Highly efficient solvent-free synthesis of 1,3-diacylglycerols by lipase immobilised on nano-sized magnetite particles

Direct Chiral Supercritical Fluid Chromatography-Mass Spectrometry Analysis of Monoacylglycerol and Diacylglycerol Isomers for the Study of Lipase-Catalyzed Hydrolysis of Triacylglycerols

The fast and selective separation method of intact monoacylglycerol (MG) and diacylglycerol (DG) isomers using chiral supercritical fluid chromatography-mass spectrometry (SFC-MS) was developed and employed to study lipase selectivity in the hydrolysis of triacylglycerols (TGs). The synthesis of 28 enantiomerically pure MG and DG isomers was performed in the first stage using the most commonly occurring fatty acids in biological samples such as palmitic, stearic, oleic, linoleic, linolenic, arachidonic, and docosahexaenoic acids. To develop the SFC separation method, different chromatographic conditions such as column chemistry, mobile phase composition and gradient, flow rate, backpressure, and temperature were carefully assessed. Our SFC-MS method used a chiral column based on a tris(3,5-dimethylphenylcarbamate) derivative of amylose and neat methanol as a mobile phase modifier, which provides baseline separation of all the tested enantiomers in 5 min. This method was used to evaluate hydrolysis selectivity of lipases from porcine pancreas (PPL) and Pseudomonas fluorescens (PFL) using nine TGs differing in acyl chain length (14-22 carbon atoms) and number of double bonds (0-6) and three DG regioisomer/enantiomers as hydrolysis intermediate products. PFL exhibited preference of the fatty acyl hydrolysis from the sn-1 position of TG more pronounced for the substrates with long polyunsaturated acyls, while PPL did not show considerable stereoselectivity to TGs. Conversely, PPL preferred hydrolysis from the sn-1 position of prochiral sn-1,3-DG regioisomer, whereas PFL exhibited no preference. Both lipases showed selectivity for the hydrolysis of outer positions of DG enantiomers. The results show complex reaction kinetics of lipase-catalyzed hydrolysis given by different stereoselectivities for substrates.

Structure-guided preparation of fuctional oil rich in 1,3-diacylglycerols and linoleic acid from Camellia oil by combi-lipase

BACKGROUND

Diacylglycerol (DAG)-enriched oil has been attracting attention because of its nutritional benefits and biological functions, although the composition of its various free fatty acids (FFAs) and an unclear relationship between substrate and yield make it difficult to be identified and qualified with respect to its production. In the present study, linoleic acid-enriched diacylglycerol (LA-DAG) was synthesized and enriched from Camellia oil by the esterification process using the combi-lipase Lipozyme TL IM/RM IM system.

RESULTS

The relationship between FFA composition and DAG species productivity was revealed. The results showed that heterogeneous FFA with a major constituent (more than 50%) exhibited higher DAG productivity and inhibited triacylglycerol productivity compared to homogeneous constituents. Joint characterization by high-performance liquid chromatography-evaporative light scattering detection, gas chromatography-mass spectrometry and ultra-performance liquid chromatography-heated electrospray ionization-tandem mass spectrometry identified that DAG components contained dilinoleic acid acyl glyceride, linoleyl-oleyl glyceride and dioleic acid acyl glyceride in esterification products. Under the optimum conditions, 60.4% 1,3-DAG and 61.3% LA-DAG in the crude product at 1 h reaction were obtained, and further purified to 81.7% LA-DAG and 94.7% DAG via silica column chromatography.

CONCLUSION

The present study provides a guideline for the identification of DAG species, as well as a structure-guided preparation method of DAG-enriched oils via the cost-effective combi-lipase. © 2022 Society of Chemical Industry.

Biosynthesis and Bioapplications of Nanomaterials from Mushroom Products

The production of nanoparticles (NPs) from chemical and physical synthesis has ended due to the involvement of toxic byproducts and harsh analytical conditions. Innovation and research in nanoparticle synthesis are derived from biomaterials that have gained attention due to their novel features, such as ease of synthesis, low-cost, eco-friendly approach, and high water solubility. Nanoparticles obtained through macrofungi involve several mushroom species, i.e., Pleurotus spp., Ganoderma spp., Lentinus spp., and Agaricus bisporus. It is well-known that macrofungi possess high nutritional, antimicrobial, anti-cancerous, and immune-modulatory properties. Nanoparticle synthesis via medicinal and edible mushrooms is a striking research field, as macrofungi act as an eco-friendly biofilm that secretes essential enzymes to reduce metal ions. The mushroom-isolated nanoparticles exhibit longer shelf life, higher stability, and increased biological activities. The synthesis mechanisms are still unknown; evidence suggests that fungal flavones and reductases have a significant role. Several macrofungi have been utilized for metal synthesis (such as Ag, Au, Pt, Fe) and non-metal nanoparticles (Cd, Se, etc.). These nanoparticles have found significant applications in advancing industrial and bio-medical ventures. A complete understanding of the synthesis mechanism will help optimize the synthesis protocols and control the shape and size of nanoparticles. This review highlights various aspects of NP production via mushrooms, including its synthesis from mycelium and the fruiting body of macrofungi. Also, we discuss the applications of different technologies in NP high-scale production via mushrooms.

Synthesis of cross-linked magnetic chitosan beads immobilised with bacteria for aerobic biodegrading benzophenone-type UV filter

Bacterial immobilisation is a technique by which bacteria are embedded into or adsorbed onto a carrier material thereby increasing bacterial tolerance to harsh environments. This technique can be used to enhance bacterial activity and to degrade pollutants. Immobilised bacterial beads that contain nanomagnetic particles allow bead recycling and reuse. In this study, our objective was to produce cross-linked nanomagnetic chitosan beads (MCBs) for the biodegradation of benzophenone-type UV filter chemicals such as 2,4-dihydroxybenzophenone (BP-1) and oxybenzone (BP-3). We found that the optimal concentration for creating these MCBs to be 1.2% by weight chitosan and 10% by weight nano-magnetite. We selected and isolated six benzophenone-n (BPs)-biodegrading bacteria identified to be various Pseudomonas spp., a Gordonia sp., and Rhodococcus zopfii; these were used to create MCBs that were able to effectively biodegrade BP-1 or BP-3 as a sole carbon source. Both BPs were effectively biodegraded and mineralised over 8 days in the presence of the selected MCB-immobilised bacterial strains. The highest pseudo-first-order constant rates for BP biodegradation were 8.7 × 10^-3 h^-1 for BP-1 (strain BP1-D) and 1.02 × 10^-3 h^-1 for BP-3 (strain BP3-1). The mechanical strength of the MCBs was measured to be above 90% based on recovered weight. The MCBs released their bacteria at rates in the range of 10⁴-10⁵ CFU/day. We also determined the pathway through which the BPs were being aerobically biodegraded based on the GC/MS profiles of the intermediates. Our findings provide a novel strategy for treating BPs via the use of reusable and recyclable MCBs that are cheap, easy and fast to synthesise.

Controllably crosslinked dual enzymes enabled by genetic-encoded non-standard amino acid for efficiently enantioselective hydrogenation

In traditional method for preparing crosslinked enzymes aggregates using glutaraldehyde, random linkage is inevitable, which often destroys the enzyme active sites and severely decreases the activity. To address this issue, using genetic encode expanding, nonstandard amino acids (NSAAs) were inserted into enzyme proteins at the preselected sites for crosslinking. When aldehyde ketone reductase (AKR), alcohol dehydrogenase (ADH) and glucose dehydrogenase (GDH) were utilized as model enzymes, their mutants containing p-azido-L-phenylalanine were bio-orthogonally crosslinked with diyne to form crosslinked dual enzymes (CLDEs) acting as a cascade biological oxidation and reduction system. Then, the resultant self-purified CLDEs were characterized using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS), scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM), etc. In the asymmetric synthesis of (S)-1-(2,6-dichloro-3-fluorophenyl) ethanol using CLDEs, high product yield (76.08%), ee value (99.99%) and reuse stability were achieved. The yield and ee value were 12.05 times and 1.39 times higher than those using traditional crosslinked enzyme aggregates, respectively. Thus, controllable insertion NSAAs in number and location can engender reasonable linkage and metal-free self-purification for target enzyme proteins. This facile and sustainable method could be further expanded to other dual and multienzyme systems for cascade biocatalysis.

Potentialities of bioinspired metal and metal oxide nanoparticles in biomedical sciences

To date, various reports have shown that metallic gold bhasma at the nanoscale form was used as medicine as early as 2500 B.C. in India, China, and Egypt. Owing to their unique physicochemical, biological, and electronic properties, they have broad utilities in energy, environment, agriculture and more recently, the biomedical field. The biomedical domain has been used in drug delivery, imaging, diagnostics, therapeutics, and biosensing applications. In this review, we will discuss and highlight the increasing control over metal and metal oxide nanoparticle structures as smart nanomaterials utilized in the biomedical domain to advance the role of biosynthesized nanoparticles for improving human health through wide applications in the targeted drug delivery, controlled release drug delivery, wound dressing, tissue scaffolding, and medical implants. In addition, we have discussed concerns related to the role of these types of nanoparticles as an anti-viral agent by majorly highlighting the ways to combat the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) pandemic, along with their prospects.

Evaluation of the Candida sp. 99-125 Lipase Positional Selectivity for 1,3-Diolein Synthesis

In this study, comparative experiments were carried out to investigate the positional selectivity of Candida sp. 99-125 lipase in preparing 1,3-diolein by using medium engineering strategy. The results indicated that the diolein yield was markedly enhanced from 56.5% to 86.7% with increasing log⁡P values of the solvents, while the selectivity of the examined lipase for the sn-1 over the sn-2 hydroxyl of glycerol was decreased, thus leading to a reduced 1,3-diolein to 1,2-diolein ratio. To evaluate the possibility of industrial enzymatic production of 1,3-diolein, larger-scale experiments were assessed. After being used repeatedly for eight batches, the diolein content reached 95.1%, while the 1,3-diolein to 1,2-diolein ratio was 7:1 following purification. Results of the kg level experiments significantly demonstrated the practicability of the enzymatic process and the efficiency of the purification strategy for the product.

Lipase-catalyzed Production and Purification of Palm Esters Using Stirred Tank Reactors (STR)

Lipase-catalyzed production of palm esters was performed via alcoholysis of palm oil and oleyl alcohol in solvent and solvent-free systems using a 2 L stirred tank reactor (STR). Two immobilized lipases were tested and Lipozyme RM IM exhibited superior performance in both reaction systems. Reusability studies of the enzymes in a solvent-free system also demonstrated the high stability of Lipozyme RM IM as shown by its ability to yield more than 70% palm esters with up to 19 cycles of reusing the same enzymes. Modification of the enzyme washing process improved the stability of Lipozyme TL IM in a solvent system as demonstrated by maintaining 65% yield after 5 times of repeated enzyme use. The scale up process for both lipases was conducted in the presence of solvents by using the impeller tip speed approach. Lipozyme RM IM-catalyzed reaction in a 15 L STR produced 85.7% yield and there was a significant drop to 60.7% in the 300 L STR, whereas Lipozyme TL IM had a lower yield (65%) when the reaction volume was increased to 15 L. The low yields could be due to the accumulation of enzymes at the bottom of the vessel. Purification of palm esters via solvent-solvent extraction revealed that more than 90% of oleyl alcohol was extracted after the third extraction cycle at 150 rpm impeller speed with reduced palm esters: ethanol ratio (v/v) from 1:4 to 1:3.

Enhancing the thermostability of Rhizopus oryzae lipase by combined mutation of hot-spots and engineering a disulfide bond

Rhizopus oryzae lipase (ROL) is important because of its extreme sn-1,3-regioselectivity, but it shows poor thermostability, which severely restricts its application. In this work, the thermostability of ROL was greatly enhanced by rational design. First, several sites that may affect the thermostability of ROL were identified by multiple-sequence alignment. The half-lives of mutants V209L and D262G at 55 °C were about 4.38- and 4.2-times those of the wild-type, respectively. Then, a disulfide bond was introduced between positions 190 and 238 based on the prediction of Disulfide by Design 2, which greatly improved the thermostability of the protein. The activity of variant E190C/E238C retained about 58.2% after incubation at 55 °C for 720 min, whereas the half-life of wild type ROL was only about 11.7 min. On the basis of the results obtained by the two methods, we carried out a combined mutation. Quadruple mutant V209L/D262G/E190C/E238C was constructed and the thermostability was improved even further. The half-lives at 55 °C and 65 °C were 102.5- and 20-times those of the wild-type ROL. This improvement in thermostability will give ROL wider industrial applicability, especially in the preparation of structured lipids.

Magnetic nanoparticles: a versatile carrier for enzymes in bio-processing sectors

Many industrial processes experience the advantages of enzymes which evolved the demand for enzymatic technologies. The enzyme immobilisation technology using different carriers has trustworthy applications in industrial biotechnology as these techniques encompass varied advantages such as enhanced stability, activity along with reusability. Immobilisation onto nanomaterial is highly favourable as it includes almost all aspects of science. Among the various techniques of immobilisation, the uses of nanoparticles are remarkably well perceived as these possess high-specific surface area leading to high enzyme loadings. The magnetic nanoparticles (MNPs) are burgeoning in the field of immobilisation as it possess some of the unique properties such as high surface area to volume ratio, uniform particle size, biocompatibility and particularly the recovery of enzymes with the application of an external magnetic field. Immobilisation of industrially important enzymes onto nanoparticles offers overall combined benefits. In this review, the authors here focus on the current scenario in synthesis and functionalisation of MNPs which makes it more compatible for the enzyme immobilisation and its application in the biotechnological industries.

Immobilization of Yarrowia lipolytica Lipase on Macroporous Resin Using Different Methods: Characterization of the Biocatalysts in Hydrolysis Reaction

To improve the reusability and organic solvent tolerance of microbial lipase and expand the application of lipase (hydrolysis, esterification, and transesterification), we immobilized marine microbial lipase using different methods and determined the properties of immobilized lipases. Considering the activity and cost of immobilized lipase, the concentration of lipase was fixed at 2 mg/mL. The optimal temperature of immobilized lipases was 40°C and 5°C higher than free lipase. The activities of immobilized lipases were much higher than free lipase at alkaline pH (more than 50% at pH 12). The free lipase lost most activity (35.3%) and immobilized lipases retained more than 46.4% of their initial activity after 3 h heat treatment at 70°C. At alkaline pH, immobilized lipases were more stable than free lipase (more than 60% residue activity at pH 11 for 3 h). Immobilized lipases retained 80% of their activity after 5 cycles and increased enzyme activity (more than 108.7%) after 3 h treatment in tert-butanol. Immobilization of lipase which improved reusability of lipase and provided a chance to expand the application of marine microbial lipase in organic system expanded the application range of lipase to catalyze hydrolysis and esterification in harsh condition.

Comparative in vitro intestinal digestion of 1,3-diglyceride and 1-monoglyceride rich oils and their mixtures

Intestinal in vitro digestion of 1,3-diolein (DO), 1-monoolein (MO), DO:MO (1:1) rich oils, and triolein (TO), was performed to study the rate and extent of hydrolysis as well as their bioaccessibility in detail, with special emphasis on 1,3-DO and 1-MO forms, as potential bioactive lipids with additional technological functions such as self-emulsifying lipids. The importance of in vitro conditions on non-desirable acylmigration was also shown. The rate of in vitro intestinal lipolysis was in increasing order TO<DO<DO:MO<MO. At the end of digestion, DO:MO was hydrolyzed to absorbable products at the same level than the MO sample. The degree of lipolysis positively correlated with the level of 1-MG and negatively with the level of 2-MG. Either DO, MO or DO:MO produced higher level of 1-MG than TO. DO:MO produced the highest level of 1-MG and a high ratio of 1-MG to 2-MG. Most hydrolysis products (>95%) of DO, MO and DO:MO were found within the micellar phase fraction during digestion, suggesting a high bioaccessibility. A positive correlation between the degree of lipolysis and the number of mixed micelles formed at the end of digestion was found. As summary, the obtained results would enhance the selection of glycerides to formulate ingredients with different purposes. Thus, in case a final high level of 1-MO would be desired to take advantage of the bioactivity of 1-MO, oils under the form of DO or DO:MO might be superior to MO. In case a high 1-MO level together with a low 2-MO level would be desired at the same time, mixtures of DO:MO or MO would be preferred. In case a higher self-emulsifying ability would be desired, the preferred forms would be MO and DO:MO. Finally, in case all the potential functionalities would be desired at the same time, namely the highest bioactivity, together with a high self-emulsifying ability, the mixture DO:MO might be suggested as an interesting product, with the additional economical advantage.