Castor Oil: Properties, Uses, and Optimization of Processing Parameters in Commercial Production

Green Process without Thinning Agents for Preparing Sebacic Acid via Solid-Phase Cleavage

A green and environmentally friendly route of no thinning agent was designed to prepare sebacic acid. Sodium ricinoleate was selected as the raw material to carry out solid-phase cleavage in a tubular furnace. The reaction parameters including catalyst, ratio of sodium ricinoleate/KOH, reaction time, reaction temperature, and absolute pressure were optimized to obtain a high yield of sebacic acid. A satisfactory yield (70.2%) of sebacic acid was received in the presence of 1% catalyst (Fe₂O₃) by weight (w/w), with 5:4 (w/w) ratio of sodium ricinoleate/KOH at 543 K under the absolute pressure of 0.09 MPa in 60 min. Sebacic acid was identified by gas chromatography analysis, and the purity (98.1%) of the product was further assessed by its melting point (306.3 K). Alkaline enhancement generates a better cracking effect. The yield of sebacic acid can be improved by a certain absolute pressure as a result of avoiding oxidation of sodium ricinoleate as well as reducing the residence time of hydrogen.

Metabolic engineering of Ashbya gossypii for deciphering the de novo biosynthesis of γ-lactones

Background

Lactones are highly valuable cyclic esters of hydroxy fatty acids that find application as pure fragrances or as building blocks of speciality chemicals. While chemical synthesis often leads to undesired racemic mixtures, microbial production allows obtaining optically pure lactones. The production of a specific lactone by biotransformation depends on the supply of the corresponding hydroxy fatty acid, which has economic and industrial value similar to γ-lactones. Hence, the identification and exploration of microorganisms with the rare natural ability for de novo biosynthesis of lactones will contribute to the long-term sustainability of microbial production. In this study, the innate ability of Ashbya gossypii for de novo production of γ-lactones from glucose was evaluated and improved.

Results

Characterization of the volatile organic compounds produced by nine strains of this industrial filamentous fungus in glucose-based medium revealed the noteworthy presence of seven chemically different γ-lactones. To decipher and understand the de novo biosynthesis of γ-lactones from glucose, we developed metabolic engineering strategies focused on the fatty acid biosynthesis and the β-oxidation pathways. Overexpression of AgDES589, encoding a desaturase for the conversion of oleic acid (C18:1) into linoleic acid (C18:2), and deletion of AgELO624, which encodes an elongase that catalyses the formation of C20:0 and C22:0 fatty acids, greatly increased the production of γ-lactones (up to 6.4-fold; (7.6 ± 0.8) × 10³ µg/g_{Cell Dry Weight}). Further substitution of AgPOX1, encoding the exclusive acyl-CoA oxidase in A. gossypii, by a codon-optimized POX2 gene from Yarrowia lipolytica, which encodes a specific long chain acyl-CoA oxidase, fine-tuned the biosynthesis of γ-decalactone to a relative production of more than 99%.

Conclusions

This study demonstrates the potential of A. gossypii as a model and future platform for de novo biosynthesis of γ-lactones. By means of metabolic engineering, key enzymatic steps involved in their production were elucidated. Moreover, the combinatorial metabolic engineering strategies developed resulted in improved de novo biosynthesis of γ-decalactone. In sum, these proof-of-concept data revealed yet unknown metabolic and genetic determinants important for the future exploration of the de novo production of γ-lactones as an alternative to biotransformation processes.

Electronic supplementary material

The online version of this article (10.1186/s12934-019-1113-1) contains supplementary material, which is available to authorized users.

Biological Toxins as the Potential Tools for Bioterrorism

Biological toxins are a heterogeneous group produced by living organisms. One dictionary defines them as "Chemicals produced by living organisms that have toxic properties for another organism". Toxins are very attractive to terrorists for use in acts of bioterrorism. The first reason is that many biological toxins can be obtained very easily. Simple bacterial culturing systems and extraction equipment dedicated to plant toxins are cheap and easily available, and can even be constructed at home. Many toxins affect the nervous systems of mammals by interfering with the transmission of nerve impulses, which gives them their high potential in bioterrorist attacks. Others are responsible for blockage of main cellular metabolism, causing cellular death. Moreover, most toxins act very quickly and are lethal in low doses (LD50 < 25 mg/kg), which are very often lower than chemical warfare agents. For these reasons we decided to prepare this review paper which main aim is to present the high potential of biological toxins as factors of bioterrorism describing the general characteristics, mechanisms of action and treatment of most potent biological toxins. In this paper we focused on six most danger toxins: botulinum toxin, staphylococcal enterotoxins, Clostridium perfringens toxins, ricin, abrin and T-2 toxin. We hope that this paper will help in understanding the problem of availability and potential of biological toxins.

Synthesis, Performance and Emission Quality Assessment of Ecodiesel from Castor Oil in Diesel/Biofuel/Alcohol Triple Blends in a Diesel Engine

This research aims to promote the use of second-generation biofuels based mainly on Castor oil, which is not adequate for food use, and Sunflower oil as a standard reference for recycled oils. They have been applied in the production of Ecodiesel, a biofuel that integrates glycerol as monoglyceride, employing sodium methoxide as homogeneous catalyst and ethanol as solvent, but operating in milder conditions than in the synthesis of conventional biodiesel in order to obtain a kinetic control of the selective transesterification. The behavior of biofuels has been evaluated in a conventional diesel engine, operating as an electricity generator. The contamination degree was also evaluated from the opacity values of the generated smokes. The different biofuels here studied have practically no differences in the behavior with respect to the power generated, although a small increase in the fuel consumption was obtained in some cases. However, with the biofuels employed, a significant reduction, up to 40%, in the emission of pollutants is obtained, mainly with the blend diesel/castor oil/alcohol. Besides, it is found that pure Castor oil can be employed directly as biofuel in triple blends diesel/biofuel/alcohol, exhibiting results that are very close to those obtained using biodiesel or Ecodiesel.

In-situ reactive extraction of castor seeds for biodiesel production using the coordinated ultrasound - microwave irradiation: Process optimization and kinetic modeling

The present study demonstrates innovative and industrially viable in-situ biodiesel production process using coordinated ultrasound-microwave reactor. Reactive extraction process has been carried out by mixing grinded castor seeds with methanol in the presence of base catalyst (KOH). Response surface methodology coupled with central composite design has been applied for process optimization to achieve maximum yield. The result shows that maximum biodiesel yield of 93.5 ± 0.76% was obtained under favorable conditions of: molar ratio (350:1), catalyst (w/w) (1.74%), reaction temperature (43 °C) and reaction time (30 min). Regression equation obtained for the model having (R²), and (R²_adj) equal to 0.9737 and 0.9507 respectively shows goodness of fit. First time reaction kinetics as well as oil extraction kinetics studies have been performed on coordinated ultrasound-microwave reactor. Assuming pseudo first order reaction activation energy was found to be 28.27 kJ·mol^-1 and activation energy for oil extraction was observed to be 9.11 kJ mol^-1. Estimated activation energy for the reaction kinetics and extraction kinetics was reduced by 27%, reaction rate constants were eight to ten times higher and diffusion coefficient was found to be two times higher in case of hybrid system as compared to conventional mechanical stirring technique. Estimated thermo-physical properties of biodiesel were found in agreement with ASTM and DIN standards in comparison to gasoline diesel.

Ultrasonication-Assisted and Benzimidazolium-Based Brønsted Acid Ionic Liquid-Catalyzed Transesterification of Castor Oil

In this investigation, we report the synthesis of biodiesel using benzimidazolium-based brønsted acid ionic liquid (BBAIL) catalyst under the influence of ultrasonication. The prepared BBAIL catalyst was characterized by Fourier transform infrared and NMR spectroscopy techniques, and its acidity was determined by the Hammett method with 4-nitroaniline as the indicator. Ultrasonicator horn (22 kHz, 500 W) was used in this work with an on-off cycle of 50-20 s at 70% amplitude. The highest biodiesel yield of 96% was achieved by ultrasonication when 1:10 molar ratio of castor oil to methyl alcohol was used at 50 °C temperature with 9 mol % of the catalyst in just 90 min, which is about 10 times lesser than the process without ultrasonication. At similar conditions, 96% biodiesel yield was obtained in 14 h without ultrasonication. In summary, ultrasonication proved to be an efficient way to improve biodiesel synthesis in less time and BBAIL showed excellent activity toward the conversion of glycerides to synthesize biodiesel. Other important highlights are easy separation of the catalyst and recyclability up to three cycles with small decrease in its activity.

Accidental poisoning by castor bean (Ricinus communis) cake in horses

Abstract: Ricinus communis is a shrub of the family Euphorbiaceae popularly known in Brazil as “mamona” or “carrapateira”. It is an oleaginous plant whose seeds have been used mainly in biodiesel production. Plant seed oil can be extracted mechanically or using solvents, generating castor bean cake and castor bean meal as by-products, respectively. Accidental ingestion of these by-products can cause poisoning in animals and humans, characterized by digestive signs resulting from the presence of a toxalbumin called ricin. Seed toxicity varies among animal species; in horses, the lethal dose of seeds is 0.1 g/kg of body weight. The literature presents plenty of studies addressing poisoning by R. communis in different animal species and in humans; however, reports are scarce and little information is available on the pathological aspects of poisoning regarding equines. Therefore, the present study aimed to describe the epidemiological, clinical and pathological aspects observed in an outbreak of accidental poisoning with castor bean cake in horses. The equines were supplemented with palm kernel (Elaeis guianeesis) cake; however, in the purchase of a new batch, there was an error in the order, and castor bean cake was requested instead. Four horses that received castor bean cake presented clinical signs indicative of colic, which started about 21 hours after administration. Three of these horses died, with clinical evolution from 2 to 4.5 hours; the other animal was treated with intravenous fluid and antibiotic therapy and non-steroidal anti-inflammatory drugs and recovered after five days. In the necropsy of two of these horses, the main lesions were found in the small intestine, where mucosae with pronounced redness and covered with a thin layer of yellow fibrous material were observed. In the intestinal lumen, there was a large amount of bloody liquid. The stomach was full, and dark lumps similar to crushed castor bean seeds were observed in the contents. The adrenal glands of both horses presented congestion and hemorrhage in the cortex. In microscopy, the main lesion was an acute, diffuse and accentuated fibrin-necrotic enteropathy affecting the jejunum. The diagnosis of castor bean cake poisoning was based on the circumstantial evidence of by-product consumption supported by clinical and pathological aspects. The results indicate that castor bean cake commercially available as fertilizer is extremely toxic when ingested, and there is a need for appropriate detoxification or labeling informing of its toxicity.

Dangerous plants in dermatology: Legal and controlled

The plant and mushroom kingdoms have species used for intoxication, inebriation, or recreation. Some of these species are toxic. Given that many of these plants or substances are illegal and have histories of abuse, much of the research regarding therapeutic application is based on basic science, animal studies, and traditional use. This review examines Cannabis, Euphorbia, Ricinus, Podophyllum, Veratrum, mushrooms, and nightshades, along with resveratrol and cocaine as they relate to dermatology.

New Bacterial Phytase through Metagenomic Prospection

Alkaline phytases from uncultured microorganisms, which hydrolyze phytate to less phosphorylated myo-inositols and inorganic phosphate, have great potential as additives in agricultural industry. The development of metagenomics has stemmed from the ineluctable evidence that as-yet-uncultured microorganisms represent the vast majority of organisms in most environments on earth. In this study, a gene encoding a phytase was cloned from red rice crop residues and castor bean cake using a metagenomics strategy. The amino acid identity between this gene and its closest published counterparts is lower than 60%. The phytase was named PhyRC001 and was biochemically characterized. This recombinant protein showed activity on sodium phytate, indicating that PhyRC001 is a hydrolase enzyme. The enzymatic activity was optimal at a pH of 7.0 and at a temperature of 35 °C. β-propeller phytases possess great potential as feed additives because they are the only type of phytase with high activity at neutral pH. Therefore, to explore and exploit the underlying mechanism for β-propeller phytase functions could be of great benefit to biotechnology.

Bio-detoxification of ricin in castor bean (Ricinus communis L.) seeds

Ricin is a highly toxic ribosome-inactivating lectin occurring in the seeds of castor bean (Ricinus communis L.). Castor bean grows throughout tropical and sub-tropical regions and is a very important crop due to its high seed content of ricinoleic acid, an unusual fatty acid, which has several industrial applications. However, due to the presence of the toxin, castor bean can cause death after the exposure of animals to low doses of ricin through skin contact, injection, inhalation or oral routes. Aiming to generate a detoxified genotype, we explored the RNAi concept in order to silence the ricin coding genes in the endosperm of castor bean seeds. Results indicated that ricin genes were effectively silenced in genetically modified (GM) plants, and ricin proteins were not detected by ELISA. Hemagglutination activity was not observed with proteins isolated from GM seeds. In addition, we demonstrated that seed proteins from GM plants were not toxic to rat intestine epithelial cells or to Swiss Webster mice. After oil extraction, bio-detoxified castor bean cake, which is very rich in valuable proteins, can be used for animal feeding. Gene silencing would make castor bean cultivation safer for farmers, industrial workers and society.

Review: Metabolic engineering of unusual lipids in the synthetic biology era

The plant kingdom produces a variety of fatty acid structures, many of which possess functional groups useful for industrial applications. The species that produce these unusual fatty acids are often not suitable for large scale commercial production. The ability to create genetically modified plants, together with emerging synthetic biology approaches, offers the potential to develop alternative oil seed crops capable of producing high levels of modified lipids. In some cases, by combining genes from different species, non-natural lipids with a targeted structure can be conceived. However, the expression of the biosynthetic enzymes responsible for the synthesis of unusual fatty acids typically results in poor accumulation of the desired product. An improved understanding of fatty acid flux from synthesis to storage revealed that specialized enzymes are needed to traffic unusual fatty acids. Co-expression of some of these additional enzymes has incrementally increased the levels of unusual fatty acids in transgenic seeds. Understanding how the introduced pathways interact with the endogenous pathways will be important for further enhancing the levels of unusual fatty acids in transgenic plants. Eliminating endogenous activities, as well as segregating the different pathways, represent strategies to further increase accumulation of unusual lipids.