Aleuritic Acid Research Articles

Sustainable N-Formylation of Anilines: Harnessing Aleuritic Acid as a Renewable Formyl Source

Abstract N-Formylation of anilines using a renewable aleuritic acid as an eco-friendly and sustainable formylating source has been developed. para-Substituted anilines generally provided good yields, while moderate yields were observed with meta- and ortho-substituted derivatives. In situ generated formic acid through oxidative cleavage of aleuritic acid serve as a formyl source, which has been confirmed through control experiments.

Characterization and identification of an archaeological “lacquer” pipe

A pipe with red coating on the surface was excavated from an archaeological site in Sweden, which is supposed to be a lacquer ware imported from China due to the admiration and pursue of lacquer wares from Asia by Europeans during sixteenth to eighteenth centuries. However, materials such as shellac and resins were often used to imitate lacquer during that time in Europe. To determine whether the pipe was Chinese lacquer ware or not, attenuated total reflection of fourier transform infrared spectroscopy (ATR-FTIR), thermally-assisted hydrolysis and methylation pyrolysis gas chromatography-mass spectrometry (THM-Py-GC/MS) were conducted. The detection of significant amount of aleuritic acid, laccijalaric acid, laccishellolic acid, shellolic acid and jalaric acid represents that shellac is the main material used for the pipe coating rather than Chinese lacquer. Long chain fatty alcohols were found in the sample, indicating that the shellac is un-dewaxed. In addition, pine resin and turpentine were also found as additives in the pipe coating. Furthermore, pigments in the coating were determined as cinnabar and carbon black by scanning electron microscopy with element energy dispersive spectroscopy (SEM–EDS) and Raman spectroscopy. The results could definitely support the conservation of the pipe, and also provide the evidence of the cultural exchange between Europe and Asia.

Microwave-assisted extraction and purification of aleuritic acid from seedlac: A fast, eco-friendly and cost-effective single process for enhanced yield and purity

Aleuritic acid is one of the high-value constituents of lac resin, which has a massive demand in the perfumery industry for synthesizing macrocyclic lactones. The commercial aleuritic acid extraction process is lengthy, inefficient, and produces low-quality aleuritic acid, which necessitates repeated purification using toxic chemicals, bleaching agents, organic solvents, and activated carbon to obtain the desired quality aleuritic acid. This study developed a single process for extraction and purification of aleuritic acid involving microwave-assisted hydrolyzing of the seed lac and removing impurities of lac resin through condensation and alkali heat treatment. The novel process has reduced the overall extraction time from 15 days to 1.5–2 days and increases the yield from 35 to 40 % to 85–86 % and purity from 70 to 86 % to > 98 % in a single process without the use of toxic chemicals, bleaching agents, or organic solvents, unlike the commercially available process. HPLC, FT-IR, DSC, and FESEM techniques were employed to characterize and evaluate the quality of the extracted aleuritic acid. The developed process is highly efficient and cost-effective and offers scalable and fast extraction while requiring minimal chemicals, labor, and energy compared to alternative processes. Moreover, it exhibits greater environmental sustainability.

DFT study on the polymerization mechanism of aleuritic acid and jalaric acid in shellac molecule

Shellac is a natural resin composed of a complex mixture of hydroxy aliphatic acids, primarily aleuritic acid (AA), and sesquiterpenoid acids such as jalaric acid (JA). The paper puts forth valuable information on the polymerization mechanism considering AA and JA using Gaussian 16.0 software. Computations of energy, thermochemical values, and molecular orbital coefficients have been done using both Hartree-Fock (HF) and Density Functional Theory (DFT) to establish the mechanism. Global reactivity parameter study revealed that monomers of the shellac are hard whereas the polymer units are soft. HOMO-LUMO, ESP and theoretical FTIR results are coherent with the previously reported works for the prediction of possible polymeric species present in the shellac along with their thermodynamic stability. This is the first attempt to predict the linkages in shellac resin. This study helps understand the mechanism of formation of lac polymer and also highlights the associated properties of shellac.

Recovery of Lac Resin from the Aqueous Effluent of Shellac Industry

Shellac and aleuritic acid manufacturing industries generate a lot of alkaline aqueous effluent during the process of manufacture of shellac and aleuritic acid from the seedlac/sticklac. The generated effluent contains lac resin, lac wax, lac dye and other water-soluble organic acids. Shellac industries in India face problems with the disposal of aqueous effluent due to the presence of considerable amounts of natural organic molecules and the dark colour solution. To address these problems, we have developed a novel method for the selective recovery of the lac resin from the alkaline aqueous effluent of shellac manufacturing industry. The recovered lac resin has been characterized by 13C-NMR, FT-IR and melting point and the data were compared with standard industrial-grade resin. The recovered lac resin was evaluated by the lac manufacturing industry for commercial applications.

Improved extraction and recrystallization of high-quality aleuritic acid from natural resins using a modified technique

ABSTRACT The current extraction procedures for aleuritic acid from natural resins (seedlacs) are time-consuming and provide a variable yield of 10–20% with a purity of 70–94%. Furthermore, the perfume industries do not consider this low purity level to be a viable starting material for commercial purposes, since it necessitates further purification by multistage crystallization, resulting in 40–50% aleuritic acid losses. The current study developed a modified extraction method that combines alkaline hydrolysis with a salting-out mechanism and a polarity-manipulated solvent system suited for purification via a single-step recrystallization procedure. The extraction method consistently produces 17–18 grams of aleuritic acid per 100 grams of fresh resins, with a purity of > 99% and a melting point of 100 0C. Furthermore, the developed recrystallization technique resulted in a recovered yield of 85–95%, unlike the traditional recrystallization techniques, which results in yield losses of 40–50%. The purity of aleuritic acid was determined using HPLC equipped with an RI detector, and the melting points and crystals were characterized using Differential Scanning Calorimetry and Field Emission Scanning Electron Microscope. The new approach was less expensive, more ecologically friendly, and provides standard-quality aleuritic acid while using fewer chemicals.

A new method for shellac binder detection in ancient building mortars

Shellac, also known as lac, is composed mainly of aleuritic acid.

Mycobacterium tuberculosis Endonuclease VIII 2 (Nei2) forms a prereplicative BER complex with DnaN: Identification, characterization, and disruption of complex formation.

Mycobacterium tuberculosis Nei2 (Rv3297) is a BER glycosylase that removes oxidized base lesions from ssDNA and replication fork-mimicking substrates. We show that Endonuclease VIII 2 (Nei2) forms a BER complex with the β-clamp (DnaN, Rv0002) with a KD of 170nM. The Nei2-β-clamp interactions enhance Nei2's activities up to several folds. SEC analysis shows that one molecule of Nei2 binds to a single β-clamp dimer. Nei2 interacts with subsites I and II of the β-clamp via a noncanonical 223 QGCRRCGTLIAY239 Clamp Interacting Protein (CIP) motif in the C-terminal zinc-finger domain, which was previously shown by us to be dispensable for intrinsic Nei2 activity. The 12-mer peptide alone exhibited a KD of 10.28nM, suggesting that the motif is a key mediator of Nei2-β-clamp interactions. Finally, we identified inhibitors of Nei2-β-clamp interactions using rational methods, in vitro disruption, and SPR assays after querying a database of natural products. We found that Tubulosine, Fumitremorgin C, Toyocamycin, and Aleuritic acid exhibit IC50 values of 94.47, 83.49, 109.7, and 71.49µM, respectively. They act by disrupting Nei2-β-clamp interactions and do not affect intrinsic Nei2 activity. Among other things, the present study gives insights into the role of Nei2 in bacterial prereplicative BER.

Zinc Polyaleuritate Ionomer Coatings as a Sustainable, Alternative Technology for Bisphenol A-Free Metal Packaging.

Sustainable coatings for metal food packaging were prepared from ZnO nanoparticles (obtained by the thermal decomposition of zinc acetate) and a naturally occurring polyhydroxylated fatty acid named aleuritic (or 9,10,16-trihydroxyhexadecanoic) acid. Both components reacted, originating under specific conditions zinc polyaleuritate ionomers. The polymerization of aleuritic acid into polyaleuritate by a solvent-free, melt polycondensation reaction was investigated at different times (15, 30, 45, and 60 min), temperatures (140, 160, 180, and 200 °C), and proportions of zinc oxide and aleuritic acid (0:100, 5:95, 10:90, and 50:50, w/w). Kinetic rate constants calculated by infrared spectroscopy decreased with the amount of Zn due to the consumption of reactive carboxyl groups, while the activation energy of the polymerization decreased as a consequence of the catalyst effect of the metal. The adhesion and hardness of coatings were determined from scratch tests, obtaining values similar to robust polymers with high adherence. Water contact angles were typical of hydrophobic materials with values ≥94°. Both mechanical properties and wettability were better than those of bisphenol A (BPA)-based resins and most likely are related to the low migration values determined using a hydrophilic food simulant. The presence of zinc provided a certain degree of antibacterial properties. The performance of the coatings against corrosion was studied by electrochemical impedance spectroscopy at different immersion times in an aqueous solution of NaCl. Considering the features of these biobased lacquers, they can be potential materials for bisphenol A-free metal packaging.

Identification of Effector Metabolites Using Exometabolite Profiling of Diverse Microalgae.

ABSTRACTDissolved exometabolites mediate algal interactions in aquatic ecosystems, but microalgal exometabolomes remain understudied. We conducted an untargeted metabolomic analysis of nonpolar exometabolites exuded from four phylogenetically and ecologically diverse eukaryotic microalgal strains grown in the laboratory, freshwater Chlamydomonas reinhardtii, brackish Desmodesmus sp., marine Phaeodactylum tricornutum, and marine Microchloropsis salina, to identify released metabolites based on relative enrichment in the exometabolomes compared to cell pellet metabolomes. Exudates from the different taxa were distinct, but we did not observe clear phylogenetic patterns. We used feature-based molecular networking to explore the identities of these metabolites, revealing several distinct di- and tripeptides secreted by each of the algae, lumichrome, a compound that is known to be involved in plant growth and bacterial quorum sensing, and novel prostaglandin-like compounds. We further investigated the impacts of exogenous additions of eight compounds selected based on exometabolome enrichment on algal growth. Of these compounds, five (lumichrome, 5′-S-methyl-5′-thioadenosine, 17-phenyl trinor prostaglandin A2, dodecanedioic acid, and aleuritic acid) impacted growth in at least one of the algal cultures. Two of these compounds (dodecanedioic acid and aleuritic acid) produced contrasting results, increasing growth in some algae and decreasing growth in others. Together, our results reveal new groups of microalgal exometabolites, some of which could alter algal growth when provided exogenously, suggesting potential roles in allelopathy and algal interactions.IMPORTANCE Microalgae are responsible for nearly half of primary production on earth and play an important role in global biogeochemical cycling as well as in a range of industrial applications. Algal exometabolites are important mediators of algal-algal and algal-bacterial interactions that ultimately affect algal growth and physiology. In this study, we characterize exometabolomes across marine and freshwater algae to gain insights into the diverse metabolites they release into their environments (“exudates”). We observe that while phylogeny can play a role in exometabolome content, environmental conditions or habitat origin (freshwater versus marine) are also important. We also find that several of these compounds can influence algal growth (as measured by chlorophyll production) when provided exogenously, highlighting the importance of characterization of these novel compounds and their role in microalgal ecophysiology.

Equipments for Manufacturing Lac Based Value Added Products

Lac, a natural resin of insect origin, yields basically three useful materials i.e.resin, wax and dye and is an important source of livelihood for poor and tribal farmers in the lac growing regions. Lac growers harvest lac in form of lac stick and lac encrustations attached with sticks are then scraped which is known as sticklac. Sticklac contains impurities which need to be removed by converting sticklac in to seedlac through different unit operations under primary lac processing so that seedlac, a semi-refined product, can be further used in making lac based value added products i.e.shellac, button lac, bleached lac, aleuritic acid etc. Sticklac converted into seedlac can be stored like grain in jute/gunny bag or metal bin for longer period. Hence, lac grower can sell stored seedlac whenever they get remunerative price. Lac resin being natural, biodegradable and non-toxic, finds application in food, textile, furniture, electrical and pharmaceutical industries and provides immense employment opportunities. Regular demand for the materials derived from lac exists in the market due to global trend for use of natural products. Small scale lac processing unit can be established for conversion of sticklac in to seedlac in production catchment area at grower's level itself. Similarly, integrated small scale lac processing unit can also be utilized for conversion of sticklac in to seedlac with reduced man-power requirement and minimum drudgery. Equipments/machineries developed for manufacturing value added lac-based products may be encouraged in the country to reduce time of operation, drudgery and manpower requirement with enhanced capacity of value addition in lac and to promote entrepreneurship development which may further enhance employment generation. To ensure the quality of produce, traditional equipments/machineries needs replacement with new equipments/machineries made of food grade materials coupled with advanced automation system to the maximum possible extent. Value addition in lac could be promoted and migration of rural and tribal people to other states in search of employment could be minimized with adoption of improved equipment and machineries for value addition of lac at village level so that rural and tribal people may get remunerative price of their product. Hence, increase in sustainable livelihood of rural and tribal people might be possible with adoption of lac value addition sector

Elucidating esterification reaction during deposition of cutin monomers from classical molecular dynamics simulations.

The structural behavior of some cutin monomers, when deposited on mica support, was extensively investigated by our research group. However, other events, such as esterification reaction (ER), are still a way to explore. In this paper, we explore possible ER that could occur when these monomers adsorb on support. Although classical molecular dynamics simulations are not able to capture reactive effects, here, we show that they become valuable strategies to analyze the initial structural configurations to predict the most favorable reaction routes. Thus, when depositing aleuritic acid (ALE), it is observed that the loss of capacity to form self-assembled (SA) systems favors different routes to occur ER. In pure ALE bilayers systems, an ER is given exclusively through the -COOH and primary -OH groups. In pure ALE monolayers systems, the ER does not happen when the system is self-assembled. However, for disorganized systems, it is able to occur by two possible routes: -COOH and primary -OH (route 1) and -COOH and secondary -OH (route 2). When palmitic acid (PAL) is added in small quantities, ALE SAMs can now form an ER. In this case, ER occurs mostly through the -COOH and secondary -OH groups. However, when the presence of PAL is dominant, ER can occur with either of both possibilities, that is, routes 1 and 2. Graphical abstract.

Bio-Based Coatings for Food Metal Packaging Inspired in Biopolyester Plant Cutin.

Metals used for food canning such as aluminum (Al), chromium-coated tin-free steel (TFS) and electrochemically tin-plated steel (ETP) were coated with a 2–3-µm-thick layer of polyaleuritate, the polyester resulting from the self-esterification of naturally-occurring 9,10,16-trihydroxyhexadecanoic (aleuritic) acid. The kinetic of the esterification was studied by FTIR spectroscopy; additionally, the catalytic activity of the surface layer of chromium oxide on TFS and, in particular, of tin oxide on ETP, was established. The texture, gloss and wettability of coatings were characterized by AFM, UV-Vis total reflectance and static water contact angle (WCA) measurements. The resistance of the coatings to solvents was also determined and related to the fraction of unreacted polyhydroxyacid. The occurrence of an oxidative diol cleavage reaction upon preparation in air induced a structural modification of the polyaleuritate layer and conferred upon it thermal stability and resistance to solvents. The promoting effect of the tin oxide layer in such an oxidative cleavage process fosters the potential of this methodology for the design of effective long-chain polyhydroxyester coatings on ETP.

Insoluble and Thermostable Polyhydroxyesters From a Renewable Natural Occurring Polyhydroxylated Fatty Acid.

To explore the potential of long chain polyhydroxyalkanoates as non-toxic food packaging materials, the characterization of polyesters prepared from a natural occurring polyhydroxylated C16 carboxylic acid (9,10,16-trihydroxyhexadecanoic or aleuritic acid) has been addressed. Such monomer has been selected to elucidate the reactivity of primary and secondary hydroxyl groups and their contribution to the structure and properties of the polyester. Resulting polyaleuritate films have been produced using an open mold in one-step, solvent-free self-polycondensation in melt state and directly in air to evaluate the effect of oxygen in their final physical and chemical properties. These polymers are amorphous, insoluble, and thermostable, being therefore suitable for solvent, and heat resistant barrier materials. Structurally, most of primary hydroxyls are involved in ester bonds, but there is some branching arising from the partial participation of secondary O-H groups. The oxidative cleavage of the vicinal diol moiety and a subsequent secondary esterification had a noticeable effect on the amorphization and stiffening of the polyester by branching and densification of the ester bond network. A derivation of such structural modification was the surface compaction and the reduction of permeability to water molecules. The addition of Ti(OiPr)4 as a catalyst had a moderate effect, likely because of a poor diffusion within the melt, but noticeably accelerated both the secondary esterification and the oxidative processes. Primary esterification was a high conversion bulk reaction while oxidation and secondary esterification was restricted to nearby regions of the air exposed side of cast films. The reason was a progressive hindering of oxygen diffusion as the reaction progresses and a self-regulation of the altered layer growth. Despite such a reduced extent, the oxidized layer noticeably increased the UV-vis light blockage capacity. In general, characterized physical properties suggest a high potential of these polyaleuritate polyesters as food preserving materials.

Preparation of novel mcl-PHA by green synthesis: influence of active small molecule via esterification effect on side chain

Microbial production of polyhydroxyalkanoic acid (PHA) with customized features has been attempted by humans through metabolic engineering. However, few studies have explored the green chemical synthesis of customized PHA using hydroxy fatty acids. In the present study, new mcl-PHA having C16-co-C16, blocked by esterification of hydroxy groups in the side chain, was synthesized by melt polycondensation using aleuritic acid (9, 10, 16-trihydroxyhexadecanoic acid) and lactic acid as long-chain fatty acid monomers and active blocking molecule, respectively. The results showed that when the two monomers reacted at 150 °C for 24 h, the properties of PHA were largely retained, along with free hydroxyl groups as much as possible. Comparison of the effect of different ratios of active small molecule (lactic acid) on the properties of new mcl-PHA revealed that copolymerization mainly happened between the long-chain monomers, and lactic acid served as a blocker by esterification in the side chain on the hydroxy groups of mcl-PHA. Further, the properties of side chain-esterified mcl-PHA (SCE-mcl-PHA) changed from rigid to soft with increasing ratio of active lactic acid monomer. The tensile strength of mcl-PHA was similar to that of commercially available products PLA and PHBV. The mechanical properties of SCE-mcl-PHA significantly changed by adding only 5 wt% lactic acid monomer. Besides, the cell proliferation analysis showed that the new PHA had minimum cytotoxicity, which was close to PLA and PHBV. Therefore, these new mcl-PHA and SCE-mcl-PHA have great potential for application in food, medicine, cosmetics, and other fields, and hence require further investigation.

Sustainable Electronics Based on Crop Plant Extracts and Graphene: A “Bioadvantaged” Approach

AbstractIn today's fast‐paced and well‐connected world, consumer electronics are evolving rapidly. As a result, the amount of discarded electronic devices is becoming a major health and environmental concern. The rapid expansion of flexible electronics has the potential to transform consumer electronic devices from rigid phones and tablets to robust wearable devices. This means increased use of plastics in consumer electronics and the potential to generate more persistent plastic waste for the environment. Hence, today, the need for flexible biodegradable electronics is at the forefront of minimizing the mounting pile of global electronic waste. A “bioadvantaged” approach to develop a biodegradable, flexible, and application‐adaptable electronic components based on crop components and graphene is reported. More specifically, by combining zein, a corn‐derived protein, and aleuritic acid, a major monomer of tomato cuticles and sheellac, along with graphene, biocomposite conductors having low electrical resistance (≈10 Ω sq−1) with exceptional mechanical and fatigue resilience are fabricated. Further, a number of high‐performance electronic applications, such as THz electromagnetic shielding, flexible GHz antenna construction, and flexible solar cell electrode, are demonstrated. Excellent performance results are measured from each application comparable to conventional nondegrading counterparts, thus paving the way for the concept of “plant‐e‐tronics” towards sustainability.

Cellulose-polyhydroxylated fatty acid ester-based bioplastics with tuning properties: Acylation via a mixed anhydride system

The synthesis of microcrystalline cellulose (MCC) and 9,10,16-hydroxyhexadecanoic (aleuritic) acid ester-based bioplastics was investigated through acylation in a mixed anhydride (trifluoroacetic acid (TFA)/trifluoroacetic acid anhydride (TFAA)), chloroform co-solvent system. The effects of chemical interactions and the molar ratio of aleuritic acid to the anhydroglucose unit (AGU) of cellulose were investigated. The degree of substitution (DS) of new polymers were characterized by two-dimensional solution-state NMR and ranged from 0.51 to 2.60. The chemical analysis by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) confirmed the presence of aleuritate groups in the structure induces the formation of new H-bond networks. The tensile analysis and the contact angle measurement confirmed the ductile behavior and the hydrophobicity of the prepared bioplastics. By increasing the aleuritate amounts, the glass transition temperature decreased and the solubility of bioplastic films in most common solvents was improved. Furthermore, this new polymer exhibits similar properties compared to commercial cellulose derivatives.

Laser-induced fabrication of gold nanoparticles on shellac-driven peptide nanostructures

This study demonstrates the synthesis of a new class of peptide amphiphiles derived from aleuritic acid. The aleuritic acid was extracted and purified from the natural source shellac, which was later conjugated with tryptophan, leading to a new class of very short peptide amphiphiles. The self-assembling behavior of this compound was studied using spectroscopic and microscopic tools. This shellac-driven peptide was further used to cultivate gold nanoparticles (AuNPs) with the help of continuous wave (CW) laser light, where the AuNPs were encapsulated by peptide nanostructures. Laser irradiation caused nanoscopically confined heating in the AuNPs-peptide hybrid nanostructures. Such confined heating is mainly the result of scattering and simultaneous absorption of subwavelength power which is subjected to enhanced plasmonic resonances of the metal nanostructures. Hence, the generated heat power/photothermal effect of these AuNPs leads to disruption of the AuNP–peptide hybrids. Such light-induced prototype nano-structure hydrid devices have a wide range of thermal-plasmonic applications in the morphological modification of soft metal hybrid nanostructures for photothermal therapy and drug release.

All‐Natural Sustainable Packaging Materials Inspired by Plant Cuticles

New sustainable composite materials inspired by plant cuticles have been fabricated by impregnation of fibrous cellulose substrates with a naturally occurring polyhydroxylated fatty acid (9,10,16‐trihydroxypalmitic or aleuritic acid) and subsequent polymerization of the latter into polyaleuritate. A two‐step preparation method is used, comprising of spraying and hot‐pressing. The hot‐pressing temperature is critical for the extent of polymerization of polyaleuritate and its alteration allows fine tuning of the mechanical properties, opacity, wettability, and water adsorption of the developed composite materials. The cellulose substrate controls other characteristics such as water permeability and thermal conductivity. Addition of carnauba wax into the polyaleuritate matrix results in improvement of water and oxygen barrier properties. Best results in terms of mechanical resistivity, transparency, water resistance, and low values of oxygen permeability are obtained for samples fabricated using hot‐pressing temperature of 200 °C and with a final formulation of 80.6% of cellulose, 17.7% of aleuritic acid, and 1.7% of carnauba wax. Comparison of the composite properties with common plastics confirms that these plant cuticle‐like materials can become promising alternatives to petroleum‐based macromolecules for packaging applications.

Biodegradable polyester films from renewable aleuritic acid: surface modifications induced by melt-polycondensation in air

Good water barrier properties and biocompatibility of long-chain biopolyesters like cutin and suberin have inspired the design of synthetic mimetic materials. Most of these biopolymers are made from esterified mid-chain functionalized ω-long chain hydroxyacids. Aleuritic (9,10,16-trihydroxypalmitic) acid is such a polyhydroxylated fatty acid and is also the major constituent of natural lac resin, a relatively abundant and renewable resource. Insoluble and thermostable films have been prepared from aleuritic acid by melt-condensation polymerization in air without catalysts, an easy and attractive procedure for large scale production. Intended to be used as a protective coating, the barrier's performance is expected to be conditioned by physical and chemical modifications induced by oxygen on the air-exposed side. Hence, the chemical composition, texture, mechanical behavior, hydrophobicity, chemical resistance and biodegradation of the film surface have been studied by attenuated total reflection–Fourier transform infrared spectroscopy (ATR–FTIR), atomic force microscopy (AFM), nanoindentation and water contact angle (WCA). It has been demonstrated that the occurrence of side oxidation reactions conditions the surface physical and chemical properties of these polyhydroxyester films. Additionally, the addition of palmitic acid to reduce the presence of hydrophilic free hydroxyl groups was found to have a strong influence on these parameters.