Conversion Of Lipids Research Articles

Biodiesel from black soldier fly larvae grown on restaurant kitchen waste

Biodiesel from insect larvae is an alternative to plant biodiesel, which have issues of using edible plants. On the contrary, insects can grow on waste. Although the conversion of larval lipids to biodiesel is known, characterisation of larval biodiesel is rarely reported. Here, black soldier fly larvae were cultivated for 20 days on kitchen waste. Larval lipids were extracted and converted to biodiesel by two-step transesterification. Analysis by optical polarisation microscopy from − 5 to + 15 °C showed tiny needle-like shaped crystals. Fourier transform infrared spectra of black soldier fly biodiesel revealed absorption bands at 1459 and 1435 cm−1 corresponding to methyl ester, the main functional group of biodiesel. Nuclear magnetic resonance (NMR) analysis confirmed the presence of methyl ester by showing peaks at 3.6 and 2.3 ppm by 1H NMR, and at 176 and 51.56 ppm by 13C NMR. Overall, our results confirm the successful conversion of black soldier fly larval lipid to biodiesel. This biodiesel met the American Society for Test and Materials D6751 and European Standard 14214.

Influence of preparation methods on physicochemical properties of zirconia for transesterification of Nannochloropsis oculata microalga’s oil

In this study, zirconia was successfully synthesized using precipitation, sol-gel and hydrothermal methods. The effect of different preparation methods on the physicochemical properties of zirconia were studied using FTIR, surface area and pore analyzer, XRD, FESEM, NH3-TPD and CO2-TPD. The performance of synthesized zirconia as heterogeneous catalyst to convert Nannochloropsis oculata (N. oculata) oil to biodiesel was also investigated. FTIR results confirmed that the selected calcination temperature is suitable for complete decomposition of organic components and the formation of zirconia phase. It was found that zirconia synthesized using precipitation method shows the highest surface area. However, zirconia synthesized by sol-gel method shows the highest composition of tetragonal crystallite structure. All the samples possess both the acid and basic sites with different strength. The highest lipid conversion (67.86 %) is obtained using zirconia synthesized using sol-gel method.

Biodiesel synthesis from wastewater grown microalgal feedstock using enzymatic conversion: A greener approach

Commercial scale microalgal biodiesel production is still challenging due to high cultivation cost and inefficient conversion technologies. This work explicated an economical cultivation strategy using anaerobic centrate as growth medium of Acutodesmus obliquus. Among various modes evaluated maximum lipid productivity of 57.03 mgL−1d−1 was achieved under mixotrophic cultivation condition using anaerobic centrate. Conversion of microalgal lipids to biodiesel using immobilized Candida rugosa lipase was investigated. Reaction parameters viz. temperature, methanol to oil molar and enzyme amount were optimized using response surface methodology. Best conversion of 95.36% was achieved at 50 °C, methanol to oil ratio of 3:1 and 15% enzyme amount based on oil weight. Immobilized C. rugosa lipase can be used for 5 batches without much loss in conversion efficiency (>90%). Most of the fuel properties comply with ASTM and EN standards.

101. Lipoprotein turnover and possible remnant accumulation in preeclampsia: Insights from the Freiburg preeclampsia H.E.L.P.-Apheresis Study

Introduction Preeclampsia is a potentially life threatening disease occurring in pregnancy. The only causative cure consists in delivery with all the risks for a premature fetus. In preeclampsia, the lipid metabolism is substantially altered and lipid apheresis is being explored as a possible therapeutic approach to prolong preeclamptic pregnancies and allow further maturation of the fetus. In the Freiburg H.E.L.P.-Apheresis Study, 6 early onset preeclamptic patients were treated with H.E.L.P. apheresis. Objective/hypothesis Detailed analysis of apheresis-induced dynamics in serum lipid parameters. Methods 6 early onset preeclamptic patients underwent repeated apheresis treatments (n = 23). We evaluated parameters of the lipoprotein metabolism in 6 preeclamptic patients in detail. Results Reduction of lipoproteins by apheresis was lower than theoretically expected. Lipids reached previous pre-apheresis levels before the next apheresis even though apheresis was repeated within 2.9 ± 1.2 days. Fractional catabolic rates and synthetic rates were found to be substantially elevated, with fractional catabolic rates for ApoB/ LDL-cholesterol being 0.7 ± 0.3/ 0.4 ± 0.2 [day−1] and synthetic rates being 26 ± 8/ 17 ± 8 [mg*kg−1*day−1]. The distribution of LDL-subclasses after apheresis shifted to larger buoyant LDL, while IDL levels remained unaffected. Discussion Apheresis induced changes in lipoprotein profiles point to an underlying remnant removal disease like imbalance in plasma lipid conversion during preeclamptic conditions.

Lipid Conversion by Cell-Free Synthesized Phospholipid Methyltransferase Opi3 in Defined Nanodisc Membranes Supports an in Trans Mechanism.

Biomembranes composed of lipids and proteins play central roles in physiological processes, and the precise balance between different lipid species is crucial for maintaining membrane function. One pathway for the biosynthesis of the abundant lipid phosphatidylcholine in eukaryotes involves a membrane-integrated phospholipid methyltransferase named Opi3 in yeast. A still unanswered question is whether Opi3 can catalyze phosphatidylcholine synthesis in trans, at membrane contact sites. While evidence for this activity was obtained from studies with complex in vitro-reconstituted systems based on endoplasmic reticulum membranes, isolated and purified Opi3 could not be analyzed. We present new insights into Opi3 activity by characterizing the in vitro-synthesized enzyme in defined hydrophobic environments. Saccharomyces cerevisiae Opi3 was cell-free synthesized and either solubilized in detergent micelles or co-translationally inserted into preformed nanodisc membranes of different lipid compositions. While detergent-solubilized Opi3 was inactive, the enzyme inserted into nanodisc membranes showed activity and stayed monomeric as revealed by native mass spectrometry. The methylation of its lipid substrate dioleoylphosphatidylmonomethylethanolamine to phosphatidylcholine was monitored by one-dimensional 31P nuclear magnetic resonance. Phosphatidylcholine formation was observed not only in nanodiscs containing inserted Opi3 but also in nanodiscs devoid of the enzyme containing the lipid substrate. This result gives a clear indication for in trans catalysis by Opi3; i.e., it acts on the substrate in juxtaposed membranes, while in cis lipid conversion may also contribute. Our established system for the characterization of pure Opi3 in defined lipid environments may be applicable to other lipid biosynthetic enzymes and help in understanding the subcellular organization of lipid synthesis.

Conversion of Palmitic Acid Over Bi-functional Ni/ZSM-5 Catalyst: Effect of Stoichiometric Ni/Al Molar Ratio

The conversion of the biomass-derived lipid, lignocellulosic and carbohydrate resources into renewable platform intermediates, chemicals and biofuels has been lately increasing in interest. The mechanistic reaction pathways, like hydro-deoxygenation, decarboxylation and hydrocracking, of the selected palmitic acid, as a model fatty acid, over Ni/ZSM-5 zeolite catalysts were studied. The ZSM-5 material with different Al/Si molar ratios was synthesized via a green template-free hydrothermal synthesis procedure, treated and subsequent functionalised with various Ni metal loadings. However, Ni/Al molar ratio was kept stoichiometric (Ni/Al = 0.5). The characteristic physicochemical properties of composite catalysts were studied by numerous characterization techniques, such as X-ray powder diffraction (XRD), scanning-, as well as high-resolution transmission electron microscopy (SEM/HRTEM), and X-ray photoelectron spectroscopy (XPS). NiO with an average particle size of 10–20 nm was found on ZSM-5 support. The relative Ni/Al atom fraction in Ni/ZSM-5 systems influenced their Lewis/Bronsted acidic sites, as well as the external exposed area of prepared heterogeneous structures. Furthermore, the mentioned morphological parameters affected predominant catalytic routes. Species’ production mechanism, as a consequence of Lewis/Bronsted centre weak/strong acidity, as well as their integral concentration, was proposed, mirroring the observed process kinetics, selectivity and turnover. It was demonstrated that the main obtained products were esters, aldehydes, alcohols, hydrocarbons and gases (CO2, CO…), produced by deoxygenation (e.g. decarbonylation), hydrogenation and cracking, less, though, through isomerisation.

Direct transesterification of Mucor circinelloides biomass for biodiesel production: Effect of carbon sources on the accumulation of fungal lipids and biofuel properties

The wild strain of Mucor circinelloides URM 4182 from a Brazilian culture collection was previously recognized as potential oleaginous microorganism that supplied single cell oil (SCO) with suitable properties for biodiesel synthesis. This work focused on assessing the accumulation of storage lipid by this strain grown in various media containing different carbon sources and the subsequent conversion of the microbial lipids into biodiesel. The chosen carbon sources can be obtained from several agro-industrial residues such as sucrose and fructose (sugarcane molasses), xylose (hydrolysate of lignocellulosic materials like sugarcane bagasse), starch (corn milling), ethanol and glycerol (byproducts from biodiesel production). The carbon source was found to influence the obtained fatty acid profile of M. circinelloides oil, realizing important attributes that favor its use for biodiesel production, including good levels of saturated (Cn: 0) and monounsaturated (Cn: 1) fatty acids. Polyunsaturated fatty acids with two (linoleic acid) or three double (linolenic acid) bonds were also found, but their concentrations decreased from 33.2 to 19.8% when glucose was replaced by a substrate based on sucrose. The feasibility of using low-cost feedstocks in the synthesis of microbial lipids was demonstrated, with the exception of ethanol that inhibited fungal growth. The lipid-bearing biomass was then subjected to direct transesterification using a robust solid acid catalyst (12-molybdophosphoric acid supported on alumina) in a high-pressure reactor, producing ethyl esters as biodiesel material with very high conversion yields (98.5%) and minor levels of byproducts.

Solvent-free catalytic deoxygenation of oleic acid via nano-Ni/HZSM-5: Effect of reaction medium and coke characterization

Non-H2 and solvent-free catalytic conversion of waste lipids to liquid hydrocarbons is of great interest because of the associated low-cost, full-safety, and easy-operability. In this work, a solvent-free catalytic process for deoxygenating oleic acid was performed in H2 and non-H2 (N2, CH4, and CO2) media over nano-Ni/HZSM-5. 8-Heptadecene, a primary product obtained at 320 °C in four media, was derived from the straightforward decarboxylation of oleic acid. In non-H2 medium at 360 °C, the formation of C8–C15 alkanes was enhanced, with yields of ca. 65.05 mol%, 70.71 mol%, and 73.09 mol% for N2, CH4, and CO2, respectively. A low yield of 49.67 mol% C8–C15 alkanes in H2 medium suggested that the H2 medium reduced catalytic cracking. This was due to the preferential formation of stable heptadecane from 8-heptadecene in the presence of abundant H2. The absence of H2 favored the cracking of 8-heptadecene. These cracked products were further converted to C8–C15 alkanes, for which a mass supply of hydrogen was mandatory. Gas-phase reactions including methanation, Fisher-Tropsch (F-T) synthesis, and water-gas shift (WGS) reactions between deoxygenated gas products and reaction media provided significant pathways for the hydrogen required for the formation of alkanes. The CH4 medium also acted as a hydrogen source due to its decomposition, catalyzed by nano-Ni/HZSM-5. Coke was substantially formed in all the four media. It was highlighted that the medium of H2 favored the formation of aliphatic cokes, whereas the non-H2 media, particularly the CO2 medium, facilitated aromatic coke species on account of its weak oxidizability. Additionally, there was a severe loss of loaded Ni nanoparticles under H2 medium but a slight Ni loss in CO2 medium, which was proposed to the reason of aromatic cokes formation at the catalyst surface, acting as a trap for the loaded Ni nanoparticles.

The synchronous TAG production with the growth by the expression of chloroplast transit peptide-fused ScPDAT in Chlamydomonas reinhardtii

BackgroundThe synchronous triacylglycerol (TAG) production with the growth is a key step to lower the cost of the microalgae-based biofuel production. Phospholipid: diacylglycerol acyltransferase (PDAT) has been identified recently and catalyzes the phospholipid contributing acyl group to diacylglycerol to synthesize TAG, and is considered as the important source of TAG in Chlamydomonas reinhardtii.ResultsUsing a chimeric Hsp70A–RbcS2 promoter, exogenous PDAT form Saccharomyces cerevisiae fused with a chloroplast transit peptide was expressed in C. reinhardtii CC-137. Proved by western blot, the expression of ScPDAT showed a synchronous trend to the growth in the exponential phase. Compared to the wild type, the strain of Scpdat achieved 22% increase in the content of total fatty acids and 32% increase in TAG content. In addition, the fluctuation of C16 series fatty acid in monogalactosyldiacylglycerol, diacylglyceryltrimethylhomoserine and TAG indicated an enhancement in the TAG accumulation pathway.ConclusionThe TAG production was enhanced in the regular cultivation without the nutrient stress by strengthening the conversion of polar lipid to TAG in C. reinhardtii and the findings provide a candidate strategy for rational engineered strain to overcome the decline in the growth during the TAG accumulation triggered by nitrogen starvation.

Conversion and recovery of saponifiable lipids from microalgae using a nonpolar solvent via lipase-assisted extraction

A single-step method for transesterifying and recovering lipids in concentrated slurries (ca 20% w/w solids) of ruptured microalgae is presented. A soluble Rhizomucor miehei lipase (RML) was used to directly transesterify the lipids in the marine microalgae Nannochloropsis salina. This allowed both triglycerides (TAG) and polar saponifiable lipids to be recovered as fatty acid methyl esters (FAME) using a nonpolar solvent (hexane). Up to 90 wt% of the total saponifiable lipids (SL) were converted to FAME within 24 h, approximately 75% of which was recovered in the hexane by centrifugation. Two pathways for the conversion and recovery of polar lipids were identified. The water in the slurry buffered against potential lipase inhibition by methanol, but necessitated a high methanol dose for maximal FAME conversion. Nonetheless the method enables the recovery of polar lipids as FAME while avoiding the need for both drying of the biomass and a downstream transesterification step.

Combining evolutionary and metabolic engineering in Rhodosporidium toruloides for lipid production with non-detoxified wheat straw hydrolysates.

Improving the yield of carbohydrate to lipid conversion and lipid productivity are two critical goals to develop an economically feasible process to commercialize microbial oils. Lignocellulosic sugars are potential low-cost carbon sources for this process but their use is limited by the toxic compounds produced during biomass pretreatment at high solids loading, and by the pentose sugars (mainly xylose) which are not efficiently metabolized by many microorganisms. Adaptive laboratory evolution was used to select a Rhodosporidium toruloides strain with robust growth in non-detoxified wheat straw hydrolysates, produced at 20% solids loading, and better xylose consumption rate. An arabinose-inducible cre-lox recombination system was developed in this evolved strain that was further engineered to express a second copy of the native DGAT1 and SCD1 genes under control of the native xylose reductase (XYL1) promoter. Fed-batch cultivation of the engineered strain in 7-L bioreactors produced 39.5g lipid/L at a rate of 0.334g/Lh-1 and 0.179g/g yield, the best results reported in R. toruloides with non-detoxified lignocellulosic hydrolysates to date.

Heat shock‐induced metabolic conversion of membrane lipids, fatty acids and volatile organic compounds of Pyropia haitanensis under different heat shock time

SUMMARYLipid metabolites play an important role in understanding the stress physiology of Pyropia haitanensis, and can be used to facilitate development of stress‐resistant Pyropia cultivars. Therefore, in this study ultra performance liquid chromatography coupled with quadrupole time of flight mass spectrometry (UPLC‐Q‐TOF‐MS) and gas chromatography–mass spectrometry (GC–MS) based metabolomics approaches were developed to screen the responses of lipid metabolites such as phospholipids, glycolipids, fatty acids and volatile organic compounds (VOCs) to different heat shock times. A total of 26 potential lipid biomarkers including Lyso‐monogalactosyldiacylglycerol (Lyso‐MGDG), Lyso‐digalactosyldiacylglycerol (Lyso‐DGDG), sulfoquinovosylmonoacylglycerols (SQMG), sulfoquinovosyldiacylglycerol (SQDG), diacylglyceryltrimethylhomoserine (DGTS), triacylglycerol (TAG), Lyso‐phosphatidicacid (Lyso‐PA), Lyso‐phosphatidylcholine (Lyso‐PC), Lyso‐phosphatidylethanolamine (Lyso‐PE), Lyso‐phosphatidylglycerol (Lyso‐PG), phosphatidylglycerol (PG), phosphatidylinositol (PI), and phosphatidylinositol phosphate (PIP) were identified, most of which responded to high temperature by reducing or increasing levels after stimulation for 1 h or 6 h. After times longer than 6 h, the levels of most lipids gradually recovered to the control group levels. Moreover, the balance of lipids and fatty acids transformation was disrupted. Overall, 11 total fatty acids (TFAs), 13 free fatty acids (FFAs) and 29 VOCs were identified during 0–72 h of high temperature stress. The FFAs, especially polyunsaturated C 20 fatty acids and VOCs, showed opposing change trends, indicating the transformation between C 20 fatty acids and VOCs. Overall, this study provides important insights into the metabolic variations of P. haitanensis under different heat shock time and the relationship between the conversion of lipids, fatty acids, and VOCs. The information provided herein will facilitate efficient development and improvement of Pyropia quality by producing cultivars resistant to high temperature.

GC-MS-Based Analysis of Methanol: Chloroform-extracted Fatty Acids from Plant Tissues.

Fatty acids (FAs) are carboxylic acids with long aliphatic chains that may be straight, branched and saturated or unsaturated. Most of the naturally occurring plant FAs contains an even number of carbon (C4-C24). FAs are used in food and pharmacological industries due to their nutritional importance. In addition, FAs are considered as a promising alternative for the production of biodiesel from terrestrial plant biomass. To establish commercial applications, more reliable analytical methods are needed for the identification, quantification, and composition determination of FAs. Here, we describe a relatively rapid and sensitive method for the extraction, identification, and quantification of FAs from a small quantity of plant tissue. The method includes steps of lipid extraction, conversion of lipid to fatty acid methyl esters (FAMEs) by transmethylation, identification and quantification of FAMEs using gas chromatography-mass spectrometry (GC-MS). In this protocol, an internal standard is added prior to GC-MS analysis. The amount of each FA is calculated from its peak area relative to the peak area of the internal standard.

Mechanistic in-operando FT-IR studies for hydroprocessing of triglycerides

In-operando measurements were carried out for the first time to identify different intermediates and primary products formed during the conversion of lipids for catalytic as well as non-catalytic thermal hydroprocessing. Hydroprocessing of lipids was carried at 280–300 °C temperature, 40–60 bar pressure, 1500 Nl/L H2/Feed ratio and 1 h−1 space velocity in a fixed-bed tubular reactor. A high pressure metallic probe was used for collecting the FTIR spectra under these conditions. Under these conditions although the conversion of triglyceride molecules were complete, the deoxygenation reactions were less than 1%, with 6–7% carbon loss and 17–18% hydrogen loss into the gaseous phase corresponding to propane. In-operando FT-IR studies confirmed that depropanation (propane removal) is the primary reaction during catalytic hydroprocessing of triglycerides, along with formation of intermediates. For thermal hydroprocessing wide range of intermediates – alcohols, alkenes, ketones, anhydrides, ethers, acids, aldehyde and esters – were observed. Such intermediates indicate several undesirable coupling reactions such as CC bond formation, esterification, etherification and ketonization. For catalytic hydroprocessing only selective product intermediates were observed. Triglycerides hydroprocessing over Pd/Al2O3 catalyst predominantly produced carboxylic acid and aldehyde intermediates, along with very weak bands due to aromatics. Pd/C predominantly produced aldehydes with weak bands due to ketones. Sulfided CoMoP/Al2O3 catalyst also produced aldehydes predominantly, but also small quantities of carboxylic acids as intermediates, from trigycerides. IR bands due to alcohols, ethers, aromatics and cyclic ketones were observed at the later stage of reaction over CoMoP(S)/Al2O3 catalyst.

Raman Deuterium Isotope Probing Reveals Microbial Metabolism at the Single-Cell Level.

We illustrate that single-cell Raman microspectroscopy, coupled with deuterium isotope probing (Raman-DIP), provides a culture-independent and nondestructive approach to probe metabolic pathways of carbon substrates at the single-cell level. We found a distinguishable C-D vibration band at 2070-2300 cm-1 in single-cell Raman spectra (SCRS) when Escherichia coli used deuterated glucose and Pseudomonas sp. used deuterated naphthalene as sole carbon sources. The intensity of the C-D band is proportional to the extent of deuteration in the carbon source, and as little as 5% deuteration can be distinguished by analysis of SCRS. It suggests that Raman-DIP could be used to semiquantitatively and sensitively indicate the metabolism of deuterated carbon source in microbes. A lower lipid conversion rate of deuterated naphthalene compared to that of deuterated glucose was observed, presumably owing to different anabolic pathways and membrane alteration. Apart from the C-D band shift from C-H, SCRS also reveal several isotopic shifts of the phenylalanine band, of which the positions correlate well with a computational model. A reduction in phenylalanine deuteration in Pseudomonas sp. compared to that in E. coli is due to the dilution effect of different pathways of phenylalanine biosynthesis in Pseudomonas sp. Collectively, we demonstrate that Raman-DIP can not only indicate metabolic activity using deuterated carbon sources but also reveal different metabolic pathways by analyzing SCRS. By harnessing such low-cost and versatile deuterated substrates, Raman-DIP has the potential to probe a wide range of metabolic pathways and functions at the single-cell level.

Solvo-thermal in situ transesterification of wet spent coffee grounds for the production of biodiesel

This work addresses non-catalytic biodiesel production from spent coffee ground (SCG) by integrating solvo-thermal effect of 1,2-dichloroethane (DCE) with in situ transesterification over 160 °C. The SCG water content has a positive effect on the DCE hydrolysis up to 60 wt% due to the bimolecular substitution mechanism. The hydrolysis gives an acidic environment favorable for cellulose decomposition, SCG particle size reduction and lipid conversion. The optimal fatty acid ethyl ester yield was 11.8 wt% based on the mass of dried SCG with 3.36 ml ethanol and 3.16 ml DCE at 196.8 °C through the response surface methodology. Using the solvo-thermal effect, direct utilization of wet SCG as a biodiesel feedstock provides not only economic feasibility without using drying process and additional acid catalyst but also environmental advantage of recycling the municipal waste.

Conversion of Chlamydomonas sp. JSC4 lipids to biodiesel using Fusarium heterosporum lipase-expressing Aspergillus oryzae whole-cell as biocatalyst

Lipid from Chlamydomonas sp. JSC4 was used as a feedstock for biodiesel production. The lipid was found to contain high amounts of phospholipids and free fatty acid in addition to the triglycerides. Two enzymatic methods for the efficient conversion of the heterogenous lipid to fatty acid methyl esters (FAME) were carried out. The method using either a lipase cocktail containing Candida cylindracea lipase and Thermomyces lanuginosus lipase combination (m I) or immobilized Fusarium heterosporum lipase-expressing Aspergillus oryzae whole-cells (m II) were both successful. However, the method using lipase cocktail showed 30.8% relative stability after the fourth batch, whereas the whole-cell biocatalyst showed 98.1%. Although the whole-cell biocatalyst tolerated a wide range of water content, an exploration of the effect of water-methanol interaction on the biocatalytic process showed that 24% water and 7:1 methanol to oil ratio is more favorable for FAME production. A higher initial methanol consumption rate facilitated a more stable system with the whole-cell biocatalyst, producing over 97% FAME in 32h. The efficient conversion of a highly heterogenous substrate in the presence of high amounts of water could be an effective technique for the enzymatic conversion of microalgal lipids.

Process intensification of biodiesel production from Chlorella sp. MJ 11/11 by single step transesterification

The present study investigates the effect of single step transesterification method for the improvement of biodiesel yield using algal biomass. Different photobioreactor configurations were studied to find out the most suitable reactor for biomass production. Suitable conditions for HCl catalyzed transesterification were determined for the improvement of biodiesel production. Maximum lipid conversion (95%) was observed under catalyst concentration, algal biomass/methanol ratio, reaction temperature, reaction time and biomass drying duration of 4M, 1:5, 65°C, 7h and 90min, respectively. Single step transesterification showed significant improvement in lipid conversion as compared to conventional two steps transesterification. The kinetics and thermodynamics of the reaction was also determined. The results could help in development of sustainable technology with improved biodiesel quality.

Spatiotemporal Control of Lipid Conversion, Actin-Based Mechanical Forces, and Curvature Sensors during Clathrin/AP-1-Coated Vesicle Biogenesis

Clathrin/adaptor protein-1-coated carriers connect the secretory and the endocytic pathways. Carrier biogenesis relies on distinct protein networks changing membrane shape at the trans-Golgi network, each regulating coat assembly, F-actin-based mechanical forces, or the biophysical properties of lipid bilayers. How these different hubs are spatiotemporally coordinated remains largely unknown. Using invitro reconstitution systems, quantitative proteomics, and lipidomics, as well as invivo cell-based assays, we characterize the protein networks controlling membrane lipid composition, membrane shape, and carrier scission. These include PIP5K1A and phospholipase C-beta 3 controlling the conversion of PI[4]P into diacylglycerol. PIP5K1A binding to RAC1 provides a link to F-actin-based mechanical forces needed to tubulate membranes. Tubular membranes then recruit the BAR-domain-containing arfaptin-1/2 guiding carrier scission. These findings provide a framework for synchronizing the chemical/biophysical properties of lipid bilayers, F-actin-based mechanical forces, and the activity of proteins sensing membrane shape during clathrin/adaptor protein-1-coated carrier biogenesis.

Conversion of lipids from wet microalgae into biodiesel using sulfonated graphene oxide catalysts

Four solid acid catalysts including graphene oxide (GO), sulfonated graphene oxide (SGO), sulfonated graphene (SG), and sulfonated active carbon (SAC) were used to convert lipids in wet microalgae into biodiesel. The physiochemical properties of the catalysts were characterized with scanning electron microscope, X-ray diffraction, and thermogravimetric analysis. SGO provided the highest conversion efficiency (84.6% of sulfuric acid) of lipids to fatty acid methyl esters (FAME). Whereas SAC converted few lipids into FAME. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and elemental analysis revealed that much higher hydrophilic hydroxyl content in SGO catalyst resulted in a considerable higher conversion efficiency of lipids to FAME than that (48.6%) catalyzed by SG, although SO3H groups (0.44mmol/g) in SGO were less than those (1.69mmol/g) in SG. Given its higher SO3H group content than GO (0.38mmol/g), SGO had higher conversion efficiency than GO (73.1%), when they had similar hydrophilic hydroxyl contents.