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Mixotrophic cultivation of Chlorella protothecoides was carried out in this study with an artificial light source. The culturing medium was supplemented with crude glycerol by-product from a biodiesel facility as an organic carbon source, and the spent yeast from a local brewery was used as an organic nitrogen source. Experiments were performed based on a 3×3 factorial design, with algal biomass (g/L) as the response. Data was fitted into a response surface model to investigate the impact on biomass of 3 factors: light intensity, carbon concentration and nitrogen concentration. According to the model, a maximal biomass of 20.94 g/L could be reached at a light intensity of 100 µmol m− 2s− 1, carbon concentration of 24.1 g/L and nitrogen concentration of 0.7 g/L.

Pretreatments are often needed for lignocellulosic biomass feedstocks before either thermochemical or biochemical conversion processes. Our previous research has demonstrated the potential of bioleaching, with its superior capability of removing certain inorganic compounds compared to water leaching, to improve biomass quality for thermochemical conversion in biofuel production. In this study, the bioleaching process was scaled up from 250 mL beakers to be carried out in custom-designed 2.5 L bioreactors. The fungus Aspergillus niger was used in the bioreactors for leaching sorghum straw biomass with an initial ash content of 6.0%. The effects of three operating parameters on leaching efficiency (i.e., residual ash content) were extensively studied, including the fungal mass added to each reactor, leaching time, and glucose concentration in the starting liquid phase. Response surface methodology (RSM) was used for the experiment design. The results showed that the average residual ash content of the sorghum feedstock after bioleaching was significantly lower (3.63 ± 0.19%) than that of the ash content (4.72 ± 0.13%) after water leaching (p < 0.00001). Among the three parameters, glucose concentration in the starting liquid phase had the most significant effect on leaching effectiveness (p = 0.0079). Based on this outcome, subsequent bioleaching experiments yielded reductions in residual ash content to as low as 2.73%.

Agricultural residues and energy crops often contain high contents of alkali metals, chlorine, silica, and other elements that promote slagging, fouling, corrosion, and gas emission during thermochemical conversion (e.g., combustion and gasification). Water leaching is a common method, but not always effective to reduce such elements. Bioleaching by adding microbes to water leaching was introduced to leach cellulosic biomass in this study. Three microbial species including two fungi (Fusarium oxysporum and Aspergillus niger) and one bacterium (Burkholderia fungorum) were selected to leach four lignocellulosic feedstocks such as corn stover, wheat straw, switchgrass, and sorghum. Among three microbes, A. niger was found the most efficient to remove most elements by 80% in 48 h, and sorghum was relatively more amenable to bioleaching. With A. niger, the bioleaching with water to feedstock (w/w) ratio of 25 for 6 h was sufficient to leach K (85%), Cl (90%), Mg (60%), and P (70%) from sorghum. Overall, bioleaching is more efficient than water leaching except for Na. Studies on bioleaching mechanism indicated that the acidification resulted from organic acids produced by A. niger during bioleaching might contribute to the higher leaching efficiency over other microbial species and water leaching.

Eversa Transform was used as an enzymatic catalyst to transform glandless and crude (heavy pigment) cottonseed oils into biodiesel. The oils were reacted with methanol at a 6:1 molar ratio with modified amounts of water, lipase, and temperature. Reactions were conducted in the presence of lipase and water at doses of 2, 5, and 8 wt% and 1, 3, and 6 wt%, respectively. Product composition and conversion were determined using the gas chromatography method of ASTM D6584. Oxidative stability was determined following EN 15751. The conversion to fatty acid methyl esters averaged 98.5% across all samples. Temperature had the most significant effect on conversion (p < 0.0035). Lipase and water dosages did not affect conversion, while each had an effect with temperature that was significant across the difference between 3 and 1 wt% water content and between 8 and 5 wt% enzyme content between the two temperatures (p = 0.0018 and 0.0153), respectively. Induction periods (oxidative stability) of the glandless and crude cottonseed oils were significantly different, but there was no difference between the two oil conversions based on oil type. Keywords: Biodiesel, Cottonseed oil, Fatty acid methyl esters, Lipase, Oxidative stability, Transesterification.

Biodiesel from waste cooking oil (WCO) requires antioxidants to meet oxidation stability specifications set forth in ASTM D6751 or EN 14214. In contrast, unrefined cottonseed oil (CSO), containing tocopherols and gossypol, produces biodiesel of higher oxidation stability. However, only a portion of these CSO endogenous antioxidants are suspected to be retained in biodiesel. Because the economics of biodiesel manufacturing rely upon inexpensive sources of triglycerides, emphasis was placed on developing improved alternative processing methods where WCO was the main source of methyl esters (WCOME) and CSO was used as a supplemental source of triglycerides and antioxidants in a 4:1 ratio. This study compared four processing methods for their ability to produce biodiesel of increased oxidative stability prepared from a 4:1 ratio of WCO:CSO. Two novel processing methods developed for this study utilise solvent properties of fatty acid methyl esters and glycerol to avoid additional chemical inventory fo...

Microalga is a promising feedstock for biofuel, chemical, food, and animal feed; however, harvesting is a critical barrier for its commercial application. This communication demonstrates a new harvesting technology by utilizing the phase separation of thermoresponsive polymers and charged copolymers of N-isopropylacrylamide and allylamine. Chlorella protothecoides cells are separated from solution when the mixture of algae and polymers is heated above the lower critical solution temperature of polymers (~ 32 °C), where the polymer phase separates from the aqueous media and aggregates into a solid–gel phase. It was found that copolymer concentration, allylamine content (mol%) and charge (based on initial solution pH) affect the extent of polymer phase separation and alga separation efficiency. The copolymer containing allylamine with lower than 2.6 mol% displayed nearly complete algal cell separation at polymer concentrations of 25–50 mg/mL and pH 7. The results indicated that thermoresponsive polymers provide a promising technology for alga harvesting using recyclable and reusable materials.

Biomass and lipid accumulation of heterotrophic microalgae Chlorella protothecoides by supplying mixed waste substrate of brewer fermentation and crude glycerol were investigated. The biomass concentrations of the old and the new C. protothecoides strains on day 6 reached 14.07 and 12.73 g/L, respectively, which were comparable to those in basal medium with supplement of glucose and yeast extract (BM-GY) (14.47 g/L for old strains and 11.43 g/L for new strains) (P > 0.05). Approximately 81.5% of total organic carbon and 65.1% of total nitrogen in the mixed waste were effectively removed. The accumulated lipid productivities of the old and the new C. protothecoides strains in BM-GY were 2.07 and 1.61 g/L/day, respectively, whereas in the mixed waste, lipid productivities could reach 2.12 and 1.81 g/L/day, respectively. Our result highlights a new approach of mixing carbon-rich and nitrogen-rich wastes as economical and practical alternative substrates for biofuel production.

An integrated process has been proposed for a sweet sorghum biorefinery in which all carbohydrate components of the feedstock were used for production of fuel ethanol and industrial chemicals. In the first step, the juice was extracted from the stalks. The resultant bagasse was then pretreated using the soaking in aqueous ammonia (SAA) process, which did not result in significant loss of cellulose and hemicellulose, to enhance subsequent enzyme hydrolysis for production of fermentable sugars. Following pretreatment, the bagasse was hydrolyzed with a commercial enzyme product containing high hemicellulase activity (Accellerase XY). The xylose-rich solution obtained after solid/liquid separation was used for production of value-added co-products using suitable microorganisms. The value-added co-products produced to demonstrate the feasibility were astaxanthin and D-ribose. The residual solids were then hydrolyzed with a commercial enzyme product containing high cellulase activity (Accellerase 1500), with the juice extracted in the first step used as make-up water. By combining the sugar in the juice with the glucose released from the residual solids by enzyme hydrolysis, high ethanol concentrations could be achieved, which resulted in lower distillation cost than if pure water were used for enzyme hydrolysis and subsequent fermentation, as normally performed in cellulosic ethanol production.

Transesterification of refined cottonseed oil (CSO) was carried out with methanol, ethanol, 1-butanol, and various mixtures of these alcohols to produce biodiesel. In the mixed alcohol transesterifications, formation of methyl esters was favored over ethyl and butyl esters. The influence of ester head group on fuel properties was determined. Specifically, cold flow properties, lubricity, and energy content improved in the order: CSO butyl esters (CSBE, best) > ethyl esters (CSEE) > methyl esters (CSME). Higher kinematic viscosities (KVs) as well as lower iodine values (IVs) and wear scars were observed with larger ester head groups. Blends of CSME, CSEE and CSBE exhibited properties intermediate to the neat esters. All ester samples were within the limits prescribed in ASTM D6751 and EN 14214 for cetane number, acid value (AV), glycerol (free and total) content, sulfur, and phosphorous. Also examined was the influence of blending alkyl esters with petrodiesel. All blends exhibited improved cold flow properties versus unblended alkyl esters. Enhanced lubricity was observed after blending. With increasing content of biodiesel, higher KVs and lower energy contents were observed. Finally, all blends were within the limits specified in ASTM D975 and D7467 for AV, KV and sulfur.

Biodiesel, defined as mono-alkyl esters of long-chain fatty acids derived from vegetable oils or animal fats, is an attractive renewable fuel alternative to conventional petroleum diesel fuel. Biodiesel produced from oils such as cottonseed oil and poultry fats suffer from extremely poor cold flow properties because of their high saturated fatty acid content. In the current study, Ethyl Levulinate (ethyl 4-oxopentanoate) was investigated as a novel, bio-based cold flow improver for use in biodiesel fuels. The cloud (CP), pour (PP), and cold filter plugging points (CFPP) of biodiesel fuels prepared from cottonseed oil and poultry fat were improved upon addition of ethyl levulinate at 2.5, 5.0, 10.0, and 20.0% (vol). Reductions of 4–5 °C in CP, 3–4 °C in PP and 3 °C in CFPP were observed at 20 vol % ethyl levulinate. The influence of ethyl levulinate on acid value, induction period, kinematic viscosity and flash point was determined. The kinematic viscosities and flash points decreased with increasing content of ethyl levulinate. All samples (≤15 vol % ethyl levulinate) satisfied the ASTM D6751 limit with respect to flash point, but none of the 20 vol % blends were acceptable when compared to the higher EN 14214 specification. Acid value and oxidative stability were essentially unchanged upon addition of ethyl levulinate. In summary, ethyl levulinate appears acceptable as a diluent for biodiesel fuels with high saturated fatty acid content.

The low temperature operability, kinematic viscosity, and acid value of poultry fat methyl esters were improved with addition of ethanol, isopropanol, and butanol with increasing alcohol content. The flash point decreased and moisture content increased upon addition of alcohols to poultry fat methyl esters. The alcohol type did not result in a statistically significant difference in low temperature performance at similar blend ratios in poultry fat methyl esters. In addition, blends of ethanol in poultry fat methyl esters afforded the least viscous mixtures, whereas isopropanol and butanol blends were progressively more viscous, but still within specifications contained in ASTM D6751 and EN 14214. Blends of alcohols in poultry fat methyl esters resulted in failure of the flash point specifications found in ASTM D6751 and EN 14214. Flash points of butanol blends were superior to those of isopropanol and ethanol blends, with the 5 vol.% butanol blend exhibiting a flash point (57 °C) superior to that of No. 2 diesel fuel (52 °C). Blends of alcohols in poultry fat methyl esters resulted in an improvement in acid value with increasing content of alcohol. An increase in moisture content of biodiesel was observed with increasing alcohol content, with the effect being more pronounced in ethanol blends versus isopropanol and butanol blends. Finally, none of the alcohol–methyl ester samples exhibited a phase separation at sub-ambient temperatures.

The low temperature operability and oxidative stability of cottonseed oil methyl esters (CSME) were improved with four anti-gel additives as well as one antioxidant additive, gossypol. Low temperature operability and oxidative stability of CSME was determined by cloud point (CP), pour point (PP), cold filter plugging point (CFPP), and oxidative stability index (OSI). The most significant reductions in CP, PP, and CFPP in all cases were obtained with Technol ® , with the average reduction in temperature found to be 3.9 °C. Gunk ® , Heet ® , and Howe's" were progressively less effective, as indicated by average reductions in temperature of 3.4, 3.0, and 2.8 °C, respectively. In all cases, the magnitude of CFPP reduction was greater than for PP and especially CP. Addition of gossypol, a polyphenolic aldehyde, resulted in linear improvement in OSI (R 2 = 0.9804). The OSI of CSME increased from 5.0 to 8.3 h with gossypol at a concentration of 1000 ppm.

Kinetic analysis was investigated for a carbon- limited medium (C/N ratio = 5.0) supporting the growth of the 5,8,11,14,17-eicosapentaenoic acid (20:5; x-3) (EPA)- accumulating fungal organism Pythium irregulare. The productivity and yield parameters at three temperatures, 14, 21, and 28C, demonstrated growth-coupled synthesis for lipid-free biomass growth and lipid accumulation. For this system, the maximum specific growth rate and theoretical maximum biomass yield based on logistic growth kinetics were used to determine an activation energy of the growth process, Eg, of 36.5 kJ mol -1 . At 14, 21, and 28C, peak lipid yield occurred after culturing for 7, 4, and 3 days, respectively, with peak lipid yields of 8.14, 12.8, and 6.69 g lipid 100 g -1 glucose. At these peak yields, the maximum lipid-free biomass productivity was achieved at the colder 14C temperature as well as an increased con- centration of EPA—10.9 wt%. Despite these enhance- ments, the maximum relative lipid production (PR(FA/B)) was achieved at 21C—19.1%.

Canola oil was transesterified using a 1 : 1 molar mixture of methanol and ethanol (M/E) with potassium hydroxide (KOH) catalyst. The effects of catalyst concentration (0.5–1.5 wt-%), molar ratio of M/E to canola oil (3 : 1 to 20 : 1) and reaction temperature (25–75 7C) on the percentage yield measured after 2.5 and 5.0 min were optimized using a central composite design. A maximum percentage yield of 98% was obtained for a catalyst concentration of 1.1 wt-% and an M/E to canola oil molar ratio of 20 : 1 at 25 7 Ca t 2.5 min, whereas a maximum percentage yield of 99% was obtained for a catalyst concentration of 1.15 wt-% and all molar ratios of reactants at 25 7C at 5 min. Statistical analysis demonstrated that increasing catalyst concentration and molar ratio of reactants resulted in curvilinear and linear trends in percentage yield, both at 2.5 and 5 min. However, reaction temperature, which affected the percentage yield at 2.5 min linearly, was insignificant at 5 min. The resultant mixed methyl/ethyl canola esters exhibited enhanced low-temperature performance and lubricity properties in comparison to neat canola oil methyl esters and also satisfied ASTM D6751 and EN 14214 standards with respect to oxidation stability, kinematic viscosity, and acid value.

Canola materials including processed flake and cake were investigated as both of carbon and nitrogen sources for the production of new oil containing polyunsaturated fatty acids (PUFAs). With conversion of the fungi Mortierella alpina , modified lipids enhanced the oil profile with the addition of three PUFAs, γ-linolenic acid (GLA, γ-C18:3n6), arachidonic acid (ARA, C20:4n6) and eicosapentaenoic acid (EPA, C20:5n3). The ratio of polyunsaturated to saturated fatty acid (P/S) increased 50% compared to the original canola oil. ARA yield of 20.3 mg/g flake was comparable to 20.1 mg/g glucose, and higher than 12.5 mg/g cake. EPA yield of 3.3 mg/g flake was greater than 2.7 mg/g cake, and much greater than 0.3 mg/g glucose. The mixed culture of two strains, M. alpina and Pythium irregulare , resulted in higher production of ARA and EPA than their single cultures. Mixed culture achieved ARA yields of 26 mg/g flake, 23 mg/g cake and 38 mg/g glucose, and had favorable lipid profiles with P/S of 6.5 and 8.7 for growth on flake and cake, respectively. In addition, a method was developed to estimate the bioconversion rate from digested canola oil to fungal oil, which was nearly 50% when canola flake and cake were utilized as substrate.

The change of pressure, temperature and phase during high-pressure carbon dioxide explosion process were investigated. Different initial temperature and pressure conditions were chosen, ranging from 25 to 65 °C and 500 to 3000 psi covering initial liquid, supercritical and gas phases. Under certain initial conditions with low temperature and high pressure, the depressurization process caused a phase change that increased the release time where the depressurization–time curves did not exponentially decrease. This explosion process was characterized based on total release time, rate of depressurization, and effect of phase change on the rate of depressurization. The temperature change associated with the change of pressure was also discussed. Canola flakes were exploded using chosen initial conditions. Oil extraction from canola flakes using supercritical carbon dioxide was improved after explosion treatment. Explosion at 35 °C and 3000 psi of initial condition resulted in the highest oil yield.

Transesterification of cottonseed oil was carried out using ethanol and potassium hydroxide (KOH). A central composite design with six center and six axial points was used to study the effect of catalyst concentration, molar ratio of ethanol to cottonseed oil and reaction temperature for percentage yield (% yield) and percentage initial absorbance (%A385nm) of the biodiesel. Catalyst concentration and molar ratio of ethanol to cottonseed oil were the most significant variables affecting percentage conversion and %A385nm. Maximum predicted % yield of 98% was obtained at a catalyst concentration of 1.07% (wt/wt) and ethanol to cottonseed oil molar ratio of 20:1 at reaction temperature of 25 °C. Maximum predicted %A385nm of more than 80% was obtained at 0.5% (wt/wt) catalyst concentration and molar ratio of 3:1 at 25 °C. The response surfaces that described % yield and %A385nm were inversely related. Gossypol concentration (% wt), oxidative stability and %A385nm of biodiesel were found to be highly correlated with each other. Hence, color %A385nm is a measure of the amount of pigments present in biodiesel fuels that have not yet been subjected to autoxidation. High gossypol concentration also corresponds to a fuel with high oxidative stability. The fatty acid ethyl esters (FAEE) produced from cottonseed oil had superior oxidative stability to fatty acid methyl esters (FAME) produced from cottonseed oil.

Cocodrie is a long grain rice variety commonly grown throughout the southern United States. Initial industrial scale production of this variety was largely successful, but rice harvested late in the season exhibited lower than expected yield and quality. A pilot scale rice mill was used to determine if rice milling processing parameters could be manipulated to optimize the yield and quality of early and late season Cocodrie rice. A response surface methodology was used to determine rice mill settings of roll gap (husking), feed volume — also known as flow rate — (milling), and water velocity (polishing) to achieve maximal processing outputs including yield, transparency, whiteness, wholeness, and degree of milling. Results showed that milling flow rate significantly affected whiteness and milling degree for early season Cocodrie, and whiteness, milling degree, and wholeness for late season Cocodrie. Roll gap and water velocity did not significantly affect output processing parameters. Though milling quality parameters for late season rice were lower than early season rice, optimal yields and wholeness for both batches were similar. Ridge analysis indicated that machine settings could be manipulated to optimize specific output parameters for early and late season batches of rice. A score variable was developed to determine a unique set of optimal milling settings for each batch based on the relative importance of each of the five parameters. The research presented in this work is intended to be useful to rice processors working with the Cocodrie variety and is presented in terms of optimization.

Ohmic heating has been shown to increase the extraction yields of sucrose from sugar beets, apple juice from apples, beet dye from beet root, and soymilk from soybeans. Rice bran is a byproduct of the rice milling process that has economic potential by virtue of highly nutritious rice bran oil contained within the bran. In this study, ohmic heating was used to stabilize rice bran and to improve rice bran oil extraction yield as compared to microwave heating and a control (no heating). Results showed that ohmic heating is an effective method for rice bran stabilization with moisture addition. Free fatty acid concentration increased more slowly than the control for raw bran samples subjected to ohmic heating with no corresponding temperature rise, indicating that electricity has a non-thermal effect on lipase activity. Ohmic heating increased the total percent of lipids extracted from rice bran to a maximum of 92%, while 53% of total lipids were extracted from the control samples. Lowering the frequency of alternating current significantly increased the amount of oil extracted, probably due to electroporation. Ohmic heating was successfully applied to rice bran despite its high oil content. This could have important implications for the enhanced extraction of non-polar constituents.

Lipids that contain polyunsaturated fatty acids (PUFA) have therapeutic value. PUFA, however, degrade in high-temperature, oxygen-rich conditions typical of conventional hot solvent-extraction and distillation methods. Supercritical CO2 extraction was chosen as an alternative method to recover these valuable compounds from the lower fungus, Pythium irregulare. Freeze-dried biomass was subjected to an aqueous phase and placed into a flow-through extraction apparatus. Extraction of oil from this biomass showed some success for moisture contents as high as 30% (wet basis). The addition of a novel CO2-philic surfactant to the wet biomass with moisture contents as high as 95% (wet basis) increased the extraction rate of fungal oil by more than an order of magnitude. For tests with extraction times of 5 to 6 h, data for the diffusion-controlled region were modeled with an analytical solution to Fick’s second law. Equilibrium data were also obtained for the fungal oil at two isotherms (40 and 60°C) over a pressure range of 13.7 to 27.5 MPa.

A series of polyunsaturated fatty acids (PUFAs), including 5,8,11,14,17-cis-eicosapentaenoic acid (EPA) and 5,8,11,14-cis-arachidonic acid (ARA), have widespread nutritional and pharmaceutical value. This study investigated the potential production of the two economically important fatty acids with a fungal fermentation process. The substrates for the fungal fermentation process were crude soybean oil (SBO), a sucrose waste stream (SWS) and a soymeal waste stream (SMW). Glucose (GLU) was used as a substrate in control groups. The microorganisms used were Mortierella elongata NRRL 5513 and Pythium irregulare ATCC 10951. The use of P. irregulare ATCC 10951 is preferred since it produced high levels and reasonable ratios of EPA and ARA at various temperatures (12, 18 and 24°C). An advantage of P. irregulare was its ability to produce EPA at room temperature, which is desirable for commercial applications. Soybean oil had a unique characteristic of stabilizing pH; the optimal initial pH was 6.0. An emulsifier, Tween 80, allowed much greater dispersion of the SBO in aqueous broth and helped increase EPA and ARA production. In experiments exploring the combination effects of sugars (1, 2 and 3%) with soybean oil (4%) and Tween 80 (0.2%) at 12, 18 and 24°C, EPA yields of SMW + SBO were significantly higher than those of GLU + SBO and SWS + SBO. The greatest EPA production (1400 mg/l) was obtained at 12°C (1% SMW, 4% SBO). Cultivation of P. irregulare at reduced temperatures increased lipid unsaturation. The highest ARA level appeared at 18°C − SMW + SBO (2000 mg/l), which was a statistically interactive temperature-media combination. The ARA/EPA ratio in this study ranged from 0.2 to 4.0, which would be reasonable for food additive or supplement applications, e.g infant formula.

The feasibility of saving energy by recirculating drying air in batch dehydrators was tested. Peaches and apples received treatments of four constant recirculation rates (0, 25, 50, and 75%). The total energy use for drying was reduced by 53% when drying peaches and 46% when drying apples with 75% recirculated air. Total drying times were almost the same for all recirculation rates. The results also suggested that even higher fixed recirculation rates could further optimize the drying system for greater energy savings.

Lipids obtained from Chlorella protothecoides in heterotrophic cultivation are considered a suitable feedstock for biodiesel production. In this study, glucose fed-batch fermentation was performed to increase final biomass and lipid production. The biomass productivity and lipid productivity were 6.28 and 2.06 g/L day, respectively. Biomass/glucose conversion and the lipid/glucose conversion were 43.3% and 14.2%, respectively. Extraction of lipids from algae has been identified as a key bottleneck in bioprocessing operations. Supercritical carbon dioxide (SC-CO 2 ) was applied for neutral lipids extraction and the SC-CO 2 kinetics was investigated by the Goto et al. model. The modeling showed a good fit with experimental data. Additionally, neutral lipids extracted by SC-CO 2 displayed a suitable fatty acid profile for biodiesel [mainly C18:1 (60.0%), C18:2 (18.7%) and C16:0 (11.5%)]. Our study demonstrated the ability to produce high levels of neutral lipids through heterotrophic algal culture and subsequent extraction of lipids with SC-CO 2 method developed.

Accumulating evidence in both humans and animal models indicates that dietary intake of long-chain polyunsaturated fatty acids (PUFAs) can improve response to chemotherapy. The intent of this study was to determine the mechanisms by which PUFAs affect the response to anticancer chemotherapy.Human colorectal cancer cell line Caco-2 was used as a model system in this study. Caco-2 cells were treated with different concentrations of three PUFAs: eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (AA). Real-time polymerase chain reaction was used to determine mdr1 gene (codes for P-glycoprotein [P-gp]) expression. Western blotting and calcein-acetoxymethylester efflux assay were used for P-gp expression and functional evaluation, respectively. Furthermore, apoptosis assay was conducted by adding PUFAs with paclitaxel to confirm the synergetic effect. Finally, gene expression of nuclear receptors CAR and PXR were estimated to evaluate the possible mechanisms.Both classes of PUFAs, omega-3 (ω-3) and omega-6 (ω-6), can cause a modest but very reproducible reduction of gene expression, protein production, and pump activity of MDR1. Incubation of cells with PUFAs greatly enhanced the cytotoxicity of the anticancer drug paclitaxel, manifested mainly through enhanced paclitaxel-induced apoptosis. Furthermore, PUFAs increased the messenger RNA (mRNA) levels of the nuclear receptors CAR and PXR, thus implicating these two transcription factors as cellular targets of PUFAs in cells but not directly affecting MDR1 regulation.Our results suggest that inhibition of the multidrug resistance MDR1/P-gp is one mechanism through which dietary polyunsaturated fatty acids exert a synergetic effect on the response of tumor cells to anticancer drugs.

Microalgal lipids may be a more sustainable biodiesel feedstock than crop oils. We have investigated the potential for using the crude glycerol as a carbon substrate. In batch mode, the biomass and lipid concentration of Chlorella protothecoides cultivated in a crude glycerol medium were, respectively, 23.5 and 14.6 g/l in a 6-day cultivation. In the fed-batch mode, the biomass and lipid concentration improved to 45.2 and 24.6 g/l after 8.2 days of cultivation, respectively. The maximum lipid productivity of 3 g/l day in the fed-batch mode was higher than that produced by batch cultivation. This work demonstrates the feasibility of crude biodiesel glycerol as an alternative carbon substrate to glucose for microalgal cultivation and a cost reduction of carbon substrate feed in microalgal lipid production may be expected.

Canola flake was investigated as a potential substrate for fungal conversion to produce polyunsaturated fatty acids (PUFAs)-added oil in a 7 l fermenter. The results showed that yields of total oil were reduced 9–22% compared to initial oil in the canola flake, but as high as 445 mg/l arachidonic acid (ARA, C20:4n6) and 67 mg/l eicosapentaenoic acid (EPA, C20:5n3) were produced. The percentages of ARA and EPA of total fatty acids in this fermented oil were 15.5% and 2.3%, respectively. Supercritical CO2 extraction was then investigated for the lipid recovery from fermented canola flake, and extraction kinetics were modeled. The feasibility was demonstrated for production of PUFAs in a laboratory-scale fermentor using canola flake as a single nutrient, and for lipid extraction using supercritical CO2.

Publisher Summary Supercritical Fluid Extraction (SFE) with carbon dioxide is established as a process for the decaffeination of coffee beans and tea. Recent studies have focused on other applications, especially with botanical materials and thermally liable substances. The development of new separation techniques for pharmaceutical and food industries has received a lot of attention due to rising concerns about health, environmental, and safety hazards associated with traditional solvent techniques. SFE with CO 2 is used in the extraction of desired components from natural materials for eventual use in food, perfumery, pharmaceutical, and nutraceutical industries. SFE utilizes the ability of normally gaseous chemicals to become excellent solvents for certain solutes under a combination of tunable properties in terms of temperature and pressure. The increasing public awareness about healthy, natural, and non-toxic products and strict environmental regulations has acted as an impetus for the supercritical fluid industry.

Rice bran oil is one of the healthiest edible oils due to higher levels of antioxidants, which have beneficial health effects. Extraction procedures significantly affect the concentration of the antioxidants and yield of lipids from bran. Compared to conventional solvent extraction, environmentally friendly supercritical fluid extraction (SFE) procedures are gaining increased acceptance for extraction of nutraceutical compounds from biological materials. Rice husk ash obtained after burning of husk in the energy generation system exhibit absorbent properties for lipid components such as free fatty acids, phospholipids, lutein etc. In the present study three different extraction methods (1) Soxhlet extraction with petroleum ether (2) SFE (3) SFE coupled with adsorption on rice hull ash; were investigated for their effect on level of antioxidants in the rice bran oil and oil yield. In soxhlet extraction time of extraction was varied from 6 to 10 hrs. During SFE extraction pressure (6000 and 8000 psi) and flow rate (45 and 65 g/min) of carbon dioxide were varied where as temperature was kept constant at 40 oC. Antioxidants level was higher with SFE extractions, where as oil yield was higher with soxhlet extraction. Pressure increase improved concentrations of antioxidants in SFE extractions where as flow was not having significant influence on it. Oil yield increased with both pressure and flow. Hull ash was having mixed effect on antioxidant concentrations. Further experiments are in progress at other extraction conditions.