Production of Steryl Esters from Vegetable Oil Deodorizer Distillates by Enzymatic Esterification

A review of synthesis of esters with aromatic, emulsifying, and lubricant properties by biotransformation using lipases

The esterification reactions catalyzed by lipases are among the most significant biochemical processes of industrial relevance. The lipases have the function of versatility by catalyzing a diversity of reactions with extreme ease, obtaining quality products with high yield. Therefore, enzyme-catalyzed esterification has gained increasing attention in many applications, due to the importance of derived products. More specifically, lipase-catalyzed esterification reactions have attracted interest in research over the past decade, due to the increased use of organic esters in the chemical and biotechnology industry. These esters can be obtained by three techniques: extraction from natural sources, chemical and enzymatic syntheses. Biotechnological processes have offered several advantages and are shown as a competitive alternative to chemical methods due to high catalytic efficiency, mild operating conditions, and selectivity of natural catalysts. These an industrial point of view, reactions catalyzed by enzymes are the most economical approach to achieve green products with no toxicity and no harm to human health. Thus, this review presents a descriptive evaluation of the trends and perspectives applied to enzymatic esterification, mainly for the synthesis of esters with different properties, such as aromatics, emulsifiers, and lubricants using the esterification process. An emphasis is given to essential factors, which affect the lipase-catalyzed esterification reaction. In which, the parameters dependent on the lipase source, a form of the biocatalyst (free or immobilized), the polarity of the reaction medium, the molar ratio between alcohol and acid, among other variables, are also discussed. This article is protected by copyright. All rights reserved.

Integrated Utilization Strategy for Soybean Oil Deodorizer Distillate: Synergically Synthesizing Biodiesel and Recovering Bioactive Compounds by a Combined Enzymatic Process and Molecular Distillation

Soybean oil deodorizer distillate (SODD) is well recognized as a good source of both biodiesel and high-value bioactive compounds of tocopherols, squalene, and phytosterols. To achieve a one-step synthesis of biodiesel and recovery of bioactive compounds from SODD, four commercial immobilized enzymes (Novozym 435, Lipozyme TLIM, Lipozyme RMIM, and Lipozyme RM) and one self-prepared immobilized lipase MAS1-H108A were compared. The results showed that immobilized lipase MAS1-H108A due to the better methanol tolerance and higher catalytic activity gave the highest biodiesel yield of 97.08% under the optimized conditions: molar ratio of 1:2 (oil/methanol), temperature of 35 °C, and enzyme loading of 35 U/g SODD, even after 10 persistent cycles without significant decrease of activity. Simultaneously, there was no loss of tocopherols and squalene in SODD during the enzymatic reaction. Pure biodiesel (characterized by fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR)) and a high concentration of bioactive compounds could be successfully separated by molecular distillation at 100 °C. In a word, this work provides an interesting idea to achieve environmentally friendly treatment of SODD by combining an enzymatic process and molecular distillation, and it is suitable for industrial production.

Advances in various techniques for isolation and purification of sterols

Plants consist of triterpenoids such as phytosterols (PT) (C₂₉H₅₀O) with steroidal nuclei, including sitosterol, stigmasterol, brassicasterol and campesterol. They are hydrophobic but soluble in alcohol and other organic solvents and are isolated from industrial waste deodorizer distillates of various edible oil industries. They exist as free PT or their ester derivatives in soybean, rice, wheat, oat, cottonseed and corn fiber, and other cereals and grains. Conventional isolation techniques such as solvent extraction, distillation, evaporative fractionation, saponification and chemical esterification are employed for isolation and purification of PT. The present article reviews the various advanced separation techniques like solvent crystallization, supercritical fluid extraction, high speed counter-current chromatography and enzymatic process as strategic methods to isolate and purify sterols.

Mass Spectrometric Approaches for the Analysis of Phytosterols in Biological Samples

Plant sterols (phytosterols) are important structural components of plant cellular membranes, and they play a major role during development and metabolism. They have health-associated benefits, especially in lowering blood cholesterol levels. Because of their many health claims, there is a growing interest in their analysis. Although various analytical strategies have been employed in analyzing phytosterols, chromatography linked to mass spectrometry (MS) is superior due to its sensitivity. Furthermore, specificity and selectivity are enhanced by utilizing tandem mass spectrometry (MS/MS). This article reviews the various mass spectrometric strategies used for the analysis of phytosterols. It highlights the applications and limitations associated with each MS strategy in various sample matrixes such as plant, human, animal, food, and dietary supplements. GC-MS was historically the method of choice for analysis; however, the derivatization step rendered it tedious and time-consuming. On the other hand, liquid chromatography coupled to MS (LC-MS) simplifies the analysis. Many ionization techniques have been used, namely, electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI), and atmospheric pressure photoionization (APPI). APCI showed superiority in terms of ion intensity and consistency in ion formation, primarily forming [M + H - H₂O]⁺ ions rather than [M + H]⁺. In addition, matrix assisted laser desorption ionization (MALDI) as well as ambient mass spectrometry such as direct analysis in real time (DART) have also been evaluated.

Valorization of fatty acids-containing wastes and byproducts into short- and medium-chain length polyhydroxyalkanoates

Olive oil distillate (OOD), biodiesel fatty acids-byproduct (FAB) and used cooking oil (UCO) were tested as inexpensive carbon sources for the production of polyhydroxyalkanoates (PHA) with different composition using twelve bacterial strains. OOD and FAB were exploited for the first time as alternative substrates for PHA production. UCO, OOD and FAB were used by Cupriavidus necator and Pseudomonas oleovorans to synthesize the homopolymer poly-3-hydroxybutyrate, while Pseudomonas resinovorans and Pseudomonas citronellolis produced mcl-PHA polymers mainly composed of hydroxyoctanoate and hydroxydecanoate monomers. The highest polymer content in the biomass was obtained for C. necator (62 wt.%) cultivated on OOD. Relatively high mcl-PHA content (28-31 wt.%) was reached by P. resinovorans cultivated in OOD. This study shows, for the first time, that OOD is a promising substrate for PHA production since it gives high polymer yields and allows for the synthesis of different polymers (scl- or mcl-PHA) by selection of the adequate strains.

Lipase-mediated synthesis of water-soluble plant stanol derivatives in tert-butanol

The effects of solvents with different log P values, and of lipases on the synthesis of water-soluble plant stanol derivatives were investigated. Results showed that conversion in solvents with log P<0.37 was mainly controlled by the hydrophobicity of the solvent and subsequent complete or partial deactivation of the enzyme. The solubility of substrate was the leading factor for the conversion in solvents with log P>0.37. Lipozyme RM IM and tert-butanol was the most suitable biocatalyst and solvent, respectively. The highest yield (>51%) of plant stanyl sorbitol succinate was obtained under the selected conditions: 50 μmol/mL plant stanyl hemisuccinate, 1:3 molar ratio of plant stanyl hemisuccinate to d-sorbitol, 80 mg/mL 3 Å molecular sieves and 100mg/mL Lipozyme RM IM in tert-butanol, 150 r/min and 55 °C. Fourier transform infrared spectroscopy, mass spectroscopy and nuclear magnetic resonance spectroscopy were adopted to determine the structure of product, suggesting that water-soluble plant stanol derivatives were successfully synthesized.