Advances in enzyme biocatalysis for the preparation of functional lipids

Novel reaction systems for catalytic synthesis of structured phospholipids

Phospholipids are distinctive, adaptable molecules that are crucial to numerous biological systems. Additionally, their various architectures and amphiphilic characteristics support their unrivaled crucial functions in scientific and industrial applications. Due to their enormous potential for use in the fields of medicine, food, cosmetics, and health, structured phospholipids, which are modified phospholipids, have garnered increased attention. Traditional extraction methods, however, are pricy, resource-intensive, and low-yielding. The process of enzyme-catalyzed conversion is effective for producing several types of structured phospholipase. However, most frequently employed catalytic procedures involve biphasic systems with organic solvents, which have a relatively large mass transfer resistance and are susceptible to solvent residues and environmental effects due to the hydrophobic nature of phospholipids. Therefore, the adoption of innovative, successful, and environmentally friendly enzyme-catalyzed conversion systems provides a new development route in the field of structured phospholipids processing. Several innovative catalytic reaction systems are discussed in this mini-review, including aqueous-solid system, mixed micelle system, water-in-oil microemulsion system, Pickering emulsion system, novel solvent system, three-liquid-phase system, and supercritical carbon dioxide solvent system. However, there is still a glaring need for a thorough examination of these systems for the enzymatic synthesis of structural phospholipids. In terms of the materials utilized, applicability, benefits and drawbacks, and comparative effectiveness of each system, this research establishes further conditions for the system's selection. To create more effective biocatalytic processes, it is still important to build green biocatalytic processes with improved performance. KEY POINTS: • The latest catalytic systems of phospholipase D are thoroughly summarized. • The various systems are contrasted, and their traits are enumerated. • Different catalytic systems' areas of applicability and limitations are discussed.

Immobilized lipase enzyme on green synthesized magnetic nanoparticles using Psidium guava leaves for dye degradation and antimicrobial activities

Zinc ferrite nanoparticles (ZnF NPs) were synthesized by a green method using Psidium guava Leaves extract and characterized via structural and optical properties. The surface of ZnF NPs was stabilized with citric acid (CA) by a direct addition method to obtain (ZnF-CA NPs), and then lipase (LP) enzyme was immobilized on ZnF-CA NPs to obtain a modified ZnF-CA-LP nanocomposite (NCs). The prepared sample's photocatalytic activity against Methylene blue dye (MB) was determined. The antioxidant activity of ZnF-CA-LP NCs was measured using 1,1-diphenyl-2-picryl hydrazyl (DPPH) as a source of free radicals. In addition, the antibacterial and antibiofilm capabilities of these substances were investigated by testing them against gram-positive Staphylococcus aureus (S. aureus ATCC 25923) and gram-negative Escherichia coli (E. coli ATCC 25922) bacterial strains. The synthesized ZnF NPs were discovered to be situated at the core of the material, as determined by XRD, HRTEM, and SEM investigations, while the CA and lipase enzymes were coated in this core. The ZnF-CA-LP NCs crystallite size was around 35.0 nm at the (311) plane. Results obtained suggested that 0.01 g of ZnF-CA-LP NCs achieved 96.0% removal of 5.0 ppm of MB at pH 9.0. In-vitro zone of inhibition (ZOI) and minimum inhibitory concentration (MIC) results verified that ZnF-CA-LP NCs exhibited its encouraged antimicrobial activity against S. aureus and E. coli (20.0 ± 0.512, and 27.0 ± 0.651 mm ZOI, respectively) & (1.25, and 0.625 μg/ml MIC, respectively). ZnF-CA-LP NPs showed antibiofilm percentage against S. aureus (88.4%) and E. coli (96.6%). Hence, ZnF-CA-LP NCs are promising for potential applications in environmental and biomedical uses.

The discovery of regional neurotoxicity-associated metabolic alterations induced by carbon quantum dots in brain of mice using a spatial metabolomics analysis

BACKGROUND

Recently, carbon quantum dots (CQDs) have been widely used in various fields, especially in the diagnosis and therapy of neurological disorders, due to their excellent prospects. However, the associated inevitable exposure of CQDs to the environment and the public could have serious severe consequences limiting their safe application and sustainable development.

RESULTS

In this study, we found that intranasal treatment of 5 mg/kg BW (20 µL/nose of 0.5 mg/mL) CQDs affected the distribution of multiple metabolites and associated pathways in the brain of mice through the airflow-assisted desorption electrospray ionization mass spectrometry imaging (AFADESI-MSI) technique, which proved effective in discovery has proven to be significantly alerted and research into tissue-specific toxic biomarkers and molecular toxicity analysis. The neurotoxic biomarkers of CQDs identified by MSI analysis mainly contained aminos, lipids and lipid-like molecules which are involved in arginine and proline metabolism, biosynthesis of unsaturated fatty acids, and glutamine and glutamate metabolism, etc. as well as related metabolic enzymes. The levels or expressions of these metabolites and enzymes changed by CQDs in different brain regions would induce neuroinflammation, organelle damage, oxidative stress and multiple programmed cell deaths (PCDs), leading to neurodegeneration, such as Parkinson's disease-like symptoms. This study enlightened risk assessments and interventions of QD-type or carbon-based nanoparticles on the nervous system based on toxic biomarkers regarding region-specific profiling of altered metabolic signatures.

CONCLUSION

These findings provide information to advance knowledge of neurotoxic effects of CQDs and guide their further safety evaluation.

Enzymatic Synthesis of Structured Lipids Enriched with Medium- and Long-Chain Triacylglycerols via Pickering Emulsion-Assisted Interfacial Catalysis: A Preliminary Exploration

Medium- and long-chain triacylglycerol (MLCT), as a novel functional lipid, is valuable due to its special nutritional properties. Its low content in natural resources and inefficient synthesis during preparation have limited its practical applications. In this study, we developed an effective Pickering emulsion interfacial catalysis system (PE system) for the enzymatic synthesis of MLCT by trans-esterification. Lipase NS 40086 served simultaneously as a catalyst and a solid emulsifier to stabilize the Pickering emulsion. Benefitting from the sufficient oil-water interface, the obtained PE system exhibited outstanding catalytic efficiency, achieving 77.5% of MLCT content within 30 min, 26% higher than that of a water-free system. The Km value (0.259 mM) and activation energy (14.45 kJ mol-1) were 6.8-fold and 1.6-fold lower than those of the water-free system, respectively. The kinetic parameters as well as the molecular dynamics simulation and the tunnel analysis implied that the oil-water interface enhanced the binding between substrate and lipase and thus boosted catalytic efficiency. The conformational changes in the lipase were further explored by FT-IR. This method could give a novel strategy for enhancing lipase activity and the design of efficient catalytic systems to produce added-value lipids. This work will open a new methodology for the enzymatic synthesis of structured lipids.

Highly effective synthesis of novel structured phospholipid emulsifiers using magnetically recyclable Fe3O4@SiO2/M (M = Zn or Al) composite

It is of great importance to develop a most efficient, recyclable, and ecofriendly process to produce novel structured phospholipid emulsifiers. Herein, innovative medium-chain structured phospholipid (MCSPL) emulsifiers were synthesized through transesterification of soybean lecithins with medium-chain fatty acids (MCFAs) promoted by Zn- or Al-incorporated Fe3O4@SiO2, denoted by Fe3O4@SiO2/M (M = Zn or Al). Resultingly, Fe3O4@SiO2/M (M = Zn or Al) exhibited the most superior reactivity with 97.1% or 88.7% MCFA incorporation to other benchmark catalysts and also had excellent magnetic separability and recyclability. Noticeably, targeted MCSPLs possessed almost more superior emulsifying properties to other phospholipid emulsifiers, and had potential for use as oil-in-water emulsifiers. Conclusively, the present findings demonstrate that transesterification promoted by Fe3O4@SiO2/M (M = Zn or Al) can be a promising approach for green, economic, and highly effective synthesis of novel dual-function phospholipid emulsifiers with bioactive and emulsifying properties in food, pharmaceutical, and cosmetic industries.

Enzyme engineering for functional lipids synthesis: recent advance and perspective

Functional lipids, primarily derived through the modification of natural lipids by various processes, are widely acknowledged for their potential to impart health benefits. In contrast to chemical methods for lipid modification, enzymatic catalysis offers distinct advantages, including high selectivity, mild operating conditions, and reduced byproduct formation. Nevertheless, enzymes face challenges in industrial applications, such as low activity, stability, and undesired selectivity. To address these challenges, protein engineering techniques have been implemented to enhance enzyme performance in functional lipid synthesis. This article aims to review recent advances in protein engineering, encompassing approaches from directed evolution to rational design, with the goal of improving the properties of lipid-modifying enzymes. Furthermore, the article explores the future prospects and challenges associated with enzyme-catalyzed functional lipid synthesis.

Transforming the fermented fish landscape: Microbiota enable novel, safe, flavorful, and healthy products for modern consumers

Regular consumption of fish promotes sustainable health while reducing negative environmental impacts. Fermentation has long been used for preserving perishable foods, including fish. Fermented fish products are popular consumer foods of historical and cultural significance owing to their abundant essential nutrients and distinct flavor. This review discusses the recent scientific progress on fermented fish, especially the involved flavor formation processes, microbial metabolic activities, and interconnected biochemical pathways (e.g., enzymatic/non-enzymatic reactions associated with lipids, proteins, and their interactions). The multiple roles of fermentation in preservation of fish, development of desirable flavors, and production of health-promoting nutrients and bioactive substances are also discussed. Finally, prospects for further studies on fermented fish are proposed, including the need of monitoring microorganisms, along with the precise control of a fermentation process to transform the traditional fermented fish to novel, flavorful, healthy, and affordable products for modern consumers. Microbial-enabled innovative fermented fish products that consider both flavor and health benefits are expected to become a significant segment in global food markets. The integration of multi-omics technologies, biotechnology-based approaches (including synthetic biology and metabolic engineering) and sensory and consumer sciences, is crucial for technological innovations related to fermented fish. The findings of this review will provide guidance on future development of new or improved fermented fish products through regulating microbial metabolic processes and enzymatic activities.