Catalysts

Editorial

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3 pages, 185 KiB

Open AccessEditorial

Special Issue “Biocatalysts: Design and Application”

by Cesar Mateo and Jose M. Palomo

Catalysts 2021, 11(7), 778; https://doi.org/10.3390/catal11070778 - 27 Jun 2021

Viewed by 1388

Abstract

The use of biocatalysts in chemical reactions is of great interest because reactions can be carried out under very mild and green conditions [...] Full article

(This article belongs to the Special Issue Biocatalysts: Design and Application)

Research

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16 pages, 4493 KiB

Open AccessArticle

Immobilization of a Novel EST_BAS Esterase from Bacillus altitudinis onto an Epoxy Resin: Characterization and Regioselective Synthesis of Chloramphenicol Palmitate

by Fengying Dong, Xudong Tang, Xiaohui Yang, Lin Lin, Dannong He, Wei Wei and Dongzhi Wei

Catalysts 2019, 9(7), 620; https://doi.org/10.3390/catal9070620 - 21 Jul 2019

Cited by 6 | Viewed by 3857

Abstract

Novel gene est_BAS from Bacillus altitudinis, encoding a 216-amino acid esterase (Est_BAS) with a signal peptide (SP), was expressed in Escherichia coli. Est_BASΔSP showed the highest activity toward p-nitrophenyl hexanoate at 50 °C and pH [...] Read more.

Novel gene est_BAS from Bacillus altitudinis, encoding a 216-amino acid esterase (Est_BAS) with a signal peptide (SP), was expressed in Escherichia coli. Est_BASΔSP showed the highest activity toward p-nitrophenyl hexanoate at 50 °C and pH 8.0 and had a half-life (T_1/2) of 6 h at 50 °C. Est_BASΔSP was immobilized onto a novel epoxy resin (Lx-105s) with a high loading of 96 mg/g. Fourier transform infrared (FTIR) spectroscopy showed that Est_BASΔSP was successfully immobilized onto Lx-105s. In addition, immobilization improved its enzymatic performance by widening the tolerable ranges of pH and temperature. The optimum temperature of immobilized Est_BASΔSP (Lx-Est_BASΔSP) was higher, 60 °C, and overall thermostability improved. T_1/2 of Lx-Est_BASΔSP and free Est_BASΔSP at 60 °C was 105 and 28 min, respectively. Lx-Est_BASΔSP was used as a biocatalyst to synthesize chloramphenicol palmitate by regioselective modification at the primary hydroxyl group. Conversion efficiency reached 94.7% at 0.15 M substrate concentration after 24 h. Lx-Est_BASΔSP was stable and could be reused for seven cycles, after which it retained over 80% of the original activity. Full article

(This article belongs to the Special Issue Biocatalysts: Design and Application)

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16 pages, 1427 KiB

Open AccessArticle

Novel Combi-lipase Systems for Fatty Acid Ethyl Esters Production

by Esteban C. Toro, Diego F. Rodríguez, Nelson Morales, Lina M. García and César A. Godoy

Catalysts 2019, 9(6), 546; https://doi.org/10.3390/catal9060546 - 18 Jun 2019

Cited by 29 | Viewed by 4272

Abstract

Most Combi-lipases (CL) are based on mixtures of different lipases immobilized on different supports. The increased CL efficiency has been attributed solely to the complementary selectivity of lipases. However, the role of the immobilization support in CL or in co-immobilized systems (co [...] Read more.

Most Combi-lipases (CL) are based on mixtures of different lipases immobilized on different supports. The increased CL efficiency has been attributed solely to the complementary selectivity of lipases. However, the role of the immobilization support in CL or in co-immobilized systems (coCL) and the application of kinetic models to account CL composition effects, have not been assessed. In this work, commercial lipases from Thermomyces lunuginosus (TLL), Candida antarctica (CALB) and Rhizomocur miehei (RML) and supports as Lewatit^®VPOC1600 (LW) and Purolite^®ECR1604 (PU), were combined to produce new CL systems for the production of fatty acid ethyl esters (EE) which are the main component of ethylic biodiesel: Co-immobilization slightly altered palm olein EE yields with regard to that of equivalent CL systems, e.g., the best coCL of TLL and CALB in LW (89.5%) and the respective CL (81.8%). The support did affect CL behavior: (i) The best coCL of TLL and RML on LW produced 80.0% EE while on PU 76.4%; (ii) CL based on mixtures of the same enzyme, but immobilized on different supports (semiCL) show complementarity: The best TLL semiCL produced 86.1% EE while its constituents (LW) and (PU) produced individually 78.2 and 70.3%, respectively. The proposed model accounts adequately the EE production properties for CL systems based on TLL, CALB and LW. This work expands the tools to obtain new CL systems for EE production. Full article

(This article belongs to the Special Issue Biocatalysts: Design and Application)

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13 pages, 1211 KiB

Open AccessArticle

Efficient Biocatalytic Preparation of Optically Pure (R)-1-[4-(Trifluoromethyl)phenyl]ethanol by Recombinant Whole-Cell-Mediated Reduction

by Ying Chen, Nana Xia, Yuewang Liu and Pu Wang

Catalysts 2019, 9(4), 391; https://doi.org/10.3390/catal9040391 - 25 Apr 2019

Cited by 6 | Viewed by 3539

Abstract

(R)-1-[4-(Trifluoromethyl)phenyl]ethanol is an important pharmaceutical intermediate of a chemokine CCR5 antagonist. In the present study, a bioprocess for the asymmetric reduction of 4-(trifluoromethyl)acetophenone to (R)-1-[4-(trifluoromethyl)phenyl]ethanol was developed by recombinant Escherichia coli cells with excellent enantioselectivity. In order to overcome [...] Read more.

(R)-1-[4-(Trifluoromethyl)phenyl]ethanol is an important pharmaceutical intermediate of a chemokine CCR5 antagonist. In the present study, a bioprocess for the asymmetric reduction of 4-(trifluoromethyl)acetophenone to (R)-1-[4-(trifluoromethyl)phenyl]ethanol was developed by recombinant Escherichia coli cells with excellent enantioselectivity. In order to overcome the conversion limitation performed in the conventional buffer medium resulting from poor solubility of non-natural substrate, we subsequently established a polar organic solvent-aqueous medium to improve the efficacy. Isopropanol was selected as the most suitable cosolvent candidate, based on the investigation on a substrate solubility test and cell membrane permeability assay in different organic solvent-buffer media. Under the optimum conditions, the preparative-scale asymmetric reduction generated a 99.1% yield with >99.9% product enantiomeric excess (ee) in a 15% (v/v) isopropanol proportion, at 100 mM of 4-(trifluoromethyl)acetophenone within 3 h. Compared to bioconversion in the buffer medium, the developed isopropanol-aqueous system enhanced the substrate concentration by 2-fold with a remarkably improved yield (from 62.5% to 99.1%), and shortened the reaction time by 21 h. Our study gave the first example for a highly enantioselective production of (R)-1-[4-(trifluoromethyl)phenyl]ethanol by a biological method, and the bioreduction of 4-(trifluoromethyl)acetophenone in a polar organic solvent-aqueous system was more efficient than that in the buffer solution only. This process is also scalable and has potential in application. Full article

(This article belongs to the Special Issue Biocatalysts: Design and Application)

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14 pages, 21952 KiB

Open AccessArticle

Tailoring a Soluble Diiron Monooxygenase for Synthesis of Aromatic N-oxides

by Vytautas Petkevičius, Justas Vaitekūnas, Dovydas Vaitkus, Narimantas Čėnas and Rolandas Meškys

Catalysts 2019, 9(4), 356; https://doi.org/10.3390/catal9040356 - 12 Apr 2019

Cited by 7 | Viewed by 4144

Abstract

The aromatic N-oxides have received increased attention over the last few years due to their potential application in medicine, agriculture and organic chemistry. As a green alternative in their synthesis, the biocatalytic method employing whole cells of Escherichia coli bearing phenol monooxygenase [...] Read more.

The aromatic N-oxides have received increased attention over the last few years due to their potential application in medicine, agriculture and organic chemistry. As a green alternative in their synthesis, the biocatalytic method employing whole cells of Escherichia coli bearing phenol monooxygenase like protein PmlABCDEF (from here on – PML monooxygenase) has been introduced. In this work, site-directed mutagenesis was used to study the contributions of active site neighboring residues I106, A113, G109, F181, F200, F209 to the regiospecificity of N-oxidation. Based on chromogenic indole oxidation screening, a collection of PML mutants with altered catalytic properties was created. Among the tested mutants, the A113G variant acquired the most distinguishable N-oxidations capacity. This new variant of PML was able to produce dioxides (quinoxaline-1,4-dioxide, 2,5-dimethylpyrazine-1,4-dioxide) and specific mono-N-oxides (2,3,5-trimethylpyrazine-1-oxide) that were unachievable using the wild type PML. This mutant also featured reshaped regioselectivity as N-oxidation shifted towards quinazoline-1-oxide compared to quinazoline-3-oxide that is produced by the wild type PML. Full article

(This article belongs to the Special Issue Biocatalysts: Design and Application)

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13 pages, 2154 KiB

Open AccessArticle

Production of 1,3-Propanediol from Pure and Crude Glycerol Using Immobilized Clostridium butyricum

by Igor Dolejš, Monika Líšková, Vladimír Krasňan, Kristína Markošová, Michal Rosenberg, Fabio Lorenzini, Andrew C. Marr and Martin Rebroš

Catalysts 2019, 9(4), 317; https://doi.org/10.3390/catal9040317 - 31 Mar 2019

Cited by 23 | Viewed by 6127

Abstract

The present study describes the production of the value-added chemical 1,3-propanediol (1,3-PD) from crude glycerol, a waste by-product formed during biodiesel production. The efficiency, robustness, and stability of the process were improved by immobilization of the anaerobic bacterium Clostridium butyricum into a polyvinyl [...] Read more.

The present study describes the production of the value-added chemical 1,3-propanediol (1,3-PD) from crude glycerol, a waste by-product formed during biodiesel production. The efficiency, robustness, and stability of the process were improved by immobilization of the anaerobic bacterium Clostridium butyricum into a polyvinyl alcohol (PVA) hydrogel. The highest average productivity, 6.8 ± 0.2 g/(L·h), was achieved in 10 consecutive, repeated batch fermentations, with an initial concentration of pure glycerol 45.5 ± 0.7 g/L, after 2.5 h. The highest final concentration and yield of 1,3-PD, 28.3 ± 0.6 g/L, and 0.42 ± 0.01 g/g, respectively, were achieved in eleven repeated batch fermentations, after increasing the initial pure glycerol concentration to 70.4 ± 1.9 g/L. Two different types of crude glycerol, produced from used cooking oil (UCO) and rapeseed oil (RO), were tested in repeated batch fermentations, with an average productivity achieved of 2.3 ± 0.1 and 3.5 ± 0.3 g/(L·h), respectively. The highest final concentration and yield of 1,3-PD, 12.6 ± 0.9 g/L, and 0.35 ± 0.02 g/g, respectively, were observed in fifteen repeated batch fermentations with RO crude glycerol. An excellent stability of the immobilized anaerobic bacteria and increase of productivity in fermentation of crude glycerol was demonstrated. Full article

(This article belongs to the Special Issue Biocatalysts: Design and Application)

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12 pages, 3370 KiB

Open AccessArticle

Alkaline Modification of a Metal–Enzyme–Surfactant Nanocomposite to Enhance the Production of L-α-glycerylphosphorylcholine

by Hui Li, Xun Cao, Yuanyuan Lu, Yan Ni, Xin Wang, Qiuhao Lu, Ganlu Li, Kequan Chen, Pingkai Ouyang and Weimin Tan

Catalysts 2019, 9(3), 237; https://doi.org/10.3390/catal9030237 - 4 Mar 2019

Cited by 5 | Viewed by 3123

Abstract

Microenvironment modification within nanoconfinement can maximize the catalytic activity of enzymes. Phospholipase A₁ (PLA₁) has been used as the biocatalyst to produce high value L-α-glycerylphosphorylcholine (L-α-GPC) through hydrolysis of phosphatidylcholine (PC). We successfully developed a simple co-precipitation method to encapsulate [...] Read more.

Microenvironment modification within nanoconfinement can maximize the catalytic activity of enzymes. Phospholipase A₁ (PLA₁) has been used as the biocatalyst to produce high value L-α-glycerylphosphorylcholine (L-α-GPC) through hydrolysis of phosphatidylcholine (PC). We successfully developed a simple co-precipitation method to encapsulate PLA₁ in a metal–surfactant nanocomposite (MSNC), then modified it using alkalescent 2-Methylimidazole (2-Melm) to promote catalytic efficiency in biphasic systems. The generated 2-Melm@PLA₁/MSNC showed higher catalytic activity than PLA₁/MSNC and free PLA₁. Scanning electron microscopy and transmission electron microscopy showed a typical spherical structure of 2-Melm@PLA₁/MSNC at about 50 nm, which was smaller than that of 2-Melm@MSNC. Energy disperse spectroscopy, N₂ adsorption isotherms, Fourier transform infrared spectrum, and high-resolution X-ray photoelectron spectroscopy proved that 2-Melm successfully modified PLA₁/MSNC. The generated 2-Melm@PLA₁/MSNC showed a high catalytic rate per unit enzyme mass of 1.58 μmol mg^-1 min^-1 for the formation of L-α-GPC. The 2-Melm@PLA₁/MSNC also showed high thermal stability, pH stability, and reusability in a water–hexane biphasic system. The integration of alkaline and amphiphilic properties of a nanocomposite encapsulating PLA₁ resulted in highly efficient sequenced reactions of acyl migration and enzymatic hydrolysis at the interface of a biphasic system, which cannot be achieved by free enzyme. Full article

(This article belongs to the Special Issue Biocatalysts: Design and Application)

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16 pages, 1694 KiB

Open AccessArticle

Cross-Linking with Polyethylenimine Confers Better Functional Characteristics to an Immobilized β-glucosidase from Exiguobacterium antarcticum B7

by Ricardo Rodrigues de Melo, Robson Carlos Alnoch, Amanda Silva de Sousa, Hélia Harumi Sato, Roberto Ruller and Cesar Mateo

Catalysts 2019, 9(3), 223; https://doi.org/10.3390/catal9030223 - 1 Mar 2019

Cited by 8 | Viewed by 3197

Abstract

β-glucosidases are ubiquitous, well-characterized and biologically important enzymes with considerable uses in industrial sectors. Here, a tetrameric β-glucosidase from Exiguobacterium antarcticum B7 (EaBglA) was immobilized on different activated agarose supports followed by post-immobilization with poly-functional macromolecules. The best result was obtained [...] Read more.

β-glucosidases are ubiquitous, well-characterized and biologically important enzymes with considerable uses in industrial sectors. Here, a tetrameric β-glucosidase from Exiguobacterium antarcticum B7 (EaBglA) was immobilized on different activated agarose supports followed by post-immobilization with poly-functional macromolecules. The best result was obtained by the immobilization of EaBglA on metal glutaraldehyde-activated agarose support following cross-linking with polyethylenimine. Interestingly, the immobilized EaBglA was 46-fold more stable than its free form and showed optimum pH in the acidic region, with high catalytic activity in the pH range from 3 to 9, while the free EaBglA showed catalytic activity in a narrow pH range (>80% at pH 6.0–8.0) and optimum pH at 7.0. EaBglA had the optimum temperature changed from 30 °C to 50 °C with the immobilization step. The immobilized EaBglA showed an expressive adaptation to pH and it was tolerant to ethanol and glucose, indicating suitable properties involving the saccharification process. Even after 9 cycles of reuse, the immobilized β-glucosidase retained about 100% of its initial activity, demonstrating great operational stability. Hence, the current study describes an efficient strategy to increase the functional characteristics of a tetrameric β-glucosidase for future use in the bioethanol production. Full article

(This article belongs to the Special Issue Biocatalysts: Design and Application)

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12 pages, 2452 KiB

Open AccessArticle

Isolation of a Bacillus Aryabhattai Strain for the Resolution of (R, S)-Ethyl Indoline-2-Carboxylate to Produce (S)-Indoline-2-Carboxylic Acid

by Yinjun Zhang, Jialin Chen, Changsheng Chen and Shijin Wu

Catalysts 2019, 9(2), 206; https://doi.org/10.3390/catal9020206 - 25 Feb 2019

Cited by 5 | Viewed by 3275

Abstract

The strain screened from sludge can selectively hydrolyze (S)-ethyl indoline-2-carboxylate to produce (S)-indoline-2-carboxylic acid. It was identified as the Bacillus aryabhattai strain based on its morphology, metabolism, and 16S rDNA sequence analysis. Glucose and yeast powder were used as [...] Read more.

The strain screened from sludge can selectively hydrolyze (S)-ethyl indoline-2-carboxylate to produce (S)-indoline-2-carboxylic acid. It was identified as the Bacillus aryabhattai strain based on its morphology, metabolism, and 16S rDNA sequence analysis. Glucose and yeast powder were used as the best carbon and nitrogen sources to cultured cells with an initial pH of seven. Subsequently, we optimized the key parameters for selective hydrolysis. Finally, when the substrate concentration had reached 3%, with a 35 °C water bath, a pH of seven, and a speed of 600 rpm, the e.e._p value attained 96% with a 33% yield. Thus, we had developed a new method for producing (S)-indoline-2-carboxylic acid that used whole microbial cells as the biocatalyst. Full article

(This article belongs to the Special Issue Biocatalysts: Design and Application)

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9 pages, 1600 KiB

Open AccessArticle

Design and Characterization of a Novel Artificial Peroxidase

by Ye Yuan, Jia Xu, Zhenyu Zhao, Hui Li, Kai Wang, Zhi Wang and Liping Wang

Catalysts 2019, 9(2), 168; https://doi.org/10.3390/catal9020168 - 11 Feb 2019

Cited by 5 | Viewed by 5496

Abstract

In this study, we reported on a novel mimetic peroxidase, deuterohemin–Ala–His–Glu, (Dh–A–H–E). The kinetic parameters of Dh–A–H–E suggested that it was a mimetic peroxidase and followed the ping–pong mechanism. Compared to horseradish peroxidase, Dh–A–H–E exhibited excellent stability when tested at different pH and [...] Read more.

In this study, we reported on a novel mimetic peroxidase, deuterohemin–Ala–His–Glu, (Dh–A–H–E). The kinetic parameters of Dh–A–H–E suggested that it was a mimetic peroxidase and followed the ping–pong mechanism. Compared to horseradish peroxidase, Dh–A–H–E exhibited excellent stability when tested at different pH and temperatures, and using different organic solvents. Based on our above results, a new method using Dh–A–H–E has successfully been developed for the fast and quantitative detection of trace amounts of glucose. Full article

(This article belongs to the Special Issue Biocatalysts: Design and Application)

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12 pages, 2687 KiB

Open AccessArticle

Enzyme-Loaded Mesoporous Silica Particles with Tuning Wettability as a Pickering Catalyst for Enhancing Biocatalysis

by Tao Meng, Ruixue Bai, Weihao Wang, Xin Yang, Ting Guo and Yaolei Wang

Catalysts 2019, 9(1), 78; https://doi.org/10.3390/catal9010078 - 14 Jan 2019

Cited by 16 | Viewed by 5336

Abstract

Pickering emulsion systems have created new opportunities for two-phase biocatalysis, however their catalytic performance is often hindered by biphasic mass transfer process relying on the interfacial area. In this study, lipase-immobilized mesoporous silica particles (LMSPs) are employed as both Pickering stabilizers and biocatalysts. [...] Read more.

Pickering emulsion systems have created new opportunities for two-phase biocatalysis, however their catalytic performance is often hindered by biphasic mass transfer process relying on the interfacial area. In this study, lipase-immobilized mesoporous silica particles (LMSPs) are employed as both Pickering stabilizers and biocatalysts. A series of alkyl silanes with the different carbon length are used to modify LMSPs to obtain suitable wettability and enlarge the interfacial area of Pickering emulsion. The results show the water/paraffin oil Pickering emulsions stabilized by 8 carbon atoms silane grafted LMSPs (LMSPs_C8) with a three-phase contact angles of 95° get the relatively large interfacial area. Moreover, the conversion of enzymatic reaction catalyzed by LMSPs_C8 Pickering emulsion system is 3.4 times higher than that unmodified LMSPs with the reaction time of 10 min. Additionally, the effective recycling of LMSPs is achieved by simple low-speed centrifugation. As evidenced by a 6-cycles reaction of remaining 75% of relative enzymatic activity, the protection of 350–450 nm mesoporous silica particles can alleviate the inactivation of enzyme from the shear stress and make a benefit to form stabile Pickering emulsion. Therefore, the biphasic reactions in the Pickering emulsion system can be effectively enhanced through changing interfacial area only by the means of adjusting the wettability of biocatalysts. Full article

(This article belongs to the Special Issue Biocatalysts: Design and Application)

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12 pages, 1929 KiB

Open AccessArticle

Study on Transglucosylation Properties of Amylosucrase from Xanthomonas campestris pv. Campestris and Its Application in the Production of α-Arbutin

by Chengyu Yang, Weiming Fan, Ruijie Zhang, Jiping Shi, Zorica Knežević-Jugović and Baoguo Zhang

Catalysts 2019, 9(1), 5; https://doi.org/10.3390/catal9010005 - 21 Dec 2018

Cited by 17 | Viewed by 4210

Abstract

α-Arbutin (4-hydroquinone-α-D-glucopyranoside), an effective skin-lightening agent due to its considerable inhibitory effect on human tyrosinase activity, is widely used in the pharmaceutical and cosmetic industries. Recently, α-arbutin was prepared through transglucosylation of hydroquinone using microbial glycosyltransferases as catalysts. However, the low yield and [...] Read more.

α-Arbutin (4-hydroquinone-α-D-glucopyranoside), an effective skin-lightening agent due to its considerable inhibitory effect on human tyrosinase activity, is widely used in the pharmaceutical and cosmetic industries. Recently, α-arbutin was prepared through transglucosylation of hydroquinone using microbial glycosyltransferases as catalysts. However, the low yield and prolonged reaction time of the biotransformation process of α-arbutin production limited its industrial application. In this work, an amylosucrase (ASase) from Xanthomonas campestris pv. campestris str. ATCC 33913 (XcAS) was expressed efficiently in Escherichia coli JM109. The catalytic property of the purified XcAS for the synthesis of α-arbutin was tested. The recombinant strain was applied for highly efficient synthesis of α-arbutin using sucrose and hydroquinone as glucosyl donor and acceptor, respectively. By optimizing the biotransformation conditions and applying a fed-batch strategy, the final production yield and conversion rate of α-arbutin reached 60.9 g/L and 95.5%, respectively, which is the highest reported yield by engineered strains. Compared to the highest reported value (<1.4 g/L/h), our productivity (7.6 g/L/h) was improved more than five-fold. This work represents an efficient and rapid method for α-arbutin production with potential industrial applications. Full article

(This article belongs to the Special Issue Biocatalysts: Design and Application)

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12 pages, 3712 KiB

Open AccessArticle

Highly Efficient Synthesis of 2,5-Dihydroxypyridine using Pseudomonas sp. ZZ-5 Nicotine Hydroxylase Immobilized on Immobead 150

by Caiwen Dong, Yadong Zheng, Hongzhi Tang, Zhangde Long, Jigang Li, Zhiping Zhang, Sumeng Liu, Duobin Mao and Tao Wei

Catalysts 2018, 8(11), 548; https://doi.org/10.3390/catal8110548 - 16 Nov 2018

Cited by 2 | Viewed by 3156

Abstract

In this report, the use of immobilized nicotine hydroxylase from Pseudomonas sp. ZZ-5 (HSPH_ZZ) for the production of 2,5-dihydroxypyridine (2,5-DHP) from 6-hydroxy-3-succinoylpyridine (HSP) in the presence of nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) is described. HSPH_ZZ was [...] Read more.

In this report, the use of immobilized nicotine hydroxylase from Pseudomonas sp. ZZ-5 (HSPH_ZZ) for the production of 2,5-dihydroxypyridine (2,5-DHP) from 6-hydroxy-3-succinoylpyridine (HSP) in the presence of nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) is described. HSPH_ZZ was covalently immobilized on Immobead 150 (ImmHSPH_ZZ). ImmHSPH_ZZ (obtained with 5–30 mg of protein per gram of support) catalyzed the hydrolysis of HSP to 2,5-DHP. At a protein loading of 15 mg g⁻¹, ImmHSPH_ZZ converted 93.6% of HSP to 2,5-DHP in 6 h. The activity of ImmHSPH_ZZ was compared with that of free HSPH_ZZ under various conditions, including pH, temperature, enzyme concentration, substrate concentration and stability over time, and kinetic parameters were measured. The results showed that ImmHSPH_ZZ performed better over wider ranges of pH and temperature when compared with that of HSPH_ZZ. The optimal concentrations of ImmHSPH_ZZ and substrate were 30 mg L⁻¹ and 0.75 mM, respectively. Under optimal conditions, 94.5 mg L⁻¹ of 2,5-DHP was produced after 30 min with 85.4% conversion. After 8 reaction cycles and 6 days of storage, 51.3% and 75.0% of the initial enzyme activity remained, respectively. The results provide a framework for development of commercially suitable immobilized enzymes that produce 2,5-DHP. Full article

(This article belongs to the Special Issue Biocatalysts: Design and Application)

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15 pages, 1002 KiB

Open AccessArticle

Production of Thermostable T1 Lipase Using Agroindustrial Waste Medium Formulation

by Hisham Mohd Nooh, Malihe Masomian, Abu Bakar Salleh, Rosfarizan Mohamad, Mohd Shukuri Mohamad Ali and Raja Noor Zaliha Raja Abd Rahman

Catalysts 2018, 8(11), 485; https://doi.org/10.3390/catal8110485 - 23 Oct 2018

Cited by 7 | Viewed by 2924

Abstract

Large-scale production of T1 lipase using conventional culture media is costly. To reduce the cost of production, an alternative growth medium using local resources has been developed. In this study, the growth of recombinant Escherichia coli and expression of T1 lipase were tested [...] Read more.

Large-scale production of T1 lipase using conventional culture media is costly. To reduce the cost of production, an alternative growth medium using local resources has been developed. In this study, the growth of recombinant Escherichia coli and expression of T1 lipase were tested using different agroindustrial wastes as carbon and nitrogen sources by conventional method. Subsequently, by using central composite rotatable design (CCRD), a set of 30 experiments was generated to evaluate the effect of different parameters, including the amount of molasses (as carbon source), fish waste (as nitrogen source), NaCl, and inducer concentration on production of T1 lipase. Response surface methodology (RSM) analysis indicated that all factors had significant effects on T1 lipase production. This statistical analysis was utilised to develop a quadratic model to correlate various important variables for the growth of the recombinant strain and regulation of gene expression to the response (T1 lipase activity). Optimum conditions for T1 lipase production were observed to be 1.0 g/L of molasses, 2.29 g/L of fish waste, 3.46 g/L of NaCl, and 0.03 mM of IPTG (Isopropyl β-d-1-thiogalactopyranoside). Based on these conditions, the actual lipase activity was found to be 164.37 U/mL, which fitted well with the maximum predicted value of 172.89 U/mL. Therefore, the results demonstrated that, the statistical analysis, performed using RSM, was efficient in optimising T1 lipase production. Moreover, the optimum conditions obtained can be applied to scale up the process and minimise the cost of enzyme production. Full article

(This article belongs to the Special Issue Biocatalysts: Design and Application)

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8 pages, 953 KiB

Open AccessCommunication

Application of Lecitase^® Ultra-Catalyzed Hydrolysis to the Kinetic Resolution of (E)-4-phenylbut-3-en-2-yl Esters

by Aleksandra Leśniarek, Anna Chojnacka and Witold Gładkowski

Catalysts 2018, 8(10), 423; https://doi.org/10.3390/catal8100423 - 28 Sep 2018

Cited by 12 | Viewed by 4280

Abstract

The possibility of using Lecitase^® Ultra as a novel alternative biocatalyst for the kinetic resolution of model racemic allyl esters of (E)-4-phenylbut-3-en-3-ol: Acetate (4a) and propionate (4b) through their enantioselective hydrolysis was investigated. Reaction afforded (+)-( [...] Read more.

The possibility of using Lecitase^® Ultra as a novel alternative biocatalyst for the kinetic resolution of model racemic allyl esters of (E)-4-phenylbut-3-en-3-ol: Acetate (4a) and propionate (4b) through their enantioselective hydrolysis was investigated. Reaction afforded (+)-(R)-alcohol (3) and unreacted (−)-(S)-ester (4a or 4b). Hydrolysis of propionate 4b proceeded with higher enantioselectivity than acetate 4a. (R)-Alcohol (3) with highest enantiomeric excess (93–99%) was obtained at 20–30 °C by hydrolysis of propionate 4b, while the highest optical purity of unreacted substrate was observed for (S)-acetate 4a (ee = 34–56%). The highest enantioselectivity was found for the hydrolysis of propionate 4b catalyzed at 30 °C (E = 38). Reaction carried out at 40 °C significantly lowered enantiomeric excess of produced alcohol 3 and enantioselectivity in resolution. Lecitase^® Ultra catalyzed the enantioselective hydrolysis of allyl esters 4a,b according to Kazlauskas’ rule to produce (R)-alcohol 3 and can find application as a novel biocatalyst in the processes of kinetic resolution of racemic allyl esters. Full article

(This article belongs to the Special Issue Biocatalysts: Design and Application)

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14 pages, 5279 KiB

Open AccessArticle

Study of Extraction and Enzymatic Properties of Cell-Envelope Proteinases from a Novel Wild Lactobacillus plantarum LP69

by He Chen, Jie Huang, Binyun Cao, Li Chen, Na Song and Ni Lei

Catalysts 2018, 8(8), 325; https://doi.org/10.3390/catal8080325 - 8 Aug 2018

Cited by 7 | Viewed by 3575

Abstract

Lactobacilli cell-envelope proteinases (CEPs) have been widely used in the development of new streams of blockbuster nutraceuticals because of numerous biopharmaceutical potentials; thus, the development of viable methods for CEP extraction and the improvement of extraction efficiency will promote their full-scale application. In [...] Read more.

Lactobacilli cell-envelope proteinases (CEPs) have been widely used in the development of new streams of blockbuster nutraceuticals because of numerous biopharmaceutical potentials; thus, the development of viable methods for CEP extraction and the improvement of extraction efficiency will promote their full-scale application. In this study, CEP from a novel wild Lactobacillus plantarum LP69 was released from cells by incubating in calcium-free buffer. The extraction conditions of CEP were optimized by response surface methodology with the enzyme activity and specific activity as the detective marker. The optimal extraction conditions were: time of 80 min, temperature of 39 °C and buffer pH of 6.5. Under these conditions, enzyme activity and specific activity were (23.94 ± 0.86) U/mL and (1.37 ± 0.03) U/mg, respectively, which were well matched with the predicted values (22.12 U/mL and 1.36 U/mg). Optimal activity of the crude CEP occurred at pH 8.0 and 40 °C. It is a metallopeptidase, activated by Ca²⁺, inhibited by Zn²⁺ and ethylene-diamine-tetra-acetic acid, and a serine proteinase which is inhibited by phenylmethylsulfonyl fluoride. Kinetic studies showed that CEP from LP69 could hydrolyze whey protein, lactoglobulin and casein. Our study improves the extraction efficiency of CEPs from LP69, providing the reference for their industrial development. Full article

(This article belongs to the Special Issue Biocatalysts: Design and Application)

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13 pages, 5960 KiB

Open AccessArticle

Electrochemical Biosensor for the Determination of Amlodipine Besylate Based on Gelatin–Polyaniline Iron Oxide Biocomposite Film

by Elbahi Djaalab, Mohamed El Hadi Samar, Saida Zougar and Rochdi Kherrat

Catalysts 2018, 8(6), 233; https://doi.org/10.3390/catal8060233 - 4 Jun 2018

Cited by 19 | Viewed by 6226

Abstract

In the present study, a new biosensor based on lipase from Candida rugosa (CRL) was developed for amlodipine besylate drug (AMD) with biodegradable material using a mixture of polyaniline iron oxide and gelatin. Polyaniline/Fe₂O₃ (PANI@Fe₂O₃) was [...] Read more.

In the present study, a new biosensor based on lipase from Candida rugosa (CRL) was developed for amlodipine besylate drug (AMD) with biodegradable material using a mixture of polyaniline iron oxide and gelatin. Polyaniline/Fe₂O₃ (PANI@Fe₂O₃) was prepared by a chemical polymerization method in a medium of ammonium persulfate as an oxidant and characterized by employing Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR), and Ultra-violet (UV) spectroscopy. The purified enzyme was entrapped in the biocomposite matrix film with the aid of a glutaraldehyde cross-linking reagent to establish the immobilization of the lipase. The principle of the biosensor is based on the electrochemical properties of amlodipine besylate (AMD), which were studied for the first time using the cyclic voltammetric method. The cathodic behavior of AMD was measured on the irreversible reduction signal at −0.185 V versus Ag/AgCl at pH 7.4 and 30 °C in a phosphate alkaline buffer. Full article

(This article belongs to the Special Issue Biocatalysts: Design and Application)

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Review

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19 pages, 962 KiB

Open AccessReview

Advanced Rhodococcus Biocatalysts for Environmental Biotechnologies

by Anastasiia Krivoruchko, Maria Kuyukina and Irena Ivshina

Catalysts 2019, 9(3), 236; https://doi.org/10.3390/catal9030236 - 4 Mar 2019

Cited by 54 | Viewed by 6954

Abstract

The review is devoted to biocatalysts based on actinobacteria of the genus Rhodococcus, which are promising for environmental biotechnologies. In the review, biotechnological advantages of Rhodococcus bacteria are evaluated, approaches used to develop robust and efficient biocatalysts are discussed, and their relevant [...] Read more.

The review is devoted to biocatalysts based on actinobacteria of the genus Rhodococcus, which are promising for environmental biotechnologies. In the review, biotechnological advantages of Rhodococcus bacteria are evaluated, approaches used to develop robust and efficient biocatalysts are discussed, and their relevant applications are given. We focus on Rhodococcus cell immobilization in detail (methods of immobilization, criteria for strains and carriers, and optimization of process parameters) as the most efficient approach for stabilizing biocatalysts. It is shown that advanced Rhodococcus biocatalysts with improved working characteristics, enhanced stress tolerance, high catalytic activities, human and environment friendly, and commercially viable are developed, which are suitable for wastewater treatment, bioremediation, and biofuel production. Full article

(This article belongs to the Special Issue Biocatalysts: Design and Application)

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Other

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31 pages, 2948 KiB

Open AccessFeature PaperPerspective

CLEAs, Combi-CLEAs and ‘Smart’ Magnetic CLEAs: Biocatalysis in a Bio-Based Economy

by Roger A. Sheldon

Catalysts 2019, 9(3), 261; https://doi.org/10.3390/catal9030261 - 14 Mar 2019

Cited by 121 | Viewed by 9350

Abstract

Biocatalysis has emerged in the last decade as a pre-eminent technology for enabling the envisaged transition to a more sustainable bio-based economy. For industrial viability it is essential that enzymes can be readily recovered and recycled by immobilization as solid, recyclable catalysts. One [...] Read more.

Biocatalysis has emerged in the last decade as a pre-eminent technology for enabling the envisaged transition to a more sustainable bio-based economy. For industrial viability it is essential that enzymes can be readily recovered and recycled by immobilization as solid, recyclable catalysts. One method to achieve this is via carrier-free immobilization as cross-linked enzyme aggregates (CLEAs). This methodology proved to be very effective with a broad selection of enzymes, in particular carbohydrate-converting enzymes. Methods for optimizing CLEA preparations by, for example, adding proteic feeders to promote cross-linking, and strategies for making the pores accessible for macromolecular substrates are critically reviewed and compared. Co-immobilization of two or more enzymes in combi-CLEAs enables the cost-effective use of multiple enzymes in biocatalytic cascade processes and the use of “smart” magnetic CLEAs to separate the immobilized enzyme from other solids has raised the CLEA technology to a new level of industrial and environmental relevance. Magnetic-CLEAs of polysaccharide-converting enzymes, for example, are eminently suitable for use in the conversion of first and second generation biomass. Full article

(This article belongs to the Special Issue Biocatalysts: Design and Application)

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