Immobilization of Candida rugosa lipase on bentonite modified with benzyltriethylammonium chloride

Characterization of free and immobilized lipase from Penicillium sp. onto three modified bentonites: A comparative study

The present work was conducted to investigate the immobilization of lipase from Penicillium sp. onto three modified bentonites by simple adsorption and crosslinking methods. The composites were characterized by FTIR, SEM and BET. The free and bentonite-supported lipase was evaluated in terms of operational and storage stability and pH and thermal activity and stability. The kinetic parameters were also evaluated. The results show that all immobilized enzymes had better thermal and pH stability compared to free enzymes. Among the immobilized enzymes, GDU-bent-lipase had more efficient performance in thermal (38% of its initial activity within 24 h at 65 °C), operational (70% residual activity after 9 cycles), storage stability (70.14% of its initial activities at 4 °C for 21 days), and kinetic properties (effectiveness factor 0.79 relative to free enzyme) than free and other immobilized enzymes. The adsorption isotherm was modeled by Langmuir, Freundlich and Temkin isotherms which Langmuir isotherm indicated a better fit of the experimental adsorption data. To the best of our knowledge, this is the first comparative report about the immobilization of lipase Produced by Penicillium sp., isolated from olive mill wastewater, and the most comprehensive study about the immobilization of lipase onto several supports.

Nanobiocatalyst consisting of immobilized α-amylase on montmorillonite exhibiting enhanced enzymatic performance based on the allosteric effect

Enzyme immobilization on nanostructured substrates is an emerging method for the efficient development of nanobiocatalysts to enhance enzymatic performance. In this study, a novel α-amylase nanobiocatalytic system was constructed based on the allosteric activation of the enzyme and its immobilization on a natural nanostructured mineral montmorillonite. The strategy of allosteric modulation and immobilization, equipped the immobilized α-amylase with higher catalytic activity and greater stability (compared to those of free α-amylase) over a broad range of pH values (4.5-9.0) and temperatures (30-80 °C). Kinetic experiments revealed that although the immobilized α-amylase possessed a considerably lower affinity for its substrate, its catalytic activity was higher than that of free α-amylase, likely owing to allosteric modulation. Thus, this study demonstrates a convenient and environmentally benign immobilization strategy to construct a nanobiocatalytic α-amylase system that exploits the phenomenon of allosteric activation of the enzyme and lays the foundation for further industrial applications.

Comparative Study on Lipase Immobilized onto Organo-Cation Exchanged Kaolin and Metakaolin: Surface Properties and Catalytic Activity

Clay mineral has received much attention to be used as biocatalysts as it is cheaper, easily available and environmentally friendly. However, the use of unmodified clay, in particular kaolin for enzyme immobilization showed unsuitability of this support due to its negative charge. In this study, the hydrophobic properties of kaolin and metakaolin (kaolin heated to 650 °C) were adjusted by the intercalation with benzyltriethylammonium chloride (BTEA-Cl), at concentrations 2.0 times the cation exchange capacities (CEC) of the clays. The supports were then used for immobilization of lipase from Candida rugosa (CRL). From the study, the highest percentage of lipase immobilization was achieved (70.14%), when organo-modified metakaolin (2.0 MK) was used. The supports as well as the immobilized biocatalysts were then characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and nitrogen adsorption techniques. Comparisons of the efficiencies of immobilized with free CRL in the synthesis of nonyl hexanoate showed that immobilized CRL achieved enzymatic activities of between 5.24×10−3 to 3.63×10−3 mmol/min/mg, while free CRL achieved enzymatic activity of 3.27×10−3 mmol/min/mg after 5 h of reaction at 30 ℃. The immobilized CRLs also maintained 70.81% – 80.59% thermostabilities at 70 ℃ as compared to the free CRL (28.13%). CRL immobilized on 2.0 NK and 2.0 MK also maintained 38.54% and 62.56%, respectively, of the initial activities after 10 continuous cycles, showing the excellent stability and reusability of the immobilized lipases, suitable as substitute for expensive, hazardous catalysts used in industries. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

Covalent immobilization of lipase from Candida rugosa on epoxy-activated cloisite 30B as a new heterofunctional carrier and its application in the synthesis of banana flavor and production of biodiesel

In this paper, an epoxy-activated cloisite (ECL) was prepared as a new heterofunctional carrier via a reaction between cloisite 30B (CL) and epichlorohydrin and utilized for covalent immobilization of lipase from Candida rugosa. The lipase immobilized on the ECL (LECL) was successfully used in the olive oil hydrolysis, synthesis of isoamyl acetate (banana flavor), and biodiesel production. The TGA, FT-IR, SEM, and XRD were used to characterize CL, ECL, and LECL. The influences of temperature, pH, thermal stability, and storage capacity were examined in the olive oil hydrolysis. The effects of solvent, temperature, time, water content, and substrates molar ratio on the yields of ester and biodiesel were also investigated. In the optimized conditions, the hydrolytic activity of LECL was 1.85 ± 0.05 U/ mg, and the maximum yield of ester and biodiesel was 91.6% and 95.4%, respectively. The LECL showed good thermal stability and storage capacity compared to the free lipase. Additionally, LECL was reusable for both esterification and transesterification after being used for nine cycles.

Immobilization of Amano lipase AK from Pseudomonas fluorescens on different types of chitosan-containing supports: use in the kinetic resolution of rac-indanol

Amano lipase AK from P. fluorescens was immobilized on different types of chitosan-containing supports. Chitosan lower molecular weight (2.5%), chitosan lower molecular weight/sodium alginate (2.5%/2.5%) and chitosan lower molecular weight/carrageenan (2.5%/2.5%) allowed the highest values of immobilization yields (IY) of 81, 81 and 83%, respectively. Best activity results were achieved using chitosan average molecular weight (5%) and chitosan lower molecular weight/sodium alginate (2.5%/2.5%) as support, with values of 1.40 and 1.30 U_pNPB/g_gel and with recovery activities of 45.75 and 35.6%, respectively. These derivatives were evaluated in the kinetic resolution of rac-indanol to obtain a key intermediate in the synthesis of a drug used in the treatment of Parkinson's disease. The most efficient derivatives in the kinetic resolution were lipase immobilized on chitosan average molecular weight (5.0%) and chitosan low molecular weight/sodium alginate, the latter leading to obtaining both (S)-indanol and (R)-indanyl acetate with > 99% ee and 50% conversion.

Immobilization of Candida cylindracea Lipase by Covalent Attachment on Glu-Modified Bentonite

Alkaline Ca-bentonite, obtained upon acid activation and base load of natural bentonite, has a good anion exchange capability. Glu-modified alkaline Ca-bentonites were further prepared by covalent binding with glutamic acid for the immobilization of lipase OF from Candida cylindracea. The obtained immobilized lipase demonstrated a significantly higher catalytic activity than that of unmodified alkaline Ca-bentonite, giving a specific activity of 62.1 U mg^-1 protein, twice that of the unmodified carrier, and a total activity of 391.2 U g^-1 support, retaining ~ 82.3% of the activity after being reused five times for olive oil emulsion hydrolysis. X-ray diffraction and Fourier transform infrared spectroscopy assays demonstrated the successful immobilization of the lipase on the surface of the bentonite. Upon immobilization, the thermostability of the lipase improved remarkably. At 50 °C, free lipase retained only 6.0% of its initial activity at 6 h, in comparison with 15% for Ca-Bent-lipase and 50% for Glu-Ca-Bent-lipase after 8 h. The Glu-Ca-Bent-lipase is proved as an effective biocatalyst for the biodiesel preparation, improving the transesterification reaction conversion from 52.8% in the condition of free lipase to 99.9% and keeping at 56.2% after being reused five times, while the free lipase was inactive upon two reuses. The above results provide a new route in the use of inexpensive bentonite for the enzyme immobilization.

Heterogeneous Fenton-like catalysis of Fe-MOF derived magnetic carbon nanocomposites for degradation of 4-nitrophenol

Magnetic Fe–C_x as heterogeneous Fenton-like catalysts were synthesized by the pyrolysis of Fe-MOF, and the catalytic activity of Fe–C_x for removal of 4-NP was significantly affected by pyrolysis temperature.

Nanoclays for Lipase Immobilization: Biocatalyst Characterization and Activity in Polyester Synthesis

The immobilization of Candida antarctica lipase B (CALB) was performed by physical adsorption on both neat and organo-modified forms of sepiolite and montmorillonite. The influence of different parameters, e.g., solvent, enzyme loading, cross-linking, and type of clay support, on immobilization efficiency and catalyst hydrolytic activity has been investigated. The highest hydrolytic activities were obtained for CALB immobilized on organo-modified clay minerals, highlighting the beneficial effect of organo-modification. The esterification activity of these CALB/organoclay catalysts was also tested in the ring-opening polymerization of ε-caprolactone. The polymerization kinetics observed for clay-immobilized catalysts confirmed that CALB adsorbed on organo-modified montmorillonite (CALB/MMTMOD) was the highest-performing catalytic system.