vector (as a transfection control) or pcDNA-A53T-α-syn (A53T α-syn). The overexpression of A53T α-syn triggered an increase in TAG content mainly due to the activation of Acyl-CoA synthetase. Since fatty acid (FA) β-oxidation and phospholipid content did not change in A53T α-syn cells, the unique consequence of the increase in FA-CoA derivatives was their acylation in TAG moieties. Control cells exposed to Fe-induced injury displayed increased OS markers and TAG content. Intriguingly, Fe exposure in A53T α-syn cells promoted a decrease in OS markers accompanied by α-syn aggregation and elevated TAG content. We report here new evidence of a differential role played by A53T α-syn in neuronal lipid metabolism as related to the neuronal response to OS.

Chromatographic efficiency of polar capillary columns applied for the analysis of fatty acid methyl esters by gas chromatography

The chromatographic efficiency that could be achieved in temperature-programmed gas chromatography was compared for four capillary columns that are typically applied for analysis of fatty acid methyl esters (FAME). Three different carrier gases, hydrogen, helium and nitrogen, were applied. For each experiment, the carrier gas velocities and the temperature rates were varied with a full 9 × 3 design, with nine levels on the carrier gas velocity and temperature rates of 1, 2 or 3°C/min. Response surface methodology was used to create models of chromatographic efficiency as a function of temperature rate and carrier gas velocity. The chromatographic efficiency was defined as the inverse of peak widths measured in retention index units. The final results were standardized so that the efficiencies that could be achieved within a certain time frame, defined by the retention time of the last compound in the chromatogram, could be compared. The results show that there were clear differences in the efficiencies that could be achieved with the different columns and that the efficiency decreased with increasing polarity of the stationary phase. The differences can be explained by higher resistance to mass transfer in the stationary phase in the most polar columns.

Experimental and numerical investigations on spray characteristics of fatty acid methyl esters

A comparative experimental and numerical study is conducted to establish the significance of the use of single-component over multi-component representatives of biodiesel, diesel and their blend for predicting spray tip penetration. Methyl oleate and methyl laurate are used as single-component representative fuels for biodiesel. The pure components n-heptane, n-dodecane and n-tetradecane are used as single-component representative fuels for diesel. Methyl laurate is found to represent biodiesel of coconut, whereas methyl oleate is found to represent biodiesel having high percentage of long-chain fatty acid esters. The spray tip penetration of methyl oleate is found to be in good agreement with the measured spray tip penetration of karanja biodiesel. The spray tip penetration prediction of n-heptane fuel is closely following diesel spray tip penetration along with that of n-tetradecane and n-dodecane. The study suggests that the knowledge of the single-component representatives of biodiesel, diesel and their blend is sufficient to predict the spray tip penetration of the corresponding biodiesel, diesel and their blend under non-evaporating environment.

Influence of High Temperature and Duration of Heating on the Sunflower Seed Oil Properties for Food Use and Bio-diesel Production

Two important problems for the food industry are oil oxidation and oil waste after frying. Sunflower seed oil is one of the vegetable oils most commonly used in the food industry. Two variables were applied to the low oleic sunflower seed oil in this work i.e. heating temperature (180-210-240°C) and time of heating (15-30-60-120 minutes), to study from the edible point of view the variations of its physico-chemical properties. After 120 minutes heating at 240°C the following was found: refractive index (1.476), free acidity (0.35%), K232 (2.87), K270 (3.71), antiradical activity (45.90% inhibition), total phenols (523 mg kg^-1), peroxide value (17.00 meq kg^-1), p-anisidine value (256.8) and Totox (271.7), all of which showed a constant deterioration. In relation to the use as a feedstock for bio-diesel production, after 120 minutes heating at 240℃ the following was found: acid value 0.70 mg KOH g^-1 oil, iodine value 117.83 g I₂ 100 g^-1 oil, oil stability index 0.67 h, kinematic viscosity (at 40°C) 77.85 mm² s^-1, higher heating value 39.86 MJ kg^-1, density 933.34 kg/m³ and cetane number 67.04. The parameters studied in this work were influenced, in different ways, by the applied variables. Heating temperature between 180 and 210°C and 120 min heating duration were found to be the most appropriate conditions for sunflower seed oil both from the deep frying point of view and from a subsequent use as feedstock for bio-diesel production. In light of the vegetable oils' International standards for an edible use and for a bio-diesel production, findings of this work can be used to set heating temperature and heating duration to preserve as long possible the physico-chemical properties of a low oleic sunflower seed oil for both its edible use as a fat during cooking and for its re-use after frying.

Fictibacillus aquaticus sp. nov., isolated from downstream river water

A Gram-stain-positive, facultatively anaerobic bacterial strain, GDSW-R2A3^T, was isolated from a downstream water sample collected from the river Ganges, India. Analysis of the 16S rRNA gene sequence of strain GDSW-R2A3^T revealed its affiliation to the family Bacillaceae. Further analysis using a polyphasic approach revealed that strain GDSW-R2A3^T was most closely related to the genus Fictibacillus. Analysis of the almost-complete (1488 bp) 16S rRNA gene sequence of strain GDSW-R2A3^T revealed the highest level of sequence similarity with Fictibacillus phosphorivorans CCM 8426^T (98.3 %) and Fictibacillus nanhaiensis KCTC 13712^T (98.3 %) followed by Fictibacillus barbaricus DSM 14730^T (98.0 %). The digital DNA-DNA hybridization and average nucleotide identity (ANI) values between strain GDSW-R2A3^T and the most closely related taxon, F. phosphorivorans CCM 8426^T, were 20.3 and 78.2 %, respectively. The DNA G+C content of the strain was 44.2 mol%. The cell-wall amino acid was meso-diaminopimelic acid. Polar lipids present were phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, three aminophospholipids, two phospholipids and one unidentified lipid; the major menaquinone was MK-7; iso-C14 : 0, iso-C15 : 0 and anteiso-C15 : 0 were the major fatty acids. On the basis of the phenotypic, chemotaxonomic and phylogenetic data, it can be concluded that strain GDSW-R2A3^T represents a novel species of the genus Fictibacillus, for which the name Fictibacillus aquaticus sp. nov. is proposed. The type strain is GDSW-R2A3^T (=VTCC-B-910015^T=CCM 8782^T).

High protein- and high lipid-producing microalgae from northern australia as potential feedstock for animal feed and biodiesel

Microalgal biomass can be used for biodiesel, feed, and food production. Collection and identification of local microalgal strains in the Northern Territory, Australia was conducted to identify strains with high protein and lipid contents as potential feedstock for animal feed and biodiesel production, respectively. A total of 36 strains were isolated from 13 samples collected from a variety of freshwater locations, such as dams, ponds, and streams and subsequently classified by 18S rDNA sequencing. All of the strains were green microalgae and predominantly belong to Chlorella sp., Scenedesmus sp., Desmodesmus sp., Chlamydomonas sp., Pseudomuriella sp., Tetraedron caudatum, Graesiella emersonii, and Mychonastes timauensis. Among the fastest growing strains, Scenedesmus sp. NT1d possessed the highest content of protein; reaching up to 33% of its dry weight. In terms of lipid production, Chlorella sp. NT8a and Scenedesmus dimorphus NT8e produced the highest triglyceride contents of 116.9 and 99.13 μg mL(-1) culture, respectively, as measured by gas chromatography-mass spectroscopy of fatty acid methyl esters. These strains may present suitable candidates for biodiesel production after further optimization of culturing conditions, while their protein-rich biomass could be used for animal feed.

Cross-metathesis of biosourced fatty acid derivatives: a step further toward improved reactivity

The improved catalytic conversion of bioresources, namely unsaturated fatty acid derivatives, is presented. The targeted reaction is ruthenium-catalyzed cross-metathesis with functionalized olefins (α,β-unsaturated esters), that affords shorter diesters. These can be used as biosourced (pre)monomers for the production of polyesters. It is demonstrated that switch from terminal to internal cross-metathesis partners (that is, from methyl acrylate to methyl crotonate) allows use of ppm-level catalyst loadings, while retaining high productivity and selectivity. This was exemplified on a commercial biosourced fatty acid methyl esters mixture, using minimal purification of the substrate, on a 50 g scale. We propose that this improved catalytic behavior is due to the sole presence of more stable alkylidene intermediates, as the notoriously unstable ruthenium methylidene species are not formed using an internal functionalized olefin.

Fatty Acid Profiles for Differentiating Growth Medium Formulations Used to Culture Bacillus cereus T-strain Spores

Microbial biomarkers that indicate aspects of an organism's growth conditions are important targets of forensic research. In this study, we examined fatty acid composition as a signature for the types of complex nutrients in the culturing medium. Bacillus cereus T-strain spores were grown in medium formulations supplemented with one of the following: peptone (meat protein), tryptone (casein protein), soy protein, and brain-heart infusion. Cellular biomass was profiled with fatty acid methyl ester (FAME) analysis. Results showed peptone cultures produced spores enriched in straight-chained lipids. Tryptone cultures produced spores enriched in branched-odd lipids when compared with peptone, soy, and brain-heart formulations. The observed FAME variation was used to construct a set of discriminant functions that could help identify the nutrients in a culturing recipe for an unknown spore sample. Blinded classification tests were most successful for spores grown on media containing peptone and tryptone, showing 88% and 100% correct identification, respectively.

Determination of fatty acids and stable carbon isotopic ratio in subcutaneous fat to identify the feeding regime of Iberian pigs

Discrimination among the types of feeding regimes for Iberian pigs is currently a highly demanded challenge by the Iberian pig sector. In the present research, discrimination among feeding regimes has been achieved by the combination of two analytical methods (based on FAMEs analysis by GC-FID and determination of δ(13)C by IRMS) previously used independently without success. In the present study, 80 samples of adipose tissue from Iberian pigs subjected to four different feedings were analyzed. The study of the variables more influenced by the feeding regime has allowed us to configure panels of markers with predictive power for the studied feedings by multivariate ROC analysis. The results provided values of specificity and sensitivity higher than 85% in most cases. The statistical combination of results from different analytical methods could be the key to develop models for the correct discrimination of Iberian pigs according to the feeding regime.

Stimulation of nitrogen removal in the rhizosphere of aquatic duckweed by root exudate components

Plants can stimulate bacterial nitrogen (N) removal by secretion of root exudates that may serve as carbon sources as well as non-nutrient signals for denitrification. However, there is a lack of knowledge about the specific non-nutrient compounds involved in this stimulation. Here, we use a continuous root exudate-trapping system in two common aquatic duckweed species, Spirodela polyrrhiza (HZ1) and Lemna minor (WX3), under natural and aseptic conditions. An activity-guided bioassay using denitrifying bacterium Pseudomonas fluorescens showed that crude root exudates of the two species strongly enhanced the nitrogen-removal efficiency (NRE) of P. fluorescens (P < 0.05) under both conditions. Water-insoluble fractions (F) obtained under natural conditions stimulated NRE to a significant extent, promoting rates by about 30%. Among acidic, neutral and basic fractions, a pronounced stimulatory effect was also observed for the neutral fractions from HZ1 and WX3 under both conditions, whereas the acidic fractions from WX3 displayed an inhibitory effect. Analysis of the active fractions using gas chromatography/mass spectrometry (GC/MS) revealed that duckweed released fatty acid methyl esters and fatty acid amides, specifically: methyl hexadecanoate, methyl (Z)-7-hexadecenoate, methyl dodecanoate, methyl-12-hydroxystearate, oleamide, and erucamide. Methyl (Z)-7-hexadecenoate and erucamide emerged as the effective N-removal stimulants (maximum stimulation of 25.9 and 33.4%, respectively), while none of the other tested compounds showed stimulatory effects. These findings provide the first evidence for a function of fatty acid methyl esters and fatty acid amides in stimulating N removal of denitrifying bacteria, affording insight into the "crosstalk" between aquatic plants and bacteria in the rhizosphere.

Effects of fluctuating temperature and silicate supply on the growth, biochemical composition and lipid accumulation of Nitzschia sp

Nitzschia sp. (Bacillariophyceae) was grown under temperature and photoperiods mimicking those, typical during summer, spring/fall and winter conditions in the southern United States, and using five silicate (Si) concentrations. In general, higher Si concentrations resulted in higher growth rates in summer and spring/fall conditions and lower organic content. Si-deficient Nitzschia sp. had higher levels of neutral lipid compared to those growing in Si replete media. Under summer conditions, the proportion of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) was relatively stable compared with spring/fall and winter conditions, and the proportion of polyunsaturated fatty acids (PUFA) was low. In the winter condition, SFA and MUFA showed a gradient of decreasing abundance while PUFA gradients increased with increasing Si concentrations in the medium. Cumulative productivity (optimization of growth and lipid content) would be best in the spring/fall but less so in the other conditions for this strain of Nitzschia sp.

Characterization of an oleate 12-desaturase from Physaria fendleri and identification of 5'UTR introns in divergent FAD2 family genes

Mining of an EST sequence collection representing genes expressed during seed development in Physaria fendleri identified abundant sequences encoding apparent homologues of the Arabidopsis oleate 12-desaturase (AtFAD2 At3g12120). Of the 62 sequenced clones, 59 were identified as encoding the previously characterized bifunctional oleate 12-hydroxylase/desaturase (LFAH12/PfFAH12). The remaining 3 clones encoded a second FAD2 homologue. Isolation of a full length ORF and heterologous expression in yeast revealed that this sequence, designated PfFAD2, is the first full length sequence from any Physaria species that encodes an oleate 12-desaturase. PfFAD2 was expressed in both leaf and developing seed with activity on palmitate (16:1(Δ9)) and oleate (18:1(Δ9)). Sequence comparison revealed that PfFAD2 shares 93% amino acid identity with Arabidopsis FAD2 and only 84% identity with PfFAH12. By comparison of EST and genomic sequences it was revealed that the PfFAD2 gene encodes a transcript with a single intron of 1120 bp in the 5'-untranslated region (5'UTR). A short intron, 81 bp in length, was also discovered in the 5'UTR of the PfFAH12 gene, 16 bp upstream of the translation initiation codon. In silico examination of FAD2 like genes from the genome of castor (Ricinus communis) identified putative 5'UTR introns in genes encoding the castor oleate 12-desaturase (RcFAD2) and oleate 12-hydroxylase (CFAH12). By sequencing of genomic DNA the presence of single 5'UTR introns in each gene, and the size of these introns, was confirmed. These findings suggest that 5'UTR introns may be a characteristic feature of FAD2 genes and also of divergent FAD2 genes encoding fatty acid modifying enzymes, and that the selection pressure maintaining these introns is very different.

A novel and robust recombinant Pichia pastoris yeast whole cell biocatalyst with intracellular overexpression of a Thermomyces lanuginosus lipase: preparation, characterization and application in biodiesel production

A novel and robust recombinant Pichia pastoris yeast whole cell catalyst (WCC) with functional intracellular expression of Thermomyces lanuginosus lipase (Tll) was constructed and characterized for biodiesel production from waste cooking oils. This permeabilized WCC was able to convert waste cooking oils to biodiesel with 82% yield within 84 h at 6% dosage whole cells. The WCC showed two fold catalytic activity of 0.73 U/mg DCW compared to its commercial counterpart Lipozyme TLIM (immobilized Tll). Short chain alcohol tolerance of this WCC was significantly improved compared to Lipozyme TLIM. This beneficial property enabled it to catalyze biodiesel production efficiently with one step addition of methanol. The reusability of this biocatalyst retained 78% activity after three batch cycles. This easily prepared and cost-effective WCC showed better catalytic performance than Lipozyme TLIM with respect to biodiesel yield and productivity, thus suggesting a promising cost-effective biocatalyst for biodiesel production.

Effect of coagulant/flocculants on bioproducts from microalgae

The potential of microalgae as a source of sustainable energy, nutritional supplements and specialized chemicals necessitates a thorough evaluation of the methods of harvesting microalgae with regards to the bioproduct(s) desired. This research assessed the effect of coagulation, flocculation, and centrifugation on the wet lipid extraction procedure, which fractionated microalgae into hydrolyzed biomass for fermentation into acetone, butanol, and ethanol, an aqueous phase as growth media for genetically engineered Escherichia coli, and a lipid fraction for the production of biodiesel. Biomass harvested by cationic starches, alum, and centrifugation produced 30, 19, and 22.5mg/g of dry wt. algae of total combined acetone, butanol, and ethanol, respectively. Higher biodiesel production was also observed for the cationic starches (9.6 mg/g of dry wt. algae) than alum (0.6 mg/g of dry wt. algae) harvested biomass. The results suggested significant effect of the harvesting methods on the yields of bioproducts.

Induction of lipids and resultant FAME profiles of microalgae from coastal waters of Pearl River Delta

This article presents a study on identification, cultivation and characterisation of microalgal strains from the coastal waters of the Pearl River Delta in Guangdong, China. Thirty-seven identified strains belong to the families: Chlorellaceae, Scotiellocystoidaceae, Scenedesmaceae,Selenastraceae,Micractiniaceae, Coccomyxaceae, Trebouxiaceae and Chlorococcaceae. Of isolated strains, Hindakia PKUAC 169 was selected for lipid induction using two methods: nitrogen starvation and salt stress. After derivatisation of algal lipids through in situ transesterification, lipid profiles of the alga under the two methods were analysed. The results have shown that both lipid yield and fatty acid profiles vary with the methods. Of the two tested methods of inducing lipid production, salt stress yielded three-fold higher lipid productivity than nitrogen starvation. The lipids are predominantly composed of C14-C18 fatty acids, which are favourable for biodiesel production. Moreover, the content of polyunsaturated fatty acids was below the limit of 12% set by EN14214 biodiesel standard.

An integrated proteomic approach to decipher the effect of methyl jasmonate elicitation on the proteome of Silybum marianum L. hairy roots

Jasmonate and its methyl derivative, methyl jasmonate (MeJA), are naturally occurring compounds that mediate several plant physiological processes in response to pathogen attack, wounding, and ozone. Exogenous application of jasmonates triggers defense responses that resemble those initiated by pathogen infection and also modulates the production of certain secondary metabolites in a variety of plant species. In this study, we treated the hairy root cultures of Silybum marianum L. with 100 μM MeJA and then measured the content of Silymarin (SLM). We observed that the SLM content increased significantly after 48 h of MeJA treatment and remained constant for 120 h. However, MeJA treatment caused a significant growth reduction after 96 h incubation. The activity of lipoxygenase as a key enzyme in the jasmonate biosynthesis pathway and anti-oxidative enzymes; peroxidase and ascorbate peroxidase was also significantly increased after MeJA treatment. To elucidate the global effect of jasmonate on gene expression of S. marianum, we employed high resolution two-dimensional gel electrophoresis coupled with tandem mass spectrometry. Out of 670 reproducibly detected protein spots which were analyzed on each given gel, 32 spots were up- or down regulated upon MeJA treatment. Of them, ten proteins such as ER binding protein, glutamine synthetase, pathogenesis-related protein, caffeoyl CoA O-methyltransferase, and profilin-1 could be identified by mass spectrometry analysis. The possible implications of the identified proteins on physiological outcome of MeJA application in S. marianum hairy root culture will be discussed.

Fatty acid profile, oxidative stability and toxicological safety of bayberry kernel oil

The fatty acid profile, oxidative stability and toxicological safety of bayberry (Myrica rubra Sieb. et Zucc.) kernel oil (BKO) extracted by supercritical carbon dioxide (SC-CO₂) and solvent of diethyl ether were assessed. Fatty acid profile was determined by gas chromatography, oxidative stability by placing the sample of 25g in a blast oven at 50±1°C to accelerate oxidation and toxicological safety by bacterial reverse mutation (Ames test) and acute oral toxicity in mice. The results demonstrated that in comparison to lard and rapeseed oil, the peroxide values of BKO were higher but the acid values were similar during the incubation test. The Ames test demonstrated no mutagenicity and no obvious acute toxicity were observed, suggesting that the BKO has potential as a novel edible oil.

Total Serum Fatty Acid Analysis by GC-MS: Assay Validation and Serum Sample Stability

Analysis of n3 fatty acids in serum samples has clinical applications in supplementation trials, but the analysis can be challenging due to low levels, stability issues and intra-individual variation. This study presents the single laboratory validation of a gas chromatographic-mass spectral (GC-MS) assay for analysis of fatty acid methyl esters (FAME) using sensitive single ion monitoring and provides data on fatty acid stability under different sample handling conditions. Recovery of total fatty acids from serum with Folch extraction was optimized and parallelism tests with spiked samples indicated that the serum matrix did not interfere with mass spectral quantitation. Precision and accuracy of the assay at the lowest limit of quantitation and at low, medium and high levels met with accepted guidelines for single laboratory validation. Several storage conditions that can be encountered with clinical samples also were evaluated for impact on fatty acid levels in serum. Serum from blood that was stored refrigerated for 3 days yielded similar results as serum that was prepared and frozen at -80°C immediately. Serum storage at room temperature for 3-24 hours and serum subjected to one freeze/thaw cycle had minimal effects on fatty acid levels. The intra-individual variability in pregnant women was reasonably small, with significant correlation coefficients ranging from 0.35 to 0.76 for blood drawn between 12-20 weeks versus 34-36 weeks of gestation. These results indicate that GC-MS with single ion monitoring is valid for the analysis of total fatty acids in clinical samples, even when blood processing cannot be performed in a timely manner.

Exercise facilitates the action of dietary DHA on functional recovery after brain trauma

The abilities of docosahexaenoic acid (DHA) and exercise to counteract cognitive decay after traumatic brain injury (TBI) is getting increasing recognition; however, the possibility that these actions can be complementary remains just as an intriguing possibility. Here we have examined the likelihood that the combination of diet and exercise has the added potential to facilitate functional recovery following TBI. Rats received mild fluid percussion injury (mFPI) or sham injury and then were maintained on a diet high in DHA (1.2% DHA) with or without voluntary exercise for 12days. We found that FPI reduced DHA content in the brain, which was accompanied by increased levels of lipid peroxidation assessed using 4-hydroxy-2-hexenal (4-HHE). FPI reduced the enzymes acyl-CoA oxidase 1 (Acox1) and 17β-hydroxysteroid dehydrogenase type 4 (17β-HSD4), and the calcium-independent phospholipases A2 (iPLA2), which are involved in metabolism of membrane phospholipids. FPI reduced levels of syntaxin-3 (STX-3), involved in the action of membrane DHA on synaptic membrane expansion, and also reduced brain-derived neurotrophic factor (BDNF) signaling through its tyrosine kinase B (TrkB) receptor. These effects of FPI were optimally counteracted by the combination of DHA and exercise. Our results support the possibility that the complementary action of exercise is exerted on restoring membrane homeostasis after TBI, which is necessary for supporting synaptic plasticity and cognition. It is our contention that strategies that take advantage of the combined applications of diet and exercise may have additional effects to the injured brain.

Randomized placebo-controlled intervention with n-3 LC-PUFA-supplemented yoghurt: effects on circulating eicosanoids and cardiovascular risk factors

BACKGROUND & AIMS

The study examined the value of n-3 LC-PUFA-enriched yogurt as means of improving cardiovascular health.

DESIGN

Fifty three mildly hypertriacylglycerolemic subjects (TAG ≥ 1.7 mmol/L) participated in a randomized, placebo-controlled, double-blind, parallel designed study. The subjects consumed 1) control yoghurt; 2) yoghurt enriched with 0.8 g n-3 LC-PUFA/d; or 3) yoghurt enriched with 3 g n-3 LC-PUFA/d for a period of 10 wks. Blood samples were taken at the beginning and the end of the study period.

RESULTS

Following daily intake of 3 g n-3 LC-PUFA for 10 weeks, n-3 LC-PUFA levels increased significantly in plasma and red blood cells (RBC) with concomitant increase in the EPA-derived mediators (PGE₃, 12-, 15-, 18-HEPE) in plasma whilst cardiovascular risk factors such as HDL, TAG, AA/EPA ratio, and n-3 index were improved (P < 0.05); the decrease of TAG and increase in HDL were associated with the CD36 genotype.

CONCLUSION

The observed increase of n-3 LC-PUFA in RBC and plasma lipids due to intake of n-3 LC-PUFA enriched yoghurt resulted in a reduction of cardiovascular risk factors and inflammatory mediators showing that daily consumption of n-3 PUFA enriched yoghurt can be an effective way of supplementing the daily diet and improving cardiovascular health.

A monolithic lipase reactor for biodiesel production by transesterification of triacylglycerides into fatty acid methyl esters

An enzymatic reactor with lipase immobilized on a monolithic polymer support has been prepared and used to catalyze the transesterification of triacylglycerides into the fatty acid methyl esters commonly used for biodiesel. A design of experiments procedure was used to optimize the monolithic reactor with variables including control of the surface polarity of the monolith via variations in the length of the hydrocarbon chain in alkyl methacrylate monomer, time of grafting of 1-vinyl-4,4-dimethylazlactone used to activate the monolith, and time used for the immobilization of porcine lipase. Optimal conditions involved the use of a poly(stearyl methacrylate-co-ethylene dimethacrylate) monolith, grafted first with vinylazlactone, then treated with lipase for 2 h to carry out the immobilization of the enzyme. Best conditions for the transesterification of glyceryl tributyrate included a temperature of 37°C and a 10 min residence time of the substrate in the bioreactor. The reactor did not lose its activity even after pumping through it a solution of substrate equaling 1,000 reactor volumes. This enzymatic reactor was also used for the transesterification of triacylglycerides from soybean oil to fatty acid methyl esters thus demonstrating the ability of the reactor to produce biodiesel.