Conversion Of Lipids Research Articles

Lipid conversion of Scenedesmus rubescens biomass into biodiesel using biochar catalysts from malt spent rootlets

AbstractBACKGROUNDMicroalgae are considered a third–generation raw material for biofuel production. This work compared the conversion of the extracted oil from the freshwater microalgae Scenedesmus rubescens via transesterification for the production of biodiesel. Considering the cost of biodiesel production, heterogeneous catalysts present a significant advantage because of their stability and reusability. Biochar and modified biochar with H2SO4 were used as catalysts.RESULTSBiochar (BC) was pyrolyzed at 850 °C, under limited oxygen conditions, and was activated by sulphuric acid (H–BC). The catalyst: oil mass ratios tested were from 0 to 0.7:1 for BC, and from 0 to 1:1 for H–BC. The biochar sample exhibited a strong buffer capacity in the pH range between 7 and 5.5, while the acid treated biochar was strongly acidic and could neutralize a significant amount of bases. The produced methyl esters are almost the same in all cases examined. BC samples gave better transesterification results, as far as it concerns the conversion, compared to H–BC.CONCLUSIONThe enhanced activity of the BC with mass used may be correlated with the basic minerals presented on the biochar surface. Raw biochar gave better conversion results (47%) during transesterification compared to the modified biochar with H2SO4 (24%) with better catalyst to molar ratio, 0.7:1 and 0.1:1, respectively. © 2020 Society of Chemical Industry

Evolution of the microstructure and the drug release upon annealing the drug loaded lipid-surfactant microspheres

The present study investigates the drug release-governing microstructural properties of melt spray congealed microspheres encapsulating the drug crystals in the matrix of glyceryl behenate and poloxamer (pore former). The solid-state, morphology, and micromeritics of the microspheres were characterized, before and after annealing, using calorimetry, X-ray scattering, porosimetry, scanning electron microscopy, and, NMR diffusometry. The in vitro drug release from and water uptake by the microspheres were obtained. The extent and the rate of drug release from the microspheres increased with a high poloxamer content and at higher annealing temperature and RH. All the drug release profiles were describable using the Higuchi release kinetics pointing towards the diffusion controlled release, both before and after annealing. The annealing process led to the polymorphic conversion of lipid and the increase in the pore size, predominantly at a higher temperature and humidity and for a high poloxamer content. The poloxamer domain increased from an initial 300 nm, up to 2000 nm upon annealing. The water diffusion rate inside the annealed microsphere was twice as fast as for unannealed counterparts. The findings relate the overall phase and pore structure change of the microsphere to the increased drug release induced by annealing. This work serves as a basis for the rational understanding of the modification of the in vitro performance by annealing, a widely used post-process for solid lipid products.

Comparative transcriptomics reveals candidate carotenoid color genes in an East African cichlid fish

BackgroundCarotenoids contribute significantly to animal body coloration, including the spectacular color pattern diversity among fishes. Fish, as other animals, derive carotenoids from their diet. Following uptake, transport and metabolic conversion, carotenoids allocated to body coloration are deposited in the chromatophore cells of the integument. The genes involved in these processes are largely unknown. Using RNA-Sequencing, we tested for differential gene expression between carotenoid-colored and white skin regions of a cichlid fish, Tropheus duboisi “Maswa”, to identify genes associated with carotenoid-based integumentary coloration. To control for positional gene expression differences that were independent of the presence/absence of carotenoid coloration, we conducted the same analyses in a closely related population, in which both body regions are white.ResultsA larger number of genes (n = 50) showed higher expression in the yellow compared to the white skin tissue than vice versa (n = 9). Of particular interest was the elevated expression level of bco2a in the white skin samples, as the enzyme encoded by this gene catalyzes the cleavage of carotenoids into colorless derivatives. The set of genes with higher expression levels in the yellow region included genes involved in xanthophore formation (e.g., pax7 and sox10), intracellular pigment mobilization (e.g., tubb, vim, kif5b), as well as uptake (e.g., scarb1) and storage (e.g., plin6) of carotenoids, and metabolic conversion of lipids and retinoids (e.g., dgat2, pnpla2, akr1b1, dhrs). Triglyceride concentrations were similar in the yellow and white skin regions. Extracts of integumentary carotenoids contained zeaxanthin, lutein and beta-cryptoxanthin as well as unidentified carotenoid structures.ConclusionOur results suggest a role of carotenoid cleavage by Bco2 in fish integumentary coloration, analogous to previous findings in birds. The elevated expression of genes in carotenoid-rich skin regions with functions in retinol and lipid metabolism supports hypotheses concerning analogies and shared mechanisms between these metabolic pathways. Overlaps in the sets of differentially expressed genes (including dgat2, bscl2, faxdc2 and retsatl) between the present study and previous, comparable studies in other fish species provide useful hints to potential carotenoid color candidate genes.

The Lipid Composition of Platelets and the Impact of Storage: An Overview.

Lipids and bioactive lipid mediators are essential for platelet function. The lipid profile of platelets is highly dynamic due to free exchange of lipids with the plasma, release of extracellular vesicles, and both enzymatic and nonenzymatic lipid conversion. The lipidome of platelets changes in response to activation to accommodate the functional requirements of platelets, particularly for maintenance of hemostasis. Furthermore, when stored at room temperature as a component for transfusion, the lipid profile of platelets is altered. Although there is a growing interest in alternate storage conditions, such as refrigeration and cryopreservation, few contemporary studies have examined the impact of these storage modes on the lipid profile. However, evidence exists that bioactive lipid mediators produced over the storage of blood products may have functional implications once these products are transfused. As such, there is a need to determine the changes occurring to the lipid profile of these products over storage. This review outlines the role of lipids in platelets and discusses the current state of lipidomics for studying platelet components for transfusion in an effort to highlight the necessity for additional transfusion-focused investigations.

Bio-oil production from residual biomass of microalgae after lipid extraction: The case of Dunaliella Sp

Abstract Microalgae are known as the potential feedstock for production of bio based fuels due to their high lipid contents. Residual microalgae biomass after conversion of lipids into biodiesel can be converted into bio-oils in order to achieve complete exploitation of microalgae biomass in a microalgae biorefinery. Hydrothermal liquefaction (HTL) is a promising way for converting high-moisture biomass waste into high-energy crude oil. Therefore, this study intended to produce bio–oil from residual biomass of microalgae Dunaliella Sp. after lipid extraction by utilizing HTL as a biorefinery concept. HTL results showed that the average bio-oil yield was 11.81 w/w%, which was obtained at 350 °C, a residence time of 60 min and pressure of 200 bar. The results of CHNS analysis showed that crude oil produced by the HTL process in this study contains 4.82% nitrogen, 68.53% carbon, 1% hydrogen, 21.9% sulfur, which are within the permitted ranges.

Conversion of lipid into high-viscosity branched bio-lubricant base oil

To produce high-quality bio-lubricant, we reported a novel approach using lipids as a raw material, the process involved selective hydrogenation to fatty alcohols, dehydration of fatty alcohols to α-olefins, coupled polymerization–hydrogenation reactions.

Incorporation of Biosolids as Water Replacement in a Two-Step Renewable Hydrocarbon Process: Hydrolysis of Brown Grease with Biosolids

The accumulating volumes of biosolids in lagoons worldwide have intensified the need to develop innovative wastewater treatment strategies. Here, we provide proof-of-concept for the incorporation of biosolids into the hydrolysis step of a two-step thermal conversion of lipids for production of renewable hydrocarbons, which can be utilized as renewable fuels. Brown grease was hydrolysed with biosolids or water at 260–280 °C for 60 min at a mass ratio of 1:1 feed to water or biosolids. The feedstock and products were characterized using various analytical techniques to compare the performance of biosolids to water. The results indicated that there was no significant difference in the degree of hydrolysis of brown grease when biosolids was used as water replacement. The fatty acids composition after hydrolysis when biosolids was used as a water replacement also remained largely unchanged. Hydrolysis of brown grease with biosolids could be achieved at pH ranging from 3.3 to 8.9, and at a lower than previously established temperature. Significantly, the rapid settling of solid material in biosolids observed after thermal hydrolysis of brown grease may reduce the necessity of biosolids settling lagoons. Thus, incorporation of biosolids into a lipid hydrolysis-pyrolysis process may simultaneously benefit the biofuel and waste management sectors.Graphic

Direct Lewis-Brønsted acid ethanolysis of sewage sludge for production of liquid fuels

Ethanolysis carried out under Lewis-Brønsted acid catalysis was investigated as a possible process to valorize the organic fraction of urban sewage sludge, with the aim of selectively obtaining liquid biofuels. In a single reactive step, the conversion of lipids into fatty acid ethyl esters, of carbohydrates into ethyl levulinate, furanic compounds and ethyl glycosides and of proteins into ethyl ester of amino acids was achieved. The optimization of reactive conditions was conducted using pure chemicals as model compounds. The effect of the co-presence of water was also considered. Then, real samples of sewage sludge (as dried and wet centrifuged samples) were reacted in ethanol in the presence of the appropriate combination of homogeneous Lewis-Brønsted acid catalysts, namely 1 %wt aluminium chloride hexahydrate and sulfuric acid respect to ethanol. After 6 h at 453 K, 99% of lipids and almost 60% of initial complex sugars were effectively converted into the abovementioned target products. Conversions and yields were quite similar to those obtained by reacting pure compounds singularly, confirming the robustness of the process and its applicability to differently composed sludge. At the end of the reaction, products were easily recovered and purified from the alcoholic phase, whereas only a very limited amount of solids remain as inert materials. Final refined biofuels have high calorific values (37 and 40 MJ kg−1) and actually represent the 68.5 and 59.2% of the initial energy content of starting sludge, respectively. This strategy combines valorization of the starting organic fraction of sewage sludge and a considerable reduction of final solid waste (in a stabilised form) to be disposed of. Finally, through a preliminary feasibility study, this acid ethanolysis resulted in a competitive alternative to the anaerobic digestion of mixed sewage sludge to obtain biofuels.

Biodiesel Production by Lipids From Indonesian strain of Microalgae Chlorella vulgaris

AbstractThe fatty acid methyl ester (FAME) production fromChlorella vulgarishas been studied by sequential investigation such as microalgae culturing, lipid extraction, and lipid conversion to FAME. TheC. vulgariscould grow well in the BG-11 medium and had a doubling time 3.7 days for its growth using inocula 16% (v/v). The optimum of dry cell biomass as 11.6 g/L was obtained after the microalgae culture harvested for 6 days. Lipid extraction from the biomass was carried out in various solvents and ultrasonication power, resulted lipid as 31% (w/w) when extracted with a mixed solvent of n-hexane-ethanol in ratio 1:1 and ultrasonication treatment at power 25 kHz/270W for 30 min. The lipid then converted to FAME through transesterification reaction with methanol using H2SO4catalyst at 45ºC for 2 h, and resulted FAME with area 32.26% in GC-MS analysis. The area was corresponded to FAME output as 13.68% (w/w). Fatty acid profiles of FAME obtained from GC-MS analysis showed the major peaks of fatty acids found inChlorella vulgariswere palmitic acid (C16:0), stearic acid (C18:0) and margaric acid (C17:0), and nonadecanoic acid (C19:0). Optimization of the transesterification reaction will be developed in future to improve the FAME product.

Biofuel production from microalgae: a review

The shortage of fossil fuels is actually a major economic issue in the context of increasing energy demand. Renewable energies are thus gaining in importance. For instance, microalgae-based fuels are viewed as an alternative. Microalgae are microscopic unicellular plants, which typically grow in marine and freshwater environments. They are fast growing, have high photosynthetic efficiency, and have relatively small land requirement and water consumption in comparison with conventional land crops biofuels. Nonetheless, selling biofuels is still limited by high cost. Here, we review biofuel production from microalgae, including cultivation, harvesting, drying, extraction and conversion of microalgal lipids. Cost issues may be solved by upstream and downstream measures: (1) upstream measures, in which highly productive strains are obtained by strain selection, genetic engineering and metabolic engineering, and (2) downstream measures, in which high biofuels yields are obtained by enhancing the cellular lipid content and by advanced conversion of microalgal biomass to biofuels. Maximum biomass and high biofuels production can be achieved by two-stage culture strategies, which is a win–win approach because it solves the conflicts between cell growth and biomass accumulation.

Production of high-quality biofuel via ethanol liquefaction of pretreated natural microalgae

The conversion of algal lipids to fatty acid alkyl esters is a promising way for the production of high-grade biofuel, due to the lower oxygen content of lipids than that of saccharides and proteins. Herein, a catalyst-free conversion process of natural microalgae cyanobacteria was developed for biodiesel production. The conversion involved two steps: (1) pretreatment of raw microalgae by Soxhlet extraction of lipids or hydrothermal treatment for extraction of saccharides and part of proteins at 200 °C; (2) liquefaction of raw and pretreated samples in sub/supercritical ethanol. In the first step, a maximum lipid yield of 6.5 wt% was extracted by Soxhlet extraction, while the hydrothermal treatment dissolved saccharides and a part of proteins. The composition of biocrude obtained from raw algae was complex, containing hydrocarbons, N-containing compounds, esters, fatty acids and other oxy-compounds. The biocrude from lipid extracted algae had a poor quality, from which the degradation of proteins was facilitated. Better yet, the extraction of saccharides and part of proteins by hydrothermal pretreatment simplified the composition (mainly fatty acid ethyl esters), reduced the nitrogen content (<4%) and improved the higher heating value (∼41 MJ kg−1) for biocrude.

Catalytic Hydrothermal Decarboxylation and Cracking of Fatty Acids and Lipids over Ru/C

Here, we report on the catalytic hydrothermal conversion of fatty acids and lipids to a range of hydrocarbons using Ru/C without the need for addition of external H2 supplies. Catalyst screening ex...

Biodiesel and biogas production from Isochrysis galbana using dry and wet lipid extraction: A biorefinery approach

Wet lipid extraction combined with residual biomass anaerobic digestion are alternatives to reduce the overall energy consumption of biodiesel production from microalgae. Solvents with different polarities have been studied to assess dry and wet lipid extraction process from Isochrysis galbana microalga. Ethyl acetate (EA) and a chloroform:methanol (CM) mixture yielded the best lipid extraction results in the dry and wet route with suitable lipid compositions. Fatty acid methyl esters (FAMEs) conversion of dry and wet extracted lipids with these solvents was performed by using both homogeneous (H2SO4) and heterogeneous (resin CT 269) catalysts. FAME production from wet extracted lipids with the EA solvent using the CT-269 resin constitutes an advantageous process because it avoids the water elimination step, and the CT-269 is a heterogeneous commercial catalyst, readily to separate after reaction. Lipid-spent microalga was anaerobically digested, obtaining that waste biomass from the wet extraction with EA had the highest methane yield (310 mL CH4/g volatile solids (VS). Energy balance analysis for FAMEs production with EA solvent (wet route) and heterogeneous catalyst yielded an energy recovery of about 80% in terms of biodiesel and biogas. Therefore, this process constitutes a promising route under an energy-driven microalga biorefinery.

Mechanism-Guided Design of Highly Efficient Protein Secretion and Lipid Conversion for Biomanufacturing and Biorefining.

Bacterial protein secretion represents a significant challenge in biotechnology, which is essential for the cost‐effective production of therapeutics, enzymes, and other functional proteins. Here, it is demonstrated that proteomics‐guided engineering of transcription, translation, secretion, and folding of ligninolytic laccase balances the process, minimizes the toxicity, and enables efficient heterologous secretion with a total protein yield of 13.7 g L−1. The secretory laccase complements the biochemical limits on lignin depolymerization well in Rhodococcus opacus PD630. Further proteomics analysis reveals the mechanisms for the oleaginous phenotype of R. opacus PD630, where a distinct multiunit fatty acid synthase I drives the carbon partition to storage lipid. The discovery guides the design of efficient lipid conversion from lignin and carbohydrate. The proteomics‐guided integration of laccase‐secretion and lipid production modules enables a high titer in converting lignin‐enriched biorefinery waste to lipid. The fundamental mechanisms, engineering components, and design principle can empower transformative platforms for biomanufacturing and biorefining.

Biodiesel Production (FAEEs) by Heterogeneous Combi-Lipase Biocatalysts Using Wet Extracted Lipids from Microalgae

The production of fatty acids ethyl esters (FAEEs) to be used as biodiesel from oleaginous microalgae shows great opportunities as an attractive source for the production of renewable fuels without competing with human food. To ensure the economic viability and environmental sustainability of the microbial biomass as a raw material, the integration of its production and transformation into the biorefinery concept is required. In the present work, lipids from wet Isochrysis galbana microalga were extracted with ethyl acetate with and without drying the microalgal biomass (dry and wet extraction method, respectively). Then, FAEEs were produced by lipase-catalyzed transesterification and esterification of the extracted lipids with ethanol using lipase B from Candida antarctica (CALB) and Pseudomonas cepacia (PC) lipase supported on SBA-15 mesoporous silica functionalized with amino groups. The conversion to FAEEs with CALB (97 and 85.5 mol% for dry and wet extraction, respectively) and PC (91 and 87 mol%) biocatalysts reached higher values than those obtained with commercial Novozym 435 (75 and 69.5 mol%). Due to the heterogeneous nature of the composition of microalgae lipids, mixtures with different CALB:PC biocatalyst ratio were used to improve conversion of wet-extracted lipids. The results showed that a 25:75 combi-lipase produced a significantly higher conversion to FAEEs (97.2 mol%) than those produced by each biocatalyst independently from wet-extracted lipids and similar ones than those obtained by each lipase from the dry extraction method. Therefore, that optimized combi-lipase biocatalyst, along with achieving the highest conversion to FAEEs, would allow improving viability of a biorefinery since biodiesel production could be performed without the energy-intensive step of biomass drying.

Catalytic Decomposition of the Oleaginous Yeast Cutaneotrichosporon Oleaginosus and Subsequent Biocatalytic Conversion of Liberated Free Fatty Acids

A single step catalytic cell wall lysis and triglyceride hydrolysis combined with the enzymatic conversion of lipids using the oleaginous yeast Cutaneotrichosporon oleaginosus (ATCC 20509) as a mod...

A Validation and Estimation of Total Eicosapentaenoic and Docosahexaenoic acids Using LC-MS/MS with Rapid Hydrolysis Enzymatic Method for Hydrolysis of Omega Lipids in Human Plasma and its Application in the Pharmacokinetic Study

Background:In this study, we have developed a novel, rapid enzymatic hydrolysis method for conversion of omega lipids (omega fatty acid triglycerides, phospholipids, omega conjugates) in to free fatty acids at room temperature using lipase and esterase enzymes. &lt;/P&gt;&lt;P&gt; Objective: To develop simple enzymatic hydrolysis and rapid sample extraction method for quantification of free (un-esterified) and conjugated (esterified) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) to provide the total EPA and DHA lipids present in human plasma. Quantification of total EPA/DHA was performed using liquid chromatography and tandem mass spectrometer instrument.Methods:The plasma sample is digested with lipase and esterase enzymes and extracted by using combined precipitation and liquid-liquid techniques. The LC-MS/MS method was optimized using EPA-D5 and DHA-D5 as labeled internal standards for EPA/DHA respectively. The analytical method is validated, utilized for simultaneous quantification of total EPA and DHA lipids in plasma collected from healthy human volunteers clinical study.Results:The reproducibility of the established enzymatic hydrolysis method was demonstrated by incurred sample reanalysis and the results for total EPA and DHA lipid were 93.33% and 96.67% respectively. The pharmacokinetic and statistical analysis was performed using baseline corrected concentration of total EPA and DHA lipids.Conclusion:The enzymatic hydrolysis method for conversion of omega fatty acid triglycerides, phospholipids, omega conjugates in to free fatty acid was reported first time for the quantitative application. The shorter time for sample workup procedure, simple enzymatic hydrolysis at room temperature and 3 minutes chromatography run time are well suitable for bioavailability/ bioequivalence studies.

Biodiesel production using lipase immobilised functionalized magnetic nanocatalyst from oleaginous fungal lipid

From the tannery effluent and oil contaminated soil different microbe were isolated and screened for high lipid content. Among all the isolates fungal strain SF2 showed high lipid content was selected and identified as Aspergillus niger. It was found that the fungi produced about 44.02% of lipid. The fatty acid composition was identified by gas chromatography. The physicochemical property of the extracted lipid was analysed. Magnetic nanoparticle was prepared and the lipase enzyme was immobilised on to the magnetic nanoparticle. Characterization of magnetic nanoparticle and enzyme immobilised magnetic nanoparticle was carried out. Esterase activity of both free enzyme and immobilised enzyme was analysed at different parameters in which immobilised enzyme showed better stability. The immobilised enzyme can be stored for 60 days without any loss in activity. Biodiesel was produced using the lipase immobilised on the magnetic nanoparticle. The optimum parameters for the fatty acid methyl ester production were investigated in terms of both physical and chemical parameters and the biodiesel yield under optimised reaction condition was 84%. The reusable stability of the catalyst was performed and it was found that the immobilised biocatalyst can be used for 5 cycles. The physio-chemical properties of the biodiesel was analysed and it was found to be within the limit specified by American society of testing materials standards. This work was firstly studied on the conversion of Aspergillus lipid into biodiesel by using lipase immobilised magnetic nanoparticle.

Effects of salinity and nitrogen source on growth and lipid production for a wild algal polyculture in produced water media

An algae polyculture (discovered in oil and gas produced water (PW) originating from a production facility in the Permian Basin of southwestern New Mexico) was composed primarily of Cyanobacterium aponinum, Parachlorella kessleri, with the remaining populations consisting of several species of halotolerant bacteria. The polyculture was tested in PW based media at a variety of different salinities and initial nutrient concentrations to determine the effects of these environmental conditions upon growth and lipid production. The polyculture exhibited growth rates of 46–51 mg ash free dry weight (AFDW)/L/D in PW over a salinity range from 15 to 60 g total dissolved solids (TDS)/L in PW containing nitrate as a nitrogen source. Growth was reduced at higher salinity. Biomass productivity in 60 g TDS/L PW was higher with ammonium as the nitrogen source (47.2–57 mg AFDW/L/D) than nitrate, with the highest growth observed using initial concentrations of 13 mg NH4-N and 1.7 PO4-P/L (single day growth of 99 mg AFDW/L/D). Of the conditions tested lipid productivity was greatest (around 12 mg lipids/L/D) at a salinity of 60 g TDS/L after phosphorus depletion (ammonium still present), and the maximum lipid content (48% of AFDW) after ammonium depletion (phosphate still present). Higher salinity, initial ammonium, and phosphate levels enriched for P. kessleri over C. aponinum, which also resulted in increased lipid content and productivity. Conversion of lipids to fatty acid methyl ester (FAME) created a profile dominated by palmitic (C16:0) and stearic (C18:0) acid and would produce a usable biodiesel. The results indicated that a mixed culture of C. aponinum, P. kessleri, and other micro fauna is a potential candidate for cultivation in brackish to hypersaline PW based media for the production of biomass and/or biofuels.

Conversion of Microbial Lipids to Biodiesel and Basic Lab Tests for Analysis of Fuel-Quality Parameters.

This chapter describes lab-scale procedures for the direct conversion of microbial lipids to fatty acid methyl esters (FAMEs) for use as biodiesel fuel. Methods for the gas chromatography analysis of FAME profiles and equations to predict several fuel-quality parameters are detailed herein. This chapter also provides a complete list summarizing each of the fuel quality tests (e.g., sample size and equipment) that are required by ASTM International D6751 regulations for pure biodiesel fuel (B100) or blend stock. Recommendations for the decolorization of microbial lipid sources containing pigments are also included. This resource should provide a guide to basic conversion and characterization of microbial-derived biodiesel fuels and a roadmap for more-detailed testing required to assess commercial feasibility.