Immobilization of porcine pancreatic lipase on activated carbon by adsorption and covalent bonding and its application in the synthesis of butyl butyrate

Pickering emulsions stabilized by protein/polysaccharide polyelectrolyte complexes for lipase catalysis

The Pickering emulsion stabilized by ovalbumin/pectin polyelectrolyte complex with porcine pancreatic lipase (PPL) dissolved in the aqueous phase was investigated for its feasibility in biphasic catalysis. CLSM and QCM-D analysis revealed that PPL discretely adsorbed to emulsion interface, though they were both negatively charged. The hydrolysis of p-NPP was favored in low stabilizer concentrations and could be saturated by PPL, and the optimum conditions were pH 6.5, ovalbumin to pectin mass ratio 1:3, complex concentration 0.25 %, and PPL dosage 0.6 %. Under these conditions, the Pickering emulsion conferred a conversion rate of 0.87 μmol/h and product yield of 46.8 % after reaction for 5 h, which were significantly lower than 1.37 μmol/h and 73.6 % of the conventional oil/water system. Hence, Pickering emulsions stabilized by protein/polysaccharide polyelectrolyte complexes might not be ideal media for biphasic catalysis, possibly due to the viscoelastic property of the complexes that could better cover emulsion interfaces.

Advances, strategies, and application of immobilized lipase for aroma compound synthesis: Focus on benzyl acetate, isoamyl acetate, and ethyl valerate

Lipases, catalyzing triglyceride hydrolysis, have emerged as versatile biocatalysts for aroma compound synthesis. Aroma compounds, valued for their pleasant scents, have traditional extraction limitations like environmental challenges, low yield and high costs. Lipase-mediated biosynthesis, specially immobilized ones, offers a sustainable and green alternative. Immobilized lipases catalyze transesterification and esterification reactions to produce these compounds with improving enzyme stability, reusability, and overall better catalytic efficiency, making them an appropriate approach for industrial applications. Based on our knowledge, for the first time immobilized lipases for producing benzyl acetate, isoamyl acetate, and ethyl valerate were focused in this review. It also emphasizes how nanotechnology-based supports such as silica, magnetic nanoparticles, and smart polymers improve enzyme stability, reusability, and efficiency. By exploring various immobilization techniques and materials, the review shows how these advances make enzyme use more practical and sustainable for industrial applications. Various immobilized lipases, substrates, and reaction conditions for optimizing these aroma compounds synthesis was discussed.

Enhancing industrial biocatalyst performance and cost-efficiency through adsorption-based enzyme immobilization: A review

Various enzymes such as lipases, proteases and laccases have been extracted for use in various industrial applications. However, most natural enzymes possess characteristics that make them unsuitable for the harsh conditions often associated with industrial processes. To overcome these limitations, various methods and techniques have been developed to enhance the suitability of enzymes as industrial biocatalysts, making them a viable alternative to chemical catalysts. One of the most effective approaches is enzyme immobilization, which improves enzyme properties such as thermal stability, organic solvent stability, enhanced efficiency, catalytic performance, prolonged storage, operational stability, and reusability. These improved characteristics lower manufacturing costs and provide more effective catalysts, making them essential for industrial applications. Enzyme immobilization typically involves attaching the enzyme to a solid support, and the microenvironment including the pH of the binding solution and the nature of the support often influences the immobilization rate. Immobilization techniques also play a crucial role in the success of the process. The adsorption method is being widely used due to its simplicity and minimal impact on enzyme structure. Through hydrogen bonds, ionic interactions, Van der Waals forces, and hydrophobic interactions, this method preserves the enzyme's active site, making it the preferred choice in industrial settings.

Unlocking the potential of microfluidic assisted formulation of exenatide-loaded solid lipid nanoparticles

Exenatide, a first-in-class GLP-1 receptor agonist, is used to control glycaemic levels in type 2 diabetes. There are two approved injectable formulations: one solution for immediate action and one dispersion for prolonged action. Oral exenatide has low bioavailability due to poor gastrointestinal stability and absorption. To address these obstacles, we designed Solid Lipid Nanoparticles (SLN) including DOTAP in the formulation to yield high exenatide encapsulation by hydrophobic ion pairing and DSPE-PEG2kDa to convey colloidal stability and mucus diffusivity. The microfluidic production of SLN yielded 9.7 % exenatide encapsulation and 94.2 % loading efficiency. SLN exhibited solid cored-spherical morphology with sizes of about 120 nm and zeta potential of + 53 mV. The SLN surface charge was modulated by DSPE-PEG2kDa coating; 10 and 30 w/w% DSPE-PEG2kDa /lipid ratios yielded slightly positive and neutral zeta potentials, respectively. All SLN formulations provided exenatide protection from proteolytic enzymes. The non-PEGylated SLN resulted in a twofold increase of exenatide delivery across Caco-2 cell monolayers compared to the peptide solution. The 10 w/w% SLN PEGylation reduced the exenatide delivery compared to non-PEGylated SLN through Caco-2 cell monolayers. However, the exenatide delivery with 10 w/w% PEGylated SLN across mucus-producing Caco-2/HT29-MTX coculture layer was 2-fold higher compared to the unformulated peptide, and 1.5 higher than non-PEGylated SLN. The 30 w/w% SLN PEGylation did not improve the peptide transport neither through Caco-2 cell monolayers nor through Caco-2/HT29-MTX coculture layer.

Immobilized lipase on MIL-53(Al)-AM11 with regulatable hydrophobic surface for flavor ester synthesis

Enzymatic synthesis of flavor esters is crucial for applications in food, beverage, and cosmetics industries. However, the poor activity and stability of free lipase hinder these reaction. Inspired by the concept of lipase interface activation, MIL-53(Al)-NH2 was modified with alkyl acid anhydrides of varying chain lengths to tailor its hydrophobicity, and Candida Rugosa lipase (CRL) was subsequently immobilized on this surface to achieve efficient interface activation. The resulting CRL@MIL-53(Al)-AM11 exhibited 3.5 times higher activity than the unmodified CRL@MIL-53(Al)-NH2. Moreover, CRL@MIL-53(Al)-AM11 enabled one-step purification of crude CRL via selective adsorption. It also showed enhanced storage and thermal stability as well as higher resistance to protease degradation and denaturants than free CRL. CRL@MIL-53(Al)-AM11 retained 75 % of its initial activity after 30 min treatment at 55 °C, whereas the free CRL retained only 41 %. After 11 days of storage, CRL@MIL-53(Al)-AM11 maintained 70 % of its initial activity, in contrast to 36 % for the free lipase. Notably, CRL@MIL-53(Al)-AM11 achieved a 97 % conversion rate in the esterification synthesis of the flavoring substance (butyl butyrate) within 24 h and retained over 40 % conversion after five consecutive cycles. Therefore, this strategy offers a feasible approach for constructing high-performance immobilized lipases for flavor ester synthesis.

Pepsin immobilization on activated carbon and functionalized with glutaraldehyde and genipin for the synthesis of antioxidant peptides of goat casein

In this article, the synthesis of antioxidant peptides in the enzymatic hydrolysis of caprine casein was analyzed at three different time points (60 min, 90 min, and 120 min) using immobilized pepsin on activated and modified carbon (AC, ACF, ACG 50, ACG 100). The immobilization assays revealed a reduction in the biocatalysts' activity compared to the free enzyme. Among the modified ones, ACG 50 exhibited greater activity and better efficiency for reuse cycles, with superior values after 60 min and 90 min. Peptide synthesis was observed under all studied conditions. Analyses (DPPH, β-carotene/linoleic acid, FRAP) confirmed the antioxidant potential of the peptides generated by the immobilized enzyme. However, the immobilized enzyme in ACG 50 and ACG 100, combined with longer hydrolysis times, allowed the formation of peptides with an antioxidant capacity greater than or equivalent to those generated by the free enzyme, despite reduced enzymatic activity.

Alloyed Trimetallic Nanocomposite as an Efficient and Recyclable Solid Matrix for Ideonella sakaiensis Lipase Immobilization

In this work, a trimetallic (Ni/Co/Zn) organic framework (tMOF), synthesized by a solvothermal method, was calcinated at 400 and 600 °C and the final products were used as a support for lipase immobilization. The material annealed at 400 °C (Ni-Co-Zn@400) had an improved surface area (66.01 m2/g) and pore volume (0.194 cm3/g), which showed the highest enzyme loading capacity (301 mg/g) with a specific activity of 0.196 U/mg, and could protect the enzyme against thermal denaturation at 65 °C. The optimal pH and temperature for the lipase were 8.0 and 45 °C but could tolerate pH levels 7.0-8.0 and temperatures 40-60 °C. Moreover, the immobilized enzyme (Ni-Co-Zn@Lipase, Ni-Co-Zn@400@Lipase, or Ni-Co-Zn@600@Lipase) could be recovered and reused for over seven cycles maintaining 80, 90, and 11% of its original activity and maintained a residual activity >90% after 40 storage days. The remarkable thermostability and storage stability of the immobilized lipase suggest that the rigid structure of the support acted as a protective shield against denaturation, while the improved pH tolerance toward the alkaline range indicates a shift in the ionization state attributed to unequal partitioning of hydroxyl and hydrogen ions within the microenvironment of the active site, suggesting that acidic residues may have been involved in forming an enzyme-support bond. The high enzyme loading capacity, specific activity, encouraging stability, and high recoverability of the tMOF@Lipase indicate that a multimetallic MOF could be a better platform for efficient enzyme immobilization.

Surfactant-based metal-organic frameworks (MOFs) in the preparation of an active biocatalysis

Metal-organic frameworks (MOFs) are used as ideal support materials thanks to their unique properties and have become the focus of interest in enzyme immobilization studies, especially in recent years. In order to increase the catalytic activity and stability of Candida rugosa lipase (CRL), a new fluorescence-based MOF (UiO-66-Nap) derived from UiO-66 was synthesized. The structures of the materials were confirmed by spectroscopic techniques such as FTIR, ¹H NMR, SEM, and PXRD. CRL was immobilized on UiO-66-NH₂ and UiO-66-Nap by adsorption technique and immobilization and stability parameters of UiO-66-Nap@CRL were examined. Immobilized lipases UiO-66-Nap@CRL exhibited higher catalytic activity (204 U/g) than UiO-66-NH₂@CRL (168 U/g), which indicates that the immobilized lipase (UiO-66-Nap@CRL) carries sulfonate groups, this is due to strong ionic interactions between the surfactant's polar groups and certain charged locations on the protein surface. The Free CRL lost its catalytic activity completely at 60 °C after 100min, while UiO-66-NH₂@CRL and UiO-66-Nap@CRL retained 45% and 56% of their catalytic activity at the end of 120min, respectively. After 5 cycles, the activity of UiO-66-Nap@CRL remained 50%, while the activity of UiO-66-NH₂@CRL was about 40%. This difference is due to the surfactant groups (Nap) in UiO-66-Nap@CRL. These results show that the newly synthesized fluorescence-based MOF derivative (UiO-66-Nap) can be an ideal support material for enzyme immobilization and can be used successfully to protect and increase the activities of enzymes.

Fucosylated Chondroitin Sulfate against Parkinson's Disease through Inhibiting Inflammation Induced by Gut Dysbiosis

Growing evidence for the importance of the gut-brain axis in Parkinson's disease (PD) has attracted researchers' interest in the possible application of microbiota-based treatment approaches. Using a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model, we looked into the prospect of treating PD with fucosylated chondroitin sulfate obtained from sea cucumbers Isostichopus badionotus (fCS-Ib). We showed that giving fCS-Ib polysaccharide orally greatly reduced the motor deficits, dopamine depletion, and alpha-synuclein increase caused by MPTP in the substantia nigra (SN). It appears that the anti-PD action of fCS-Ib polysaccharide could be attained by squelching inflammation. Glial cell hyperactivation in SN and overproduction of proinflammatory substances in serum could both be suppressed by fCS-Ib polysaccharide injection. The bacterial DNA in fresh colonic feces was submitted to 16S rRNA and untargeted metabolic analyses to confirm the participation of the microbiota-gut-brain axis in the aforementioned interpretation. The findings showed that the MPTP treatment-induced decrease in norank_f_Muribaculaceae and the increase in Staphylococcus were reversed by the administration of fCS-Ib polysaccharide. The NF-κB signaling pathway was shown to be involved in the fCS-Ib polysaccharide-induced anti-inflammation. In conclusion, our research demonstrated for the first time how fCS-Ib polysaccharide combats PD by reducing inflammation caused by gut microbial dysbiosis.