Candida antarctica Lipase B: An Ideal Biocatalyst for the Preparation of Nitrogenated Organic Compounds

Enzymes from Marine Polar Regions and Their Biotechnological Applications

The microorganisms that evolved at low temperatures express cold-adapted enzymes endowed with unique catalytic properties in comparison to their mesophilic homologues, i.e., higher catalytic efficiency, improved flexibility, and lower thermal stability. Cold environments are therefore an attractive research area for the discovery of enzymes to be used for investigational and industrial applications in which such properties are desirable. In this work, we will review the literature on cold-adapted enzymes specifically focusing on those discovered in the bioprospecting of polar marine environments, so far largely neglected because of their limited accessibility. We will discuss their existing or proposed biotechnological applications within the framework of the more general applications of cold-adapted enzymes.

Nanobiohybrids: a new concept for metal nanoparticles synthesis

In recent years, nanoscience and nanotechnology have brought a great revolution in different areas. In particular, the synthesis of transition metal nanoparticles has been of great relevance for their use in areas such as biomedicine, antimicrobial properties or catalytic applications for chemical synthesis. Recently, an innovative straightforward and very efficient synthesis of these nanoparticles by simply using enzymes as inductors in aqueous media has been described. This represents a very green alternative to the different methodologies described in the literature for metal nanoparticles preparation where harsh conditions are necessary. In this review the most recent advances in the synthesis of metal nanoparticles by this green technology, explaining the synthetic mechanism, the role of the enzyme in the formation of the nanoparticles and the effect on the final properties of these nanoparticles, are summarised. The application of these novel metal nanoparticles-enzyme hybrids in synthetic chemistry as heterogeneous catalysts with metal or dual (enzymatic and metallic) activity and their capacity as environmental and antimicrobial agents have also been discussed.

Directly covalent immobilization of Candida antarctica lipase B on oxidized aspen powder by introducing poly‑lysines: An economical approach to improve enzyme performance

In our previous study, we could achieve high soluble expression of Candida antarctica lipase B (CalB) in E. coli by fusion poly‑amino acid tags on CalB (pCalB). Herein, we are surprised to find that pCalB can be easily and directly covalent binding on a simply oxidized aspen powder (OAP) by the aid of poly‑lysine tags. Under the optimal conditions, 72.9 ± 3.6% of the total protein could be immobilized, and the activity recovery of immobilized pCalB (pCalB-OAP) was 98.9 ± 3.8%. The analysis of scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) indicated that OAP was a suitable carrier for enzyme immobilization. The immobilized pCalB-OAP could exhibit excellent thermal stabilities, and it retained a residual activity of 58.4 ± 2.8% at 55 °C, whereas only 21.2 ± 2.2% of its initial activity for free pCalB was observed. And it could also display a nice tolerance for the changes of pH environment, compared with that of free pCalB. The results that pCalB-OAP could retained 73.6 ± 2.9% of their initial activity in (R, S)-NEMPAME hydrolysis after the tenth cycles, suggested that pCalB-OAP could be effectively recycled. The immobilization strategies established here were simple and inexpensive.

Increase of Candida antarctica lipase B production under PGK promoter in Pichia pastoris: effect of multicopies

The effect of gene dosage on the production of Candida antarctica lipase B (CalB) in the methylotrophic yeast Komagataella phaffii, at high densities in a simple medium containing crude glycerin as the sole carbon source, is described. The use of crude glycerin, the main by-product of biodiesel production from vegetable oils, will reduce the production cost of the bioprocess. Two K. phaffii strains were constructed with one or three copies of LipB, an optimized version of the gene encoding CalB under the control of the constitutive P_PGK1 promoter. These two constructs were tested and compared on batches using minimal-salts medium with crude glycerin. The strain with three copies achieved a higher enzyme yield (48,760 U/L, 2.3-fold higher than the one-copy strain), with 42 g/L biomass, with no effects on growth.

Enzyme immobilized millimeter-sized polyHIPE beads with easy separability and recyclability

Enzyme immobilized reusable millimeter-sized beads were prepared through covalently immobilizing Candida antarctica lipase B onto emulsion-templated porous beads.

Novozym 435: the “perfect” lipase immobilized biocatalyst?

Novozym 435 (N435) is a commercially available immobilized lipase produced by Novozymes with its advantages and drawbacks.

Application of lipase bearing dead mycelia as biocatalyst for octyl-octanoate synthesis

ABSTRACT

The present study scrutinizes lipases of different origins, immobilization methods, carriers, and reaction solvents to accelerate the octyl octanoate synthesis. The acylation reaction parameters including temperature, moisture level, shaking speed and enzyme dose were subsequently investigated and optimized following fully rotatable central composite design. The initial screening revealed that lipases of Rhizopus arrhizus, when applied as a biocatalyst (lipase bearing dead mycelia) furnished the highest acylation activity (147 μM L-1 min-1). Validation of reaction conditions disclosed that 250 I.U. of lipase based biocatalyst when incubated with 850 mM of acylating agent and 750 mM of the substrate at 35 °C, 3% moisture level and 150 RPM shaking speed produced 70% acylation yield with an acylation activity higher than 147 μM L-1 min-1. The observed results certify that lipase bearing dead mycelia of R. arrhizus might be an intelligent biocatalyst to manipulate the yield of acylation reactions encountered in the food industry.

GRAPHICAL ABSTRACT

Immobilization on octyl-agarose beads and some catalytic features of commercial preparations of lipase a from Candida antarctica (Novocor ADL): Comparison with immobilized lipase B from Candida antarctica

Lipase A from Candida antarctica (CALA, commercialized as Novocor ADL) was immobilized on octyl-agarose, which is a very useful support for lipase immobilization, and coated with polyethylenimine to improve the stability. The performance was compared to that of the form B of the enzyme (CALB) immobilized on the same support, as both enzymes are among the most popular ones used in biocatalysis. CALA immobilization produced a significant increase in enzyme activity vs. p-nitrophenyl butyrate (pNPB) (by a factor of seven), and the coating with PEI did not have a significant effect on enzyme activity. CALB reduced its activity slightly after enzyme immobilization. Octyl-CALA was less stable than octyl-CALB at pH 9 and more stable at pH 5 and, more clearly, at pH 7. PEI coating only increased octyl-CALA stability at pH 9. In organic solvents, CALB had much better stability in methanol and was similarly stable in acetonitrile or dioxane. In these systems, the PEI coating of octyl-CALA permitted some stabilization. While octyl-CALA was more active vs. pNPB, octyl-CALB was much more active vs. mandelic esters or triacetin. Thus, depending on the specific reaction and the conditions, CALA or CALB may offer different advantages and drawbacks. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2735, 2019.

Immobilization of Eversa Lipase on Octyl Agarose Beads and Preliminary Characterization of Stability and Activity Features

Eversa is an enzyme recently launched by Novozymes to be used in a free form as biocatalyst in biodiesel production. This paper shows for first time the immobilization of Eversa (a commercial lipase) on octyl and aminated agarose beads and the comparison of the enzyme properties to those of the most used lipase, the isoform B from Candida antarctica (CALB) immobilized on octyl agarose beads. Immobilization on octyl and aminated supports of Eversa has not had a significant effect on enzyme activity versus p-nitrophenyl butyrate (pNPB) under standard conditions (pH 7), but immobilization on octyl agarose beads greatly enhanced the stability of the enzyme under all studied conditions, much more than immobilization on aminated support. Octyl-Eversa was much more stable than octyl-CALB at pH 9, but it was less stable at pH 5. In the presence of 90% acetonitrile or dioxane, octyl-Eversa maintained the activity (even increased the activity) after 45 days of incubation in a similar way to octyl-CALB, but in 90% of methanol, results are much worse, and octyl-CALB became much more stable than Eversa. Coating with PEI has not a clear effect on octyl-Eversa stability, although it affected enzyme specificity and activity response to the changes in the pH. Eversa immobilized octyl supports was more active than CALB versus triacetin or pNPB, but much less active versus methyl mandelate esters. On the other hand, Eversa specificity and response to changes in the medium were greatly modulated by the immobilization protocol or by the coating of the immobilized enzyme with PEI. Thus, Eversa may be a promising biocatalyst for many processes different to the biodiesel production and its properties may be greatly improved following a suitable immobilization protocol, and in some cases is more stable and active than CALB.

Screening, purification and characterization of lipase from Burkholderia pyrrocinia B1213

A lipase producing strain B1213 isolated from soil was identified as Burkholderia pyrrocinia based on 16S rRNA gene and recA sequeence analysis, making this the first report on the presence of a lipase from B. pyrrocinia. Under an aqueous two-phase purification strategy, which included (ATPE)-ion-exchange chromatography (IEC)-gel and filtration chromatography (GFC), the specific activity of the 35-kDa lipase was determined to be 875.7 U/mg protein. The optimum pH and temperature of this lipase was pH 8.0 and 50 °C, respectively. The lipase retained > 85% activity in isopropanol and acetone at 30 °C for 10 min but the activity was reduced to 10.6% in n-hexane. Mg²⁺, Al³⁺, Mn²⁺, and Fe³⁺ enhanced lipase activity at both 1 mM and 5 mM concentrations. p-NPP, a long-chain acyl group 4-NP ester, appeared to be a good substrate candidate.

Sequence-Based In-silico Discovery, Characterisation, and Biocatalytic Application of a Set of Imine Reductases

Imine reductases (IREDs) have recently become a primary focus of research in biocatalysis, complementing other classes of amine-forming enzymes such as transaminases and amine dehydrogenases. Following in the footsteps of other research groups, we have established a set of IRED biocatalysts by sequence-based in silico enzyme discovery. In this study, we present basic characterisation data for these novel IREDs and explore their activity and stereoselectivity using a panel of structurally diverse cyclic imines as substrates. Specific activities of >1 U/mg and excellent stereoselectivities (ee>99 %) were observed in many cases, and the enzymes proved surprisingly tolerant towards elevated substrate loadings. Co-expression of the IREDs with an alcohol dehydrogenase for cofactor regeneration led to whole-cell biocatalysts capable of efficiently reducing imines at 100 mM initial concentration with no need for the addition of extracellular nicotinamide cofactor. Preparative biotransformations on gram scale using these 'designer cells' afforded chiral amines in good yield and excellent optical purity.

Enantioselective Synthesis of All-Carbon Quaternary Centers Structurally Related to Amaryllidaceae Alkaloids

Enantioselective synthesis of all-carbon quaternary centers remains a considerable challenge for synthetic organic chemists. Here, we report a two-step protocol to synthesize such centers including tandem cyclization/Suzuki cross-coupling followed by halocarbocyclization. During this process, two rings, three new C-C bonds and a stereochemically defined all-carbon quaternary center are formed. The absolute configuration of this center is controlled by the stereochemistry of the adjacent stereocenter, which derives from an appropriate enantioenriched starting material. Using this method, we synthesized polycyclic compounds structurally similar to Amaryllidaceae alkaloids in high enantiomeric excesses. Because these products resemble naturally occurring compounds, our protocol can be used to synthesize various potentially bioactive compounds.

Modulation of the Catalytic Properties of Lipase B from Candida antarctica by Immobilization on Tailor-Made Magnetic Iron Oxide Nanoparticles: The Key Role of Nanocarrier Surface Engineering

The immobilization of biocatalysts on magnetic nanomaterial surface is a very attractive alternative to achieve enzyme nanoderivatives with highly improved properties. The combination between the careful tailoring of nanocarrier surfaces and the site-specific chemical modification of biomacromolecules is a crucial parameter to finely modulate the catalytic behavior of the biocatalyst. In this work, a useful strategy to immobilize chemically aminated lipase B from Candida antarctica on magnetic iron oxide nanoparticles (IONPs) by covalent multipoint attachment or hydrophobic physical adsorption upon previous tailored engineering of nanocarriers with poly-carboxylic groups (citric acid or succinic anhydride, CALBEDA@CA-NPs and CALBEDA@SA-NPs respectively) or hydrophobic layer (oleic acid, CALBEDA@OA-NPs) is described. After full characterization, the nanocatalysts have been assessed in the enantioselective kinetic resolution of racemic methyl mandelate. Depending on the immobilization strategy, each enzymatic nanoderivative permitted to selectively improve a specific property of the biocatalyst. In general, all the immobilization protocols permitted loading from good to high lipase amount (149 < immobilized lipase < 234 mg/gFe). The hydrophobic CALBEDA@OA-NPs was the most active nanocatalyst, whereas the covalent CALBEDA@CA-NPs and CALBEDA@SA-NPs were revealed to be the most thermostable and also the most enantioselective ones in the kinetic resolution reaction (almost 90% ee R-enantiomer). A strategy to maintain all these properties in long-time storage (up to 1 month) by freeze-drying was also optimized. Therefore, the nanocarrier surface engineering is demonstrated to be a key-parameter in the design and preparation of lipase libraries with enhanced catalytic properties.

Chemoenzymatic Approaches to the Synthesis of the Calcimimetic Agent Cinacalcet Employing Transaminases and Ketoreductases

Several chemoenzymatic routes have been explored for the preparation of cinacalcet, a calcimimetic agent. Transaminases (TAs) and ketoreductases (KREDs) turned out to be useful biocatalysts for the preparation of key optically active precursors. Thus, the asymmetric amination of 1-acetonaphthone yielded an enantiopure (R)-amine, which can be alkylated in one step to yield cinacalcet. Alternatively, the bioreduction of the same ketone resulted in an enantiopure (S)-alcohol, which was easily converted into the previous (R)-amine. In addition, the reduction was efficiently performed with the KRED and its cofactor co-immobilized on the same porous surface. This self-sufficient heterogeneous biocatalyst presented an accumulated total turnover number (TTN) for the cofactor of 675 after 5 consecutive operational cycles. Finally, in a preparative scale synthesis the TA-based approach was performed in aqueous medium and led to enantiopure cinacalcet in two steps and 50% overall yield.

Promiscuous activity of C-acyltransferase from Pseudomonas protegens: synthesis of acetanilides in aqueous buffer

A C-acyltransferase was found to show promiscuous activity catalyzing C–N bond formation in aqueous buffer instead of C–C bond formation.

Amide bond formation has considerable significance in synthetic chemistry. Although the C-acyltransferase from Pseudomonas protegens has been found to catalyze C–C bond formation in nature as well as in in vitro experiments with non-natural substrates, it is now shown that the enzyme is also able to catalyze amide formation using aniline derivatives as substrates with promiscuous activity. Importantly, the amide formation was enabled in aqueous buffer. Identifying phenyl acetate as the most suitable acetyl donor, the products were obtained with up to >99% conversion and up to 99% isolated yield.

Enzymatic amidation for industrial applications

Nature has developed a robust toolbox for the formation of amide bonds, enabling a variety of disconnections applicable to small molecule synthesis. In spite of this, the exploitation of biocatalytic techniques for industrial synthesis remains limited to a few very important cases. This review discusses previously demonstrated techniques for the biocatalytic synthesis of amide bonds, reviews examples of industrial scale-up of these techniques, and identifies a number of limitations to the scalability within the current state of the art.

Ultrasound-assisted lipase catalyzed hydrolysis of aspirin methyl ester

The ultrasound-assisted hydrolysis of aspirin methyl ester (AME) was investigated using immobilized Candida antarctica lipase B (CALB) (1%) in the presence of solvents like triolein, chloroform (CHCl₃) and dichloromethane (DCM). The effect of ultrasound and the role of water on the conversion rates have also been investigated. Proton nuclear magnetic resonance spectroscopic (¹H NMR) was chosen to calculate hydrolysis convertion rates. We observed that lipase-ultrasound assisted hydrolysis of AME in the presence of triolein and water showed the highest hydrolysis conversion rate (65.3%). Herein low water amount played an important role as a nucleophile being crucial for the hydrolysis yields obtained. Lipase activity was affected by the conjugated action of ultrasound and solvents (35.75% of decrease), however not disturbing its hydrolytic efficiency. It was demonstrated that lipase is able to hydrolyse AME to methyl 2-hydroxy benzoate (methyl salicylate), which applications include fragrance agents in food, beverages and cosmetics, or analgesic agent in liniments.

Impact of signal peptide and transmembrane segments on expression and biochemical properties of a lipase from Bacillus sphaericus 205y

A total of 97 amino acids, considered as the signal peptide and transmembrane segments were removed from 205y lipase gene using polymerase chain reaction technique that abolished the low activity of this enzyme. The mature enzyme was expressed in Escherichia coli using pBAD expression vector, which gave up to a 13-fold increase in lipase activity. The mature 205y lipase (without signal peptide and transmembrane; -SP/TM) was purified to homogeneity using the isoelectric focusing technique with 53% recovery. Removing of the signal peptide and transmembrane segments had resulted in the shift of optimal pH, an increase in optimal temperature and tolerance towards more water-miscible organic solvents as compared to the characteristics of open reading frame (ORF) of 205y lipase. Also, in the presence of 1mM inhibitors, less decrease in the activity of mature 205y lipase was observed compared to the ORF of the enzyme. Protein structure modeling showed that 205y lipase consisted of an α/β hydrolase fold without lid domain. However, the transmembrane segment could effect on the enzyme activity by covering the active site or aggregation the protein.

Enhanced production of a diastereomer type of mannosylerythritol lipid-B by the basidiomycetous yeast Pseudozyma tsukubaensis expressing lipase genes from Pseudozyma antarctica

Basidiomycetous yeasts in the genus Pseudozyma are known to produce extracellular glycolipids called mannosylerythritol lipids (MELs). Pseudozyma tsukubaensis produces a large amount of MEL-B using olive oil as the sole carbon source (> 70 g/L production). The MEL-B produced by P. tsukubaensis is a diastereomer type of MEL-B, which consists of 4-O-β-D-mannopyranosyl-(2R,3S)-erythritol as a sugar moiety, in contrast to the conventional type of MELs produced by P. antarctica, which contain 4-O-β-D mannopyranosyl-(2S,3R)-erythritol. In this study, we attempted to increase the production of the diastereomer type of MEL-B in P. tsukubaensis 1E5 by introducing the genes encoding two lipases, PaLIPAp (PaLIPA) and PaLIPBp (PaLIPB) from P. antarctica T-34. Strain 1E5 expressing PaLIPA exhibited higher lipase activity than the strain possessing an empty vector, which was used as a negative control. Strains of 1E5 expressing PaLIPA or PaLIPB showed 1.9- and 1.6-fold higher MEL-B production than the negative control strain, respectively, and oil consumption was also accelerated by the introduction of these lipase genes. MEL-B production was estimated using time course analysis in the recombinant strains. Strain 1E5 expressing PaLIPA produced 37.0 ± 1.2 g/L of MEL-B within 4 days of cultivation, whereas the strain expressing an empty vector produced 22.1 ± 7.5 g/L in this time. Overexpression of PaLIPA increased MEL-B production by P. tsukubaensis strain 1E5 from olive oil as carbon source by more than 1.7-fold.

Synthesis of Geraniol Esters in a Continuous-Flow Packed-Bed Reactor of Immobilized Lipase: Optimization of Process Parameters and Kinetic Modeling

With increasing demand for perfumes, flavors, beverages, and pharmaceuticals, the various associated industries are resorting to different approaches to enhance yields of desired compounds. The use of fixed-bed biocatalytic reactors in some of the processes for making fine chemicals will be of great value because the reaction times could be reduced substantially as well as high conversion and yields obtained. In the current study, a continuous-flow packed-bed reactor of immobilized Candida antarctica lipase B (Novozym 435) was employed for synthesis of various geraniol esters. Optimization of process parameters such as biocatalyst screening, effect of solvent, mole ratio, temperature and acyl donors was studied in a continuous-flow packed-bed reactor. Maximum conversion of ~ 87% of geranyl propionate was achieved in 15 min residence time at 70 °C using geraniol and propionic acid with a 1:1 mol ratio. Novozym 435 was found to be the most active and stable biocatalyst among all tested. Ternary complex mechanism with propionic acid inhibition was found to fit the data.

In vivo plug-and-play: a modular multi-enzyme single-cell catalyst for the asymmetric amination of ketoacids and ketones

Background

Transaminases have become a key tool in biocatalysis to introduce the amine functionality into a range of molecules like prochiral α-ketoacids and ketones. However, due to the necessity of shifting the equilibrium towards the product side (depending on the amine donor) an efficient amination system may require three enzymes. So far, this well-established transformation has mainly been performed in vitro by assembling all biocatalysts individually, which comes along with elaborate and costly preparation steps. We present the design and characterization of a flexible approach enabling a quick set-up of single-cell biocatalysts producing the desired enzymes. By choosing an appropriate co-expression strategy, a modular system was obtained, allowing for flexible plug-and-play combination of enzymes chosen from the toolbox of available transaminases and/or recycling enzymes tailored for the desired application.

Results

By using a two-plasmid strategy for the recycling enzyme and the transaminase together with chromosomal integration of an amino acid dehydrogenase, two enzyme modules could individually be selected and combined with specifically tailored E. coli strains. Various plug-and-play combinations of the enzymes led to the construction of a series of single-cell catalysts suitable for the amination of various types of substrates. On the one hand the fermentative amination of α-ketoacids coupled both with metabolic and non-metabolic cofactor regeneration was studied, giving access to the corresponding α-amino acids in up to 96% conversion. On the other hand, biocatalysts were employed in a non-metabolic, “in vitro-type” asymmetric reductive amination of the prochiral ketone 4-phenyl-2-butanone, yielding the amine in good conversion (77%) and excellent stereoselectivity (ee = 98%).

Conclusions

The described modularized concept enables the construction of tailored single-cell catalysts which provide all required enzymes for asymmetric reductive amination in a flexible fashion, representing a more efficient approach for the production of chiral amines and amino acids.

Electronic supplementary material

The online version of this article (doi:10.1186/s12934-017-0750-5) contains supplementary material, which is available to authorized users.

NAD(P)H-Dependent Dehydrogenases for the Asymmetric Reductive Amination of Ketones: Structure, Mechanism, Evolution and Application

Asymmetric reductive aminations are some of the most important reactions in the preparation of active pharmaceuticals, as chiral amines feature in many of the world's most important drugs. Although many enzymes have been applied to the synthesis of chiral amines, the development of reductive amination reactions that use enzymes is attractive, as it would permit the one-step transformation of readily available prochiral ketones into chiral amines of high optical purity. However, as most natural "reductive aminase" activities operate on keto acids, and many are able to use only ammonia as the amine donor, there is considerable scope for the engineering of natural enzymes for the reductive amination of ketones, and also for the preparation of secondary amines using alkylamines as donors. This review summarises research into the development of NAD(P)H-dependent dehydrogenases for the reductive amination of ketones, including amino acid dehydrogenases (AADHs), natural amine dehydrogenases (AmDHs), opine dehydrogenases (OpDHs) and imine reductases (IREDs). In each case knowledge of the structure and mechanism of the enzyme class is addressed, with a further description of the engineering of those enzymes for the reductive amination of ketones towards primary and also secondary amine products.