Lipase applications in oil hydrolysis with a case study on castor oil: a review

Plants lipases: challenges, recent advances, and future prospects - a review

Plant lipases offer a sustainable and promising alternative for various industrial applications, with increasing use in biocatalytic processes in recent years. Leveraging plants as renewable resources reduces dependence on animal or microbial sources, providing significant potential for sustainable lipase production. These lipases are biodegradable and less toxic, enhancing their cost-effectiveness, particularly when sourced from plants with additional economic value. The diversity of plant species offers a wide array of lipases with different properties, broadening their industrial applications. Additionally, integrating plant lipase production into existing agricultural processes by using agricultural residues or by-products as enzyme sources can reduce costs and add value to waste materials. Despite their potential, several challenges must be addressed for the effective utilization of plant-derived lipases. Reducing extraction and purification costs is essential to make these enzymes competitive with other sources. Advancements in the biochemical and structural characterization of plant lipases have facilitated enzymatic engineering approaches to enhance enzyme stability, specificity, and catalytic efficiency. A review of the current research can help identify gaps and suggest new directions for enzyme development and technological advancements. Understanding the mechanisms of action and unique properties of plant lipases can drive innovations in biocatalytic processes. This review aims to highlight the characteristics of plant lipases and the challenges in their extraction, purification, and stability. This study conducted a narrative review using a database of relevant studies, selecting 92 studies. The future of plant lipases holds great promise for transformative impacts across various industries, promoting more sustainable and innovative practices.

Effect of the support alkyl chain nature in the functional properties of the immobilized lipases

Supports coated with amino-hexyl and amino octyl have been prepared from glyoxyl agarose beads and compared in their performance with octyl-agarose to immobilize lipases A and B from Candida antarctica (CALA and CALB). Immobilization courses were similar using all supports, but enzyme release was more difficult using the amino-alkyl supports suggesting a mixed interfacial activation/ionic exchange immobilization. The enzyme activity and specificity (using p-nitrophenyl propionate, triacetin and both isomers of methyl mandelate) greatly depended on the support. In many instances the enzymes immobilized on the new supports offered higher activities and enantiospecificity in the hydrolysis of both enantiomers of methyl mandelate (mainly using CALB). This was coupled to a lower enzyme stability using the new supports, even in the presence of high ionic strength, suggesting that the amphipathic could be responsible of the enzyme lower stability. Using CALB, it was possible to detect a higher exposition of the enzyme Trp groups to the medium by florescence spectra after its immobilization on the amino-alkyl-supports, correlating to the higher activity and lower stability results.

Tuning almond lipase features by the buffer used during immobilization: The apparent biocatalysts stability depends on the immobilization and inactivation buffers and the substrate utilized

The lipase from Prunus dulcis almonds was inactivated under different conditions. At pH 5 and 9, enzyme stability remained similar under the different studied buffers. However, when the inactivation was performed at pH 7, there were some clear differences on enzyme stability depending on the buffer used. The enzyme was more stable in Gly than when Tris was employed for inactivation. Then, the enzyme was immobilized on methacrylate beads coated with octadecyl groups at pH 7 in the presence of Gly, Tris, phosphate and HEPES. Its activity was assayed versus triacetin and S-methyl mandelate. The biocatalyst prepared in phosphate was more active versus S-methyl mandelate, while the other ones were more active versus triacetin. The immobilized enzyme stability at pH 7 depends on the buffer used for enzyme immobilization. The buffer used in the inactivation and the substrate used determined the activity. For example, glycine was the buffer that promoted the lowest or the highest stabilities depending on the substrate used to quantify the activities.

Molecular cloning, overexpression, characterization, and In silico modelling analysis of a novel GDSL autotransporter-dependent outer membrane lipase (OML) of Pseudomonas guariconensis

The outer membrane lipase (oml) gene, encoding a novel autotransporter-dependent lipase from Pseudomonas guariconensis, was cloned and sequenced. The oml gene has an open reading frame of 1866 bp. It encodes the 621 amino acid autotransporter-dependent GDSL lipase (OML), which has the highest sequence similarity (64.08 %) with the EstA of Pseudomonas aeruginosa (PDB:3kvn.1. A). OML was expressed and purified, which showed a purified band of approximately 70 kDa. The purified enzyme showed maximum activity at pH 9 and 40 °C. Substrate specificity studies and kinetic study by Lineweaver-Burk plot of purified OML showed Km of 1.27 mM and Vmax of 333.33 U/mL with p-nitrophenyl palmitate. The purified enzyme showed good stability in the presence of hexane, methanol, and ethanol, while the presence of the metal ion Mg2+ showed maximum lipase activity. Bioinformatics analysis supported the in vitro findings by predicting enzyme substrate specificity towards long-chain fatty acids and fatty acids with shorter chain lengths. The stability of the interaction of the protein-ligand complex (OML-ricinoleic acid) was confirmed using MDS and castor oil bioconversion using purified OML was confirmed using High-Performance Liquid Chromatography (HPLC).

Biocatalytic production of biolubricants: Strategies, problems and future trends

The increasing worries by the inadequate use of energy and the preservation of nature are promoting an increasing interest in the production of biolubricants. After discussing the necessity of producing biolubricants, this review focuses on the production of these interesting molecules through the use of lipases, discussing the different possibilities (esterification of free fatty acids, hydroesterification or transesterification of oils and fats, transesterification of biodiesel with more adequate alcohols, estolides production, modification of fatty acids). The utilization of discarded substrates has special interest due to the double positive ecological impact (e.g., oil distillated, overused oils). Pros and cons of all these possibilities, together with general considerations to optimize the different processes will be outlined. Some possibilities to overcome some of the problems detected in the production of these interesting compounds will be also discussed.

Immobilized lipase for sustainable hydrolysis of acidified oil to produce fatty acid

Acidified oil is obtained from by-product of crops oil refining industry, which is considered as a low-cost material for fatty acid production. Hydrolysis of acidified oil by lipase catalysis for producing fatty acid is a sustainable and efficient bioprocess that is an alternative of continuous countercurrent hydrolysis. In this study, lipase from Candida rugosa (CRL) was immobilized on magnetic Fe₃O₄@SiO₂ via covalent binding strategy for highly efficient hydrolysis of acidified soybean oil. FTIR, XRD, SEM and VSM were used to characterize the immobilized lipase (Fe₃O₄@SiO₂-CRL). The enzyme properties of the Fe₃O₄@SiO₂-CRL were determined. Fe₃O₄@SiO₂-CRL was used to catalyze the hydrolysis of acidified soybean oil to produce fatty acids. Catalytic reaction conditions were studied, including amount of catalyst, reaction time, and water/oil ratio. The results of optimization indicated that the hydrolysis rate reached 98% under 10 wt.% (oil) of catalyst, 3:1 (v/v) of water/oil ratio, and 313 K after 12 h. After 5 cycles, the hydrolysis activity of Fe₃O₄@SiO₂-CRL remained 55%. Preparation of fatty acids from high-acid-value by-products through biosystem shows great industrial potential.

Construction of a Novel Lipase Catalytic System Based on Hybrid Membranes with Interwoven Electrospun Polyacrylic Acid and Polyvinyl Pyrrolidone Gel Fibers

Efficient lipase catalysis requires sufficient oil-water interface engineered through structural design. Inspired by the architectural features of fabrics, a novel lipase-membrane catalytic system with interwoven polyacrylic acid (PAA) gel fibers and polyvinyl pyrrolidone (PVP) gel fibers was developed in this study by using double-needle electrospinning and gelation. It has been demonstrated that PAA/PVP hybrid gel fiber membranes (HGFMs) have a high swelling capacity for both water and oil phases, which created numerous discontinuous oil-water contact surface units in limited space of HGFMs, consequently forming effective interfacial catalytic systems. Volume competition between the water and oil phases suggests that balancing the proportions of these phases is very important for effective construction of oil-water interfaces and conditioning catalysis. Regulation of multiple factors of PAA/PVP HGFMs resulted in a catalytic efficiency of up to 2.1 times that of a macroscopic "oil-up/water-down" system (room temperature, pH = 7), and 2.9 times when three membranes are superimposed, as well as excellent pH and temperature stability. HGFMs were stacked to build a high-performing catalytic performance reactor. We expect that this study will be a beneficial exploration for expanding the lipase catalytic system.

Serratia sp. scl1: isolation of a novel thermostable lipase producing microorganism which holds industrial importance

Lipase being a hydrolysable enzyme plays a major role in serving various purposes of the industries. Thus, it is very important to have a sustainable and efficient source of this enzyme. In this present study, several microorganisms were isolated from medicinal effluent of a pharmaceutical industry that could produce efficient lipase activity. Among these isolates, a designated strain scl1 was isolated and based on the molecular and biochemical characterisation was tentatively assigned to the genus Serratia. Preliminary studies confirmed the strain scl1 was found to exhibit the highest production of lipase at a temperature and pH of 35 °C and 7, respectively under the incubation for 48 h. Further, the lipase activity was measured by following spectrophotometric method using pNPP as the substrate in which the Km and Vmax of the crude enzyme was found to be 3.349 × 10^-3 M and 5.68 × 10^-1 unit/mL, respectively. The extracellular crude lipase was found to show a temperature and pH optima of 75 °C and 8, respectively which gave a strong indication that the enzyme appeared to be highly thermostable. This study revealed the strain scl1 is able to produce a thermostable lipase which can meet the needs of the modern-day industrialization techniques. However, more work is required to purify the enzyme and get it ready for commercial applications.

Is enzyme immobilization a mature discipline? Some critical considerations to capitalize on the benefits of immobilization

Enzyme immobilization has been developing since the 1960s and although many industrial biocatalytic processes use the technology to improve enzyme performance, still today we are far from full exploitation of the field. One clear reason is that many evaluate immobilization based on only a few experiments that are not always well-designed. In contrast to many other reviews on the subject, here we highlight the pitfalls of using incorrectly designed immobilization protocols and explain why in many cases sub-optimal results are obtained. We also describe solutions to overcome these challenges and come to the conclusion that recent developments in material science, bioprocess engineering and protein science continue to open new opportunities for the future. In this way, enzyme immobilization, far from being a mature discipline, remains as a subject of high interest and where intense research is still necessary to take full advantage of the possibilities.

Progress in enrichment of n-3 polyunsaturated fatty acid: a review

n-3 Polyunsaturated fatty acids (n-3 PUFA) has been widely used in foods, and pharmaceutical products due to its beneficial effects. The content of n-3 PUFA in natural oils is usually low, which decreases its added value. Thus, there is an increasing demand on the market for n-3 PUFA concentrates. This review firstly introduces the differences in bioavailability and oxidative stability between different types of PUFA concentrate (free fatty acid, ethyl ester and acylglycerol), and then provides a comprehensive discussion of different methods for enrichment of lipids with n-3 PUFA including physical-chemical methods and enzymatic methods. Lipases used for catalyzing esterification, transesterification and hydrolysis reactions play an important role in the production of highly enriched various types of n-3 PUFA concentrates. Lipase-catalyzed alcoholysis or hydrolysis reactions are the mostly employed method to prepare high-quality n-3 PUFA of structural acylglycerols. Although many important advantages offered by lipases in enrichment of n-3 PUFA, the high cost of enzyme limits its industrial-scale production. Further research should focus on looking for biological enzymes with extraordinary catalytic ability and clear selectivity. Other novel technologies such as protein engineering and immobilization may be needed to modify lipases to improve its selectivity, catalytic ability and reuse.

Hydrolysis of Edible Oils by Fungal Lipases: An Effective Tool to Produce Bioactive Extracts with Antioxidant and Antimicrobial Potential

Hydrolysis of olive, rapeseed, linseed, almond, peanut, grape seed and menhaden oils was performed with commercial lipases of Aspergillus niger, Rhizopus oryzae, Rhizopus niveus, Rhizomucor miehei and Candida rugosa. In chromogenic plate tests, olive, rapeseed, peanut and linseed oils degraded well even after 2 h of incubation, and the R. miehei, A. niger and R. oryzae lipases exhibited the highest overall action against the oils. Gas chromatography analysis of vegetable oils hydrolyzed by R. miehei lipase revealed about 1.1 to 38.4-fold increases in the concentrations of palmitic, stearic, oleic, linoleic and α-linolenic acids after the treatment, depending on the fatty acids and the oil. The major polyunsaturated fatty acids produced by R. miehei lipase treatment from menhaden oil were linoleic, α-linolenic, hexadecanedioic, eicosapentaenoic, docosapentaenoic and docosahexaenoic acids, with yields from 12.02 to 52.85 µg/mL reaction mixture. Folin-Ciocalteu and ferric reducing power assays demonstrated improved antioxidant capacity for most tested oils after the lipase treatment in relation to the concentrations of some fatty acids. Some lipase-treated and untreated samples of oils, at 1.25 mg/mL lipid concentration, inhibited the growth of food-contaminating bacteria. The lipid mixtures obtained can be reliable sources of extractable fatty acids with health benefits.

Production of Jet Biofuels by Catalytic Hydroprocessing of Esters and Fatty Acids: A Review

The transition from fossil to bio-based fuels is a requisite for reducing CO2 emissions in the aviation sector. Jet biofuels are alternative aviation fuels with similar chemical composition and performance of fossil jet fuels. In this context, the Hydroprocessing of Esters and Fatty Acids (HEFA) presents the most consolidated pathway for producing jet biofuels. The process for converting esters and/or fatty acids into hydrocarbons may involve hydrodeoxygenation, hydrocracking and hydroisomerization, depending on the chemical composition of the selected feedstock and the desired fuel properties. Furthermore, the HEFA process is usually performed under high H2 pressures and temperatures, with reactions mediated by a heterogeneous catalyst. In this framework, supported noble metals have been preferably employed in the HEFA process; however, some efforts were reported to utilize non-noble metals, achieving a similar performance of noble metals. Besides the metallic site, the acidic site of the catalyst is crucial for product selectivity. Bifunctional catalysts have been employed for the complete process of jet biofuel production with standardized properties, with a special remark for using zeolites as support. The proper design of heterogeneous catalysts may also reduce the consumption of hydrogen. Finally, the potential of enzymes as catalysts for intermediate products of the HEFA pathway is highlighted.

Preparations from Campomanesia reitziana reduce the gastrointestinal motility and castor oil-induced diarrhea in a non-opioid and non-dopaminergic pathway in mice and display antimicrobial activity in vitro

BACKGROUND

This study investigated the antidiarrheal potential of the aqueous extract (AECR) and hydroalcoholic extract of Campomanesia reitziana leaves (HECR), its ethyl acetate (EAF) and dichloromethane fractions (DCMF), and myricitrin isolated from EAF.

METHODS

The total phenols and flavonoids were measured, followed by chromatography and myricitrin isolation. The 2,2-diphenyl-1-picryl-hydrazyl scavenger activity, the cytotoxicity, and the effects on LPS-induced nitrite production in intestinal epithelial cells (IEC-6) were quantified. The effect of HECR, EAF, DCMF, and AECR on intestinal motility (IT), gastric emptying (GE), and castor oil-induced diarrhea in mice was determined, as well as its antimicrobial activity.

KEY RESULTS

The administration of AECR 10% (10 ml/kg, p.o), but not HECR (300 mg/kg), reduced the GE and IT by 52 and 51%. The EAF and DCMF at 300 mg/kg also reduced IT but did not change GE. Moreover, AECR and EAF, but not DCMF, inhibited the castor oil-induced diarrhea and naloxone or metoclopramide pretreatment did not change these effects. Myricitrin did not change IT and the evacuation index of mice. Finally, the dry residue of AECR inhibited bacterial growth and EAF showed bacteriostatic activity against S. aureus, E. coli, and S. typhimurium and antifungal for C. albicans. However, none of the preparations alter the viability of Giardia spp. trophozoites.

CONCLUSIONS

The AECR and EAF can be effective to treat diarrhea acting through opioid- or dopaminergic type 2 receptor-independent mechanisms and by its antimicrobial actions.

An Electrospun Sandwich-Type Lipase-Membrane Bioreactor for Hydrolysis at Macroscopic Oil-Water Interfaces

The core task for lipase catalytic system design is to construct a suitable oil-water interface for lipase distribution. In comparison to the micro-oil-water interface, the macro-oil-water interface (top oil-bottom water) served as a simplified lipase catalytic system that is more in line with industrial applications but limited in catalytic efficiency. Based on the assumption that one potential carrier can help lipase reach to the macro-oil-water interface, in the current work, sandwich-type lipase-membrane bioreactors (SLMBs) fabricated by a facile layer-by-layer electrospinning process were reported. These SLMBs were composed of a hydrophilic polyamide 6 nanofibrous membrane (NFM) as the bottom layer, a blended electrospun lipase/PVA NFM as the middle layer, and a hydrophobic EC/PU NFM as the top layer. The lipase loading can be controlled by altering the electrospinning time of the middle layer. Under the optimized conditions, the catalytic efficiency of the SLMBs was 2.05 times higher than that of free lipase. In addition, the SLMBs exhibit much better pH (high activity over a broad pH range of 5-10), temperature (retained 62% at 80 °C), storage stability (no loss of activity after being stored at 4 °C for 11 days), and reusability (retained 23% after five cycles) than free lipase.

Preparation of Ricinoleic Acid from Castor Oil:A Review

Castor oil is a vegetable product extracted from Ricinus communis L (castor seed), which is primarily considered an important commercial value for the manufacturing of soaps, lubricants, coatings, etc. It is rich in hydroxylated fatty acids (ricinoleic acid, 89-92%) and is widely used in the cosmetic, pharmaceutical, oleochemical, and agricultural industries. This oil has also been confirmed as a bactericidal, anti-inflammatory, and antiherpetic agents, due to the ricinoleic acid having functional groups, such as -COOH, -OH, and -C=C-. Furthermore, it is converted into various acid derivative compounds with several applications. Therefore, this article reviewed some reaction stages to the preparation of ricinoleic acid from castor oil. Several methods or reaction pathways were employed in the preparation procedure, such as the Twitchell and Colgate-Emery processes, as well as the alkaline catalyzed, transesterification with methyl ricinoleic, and lipase-catalyzed hydrolysis, respectively. Although each of these preparation methods has advantages and disadvantages, the most effective technique was the hydrolysis through the use of the enzyme lipozyme TL IM. Besides being a green method, the conversion rate in the hydrolysis process was 96.2 ± 1.5.

Disrupting putative N-glycosylation site N17 in lipase Lip11 of Yarrowia lipolytica yielded a catalytically efficient and thermostable variant accompanying conformational changes

Lip11 gene from oleaginous yeast Yarrowia lipolytica MSR80 was recombinantly expressed in Pichia pastoris X33. Native secretion signal present in its sequence resulted in 92 % expression in comparison to α-secretion factor which resulted to 900 U/L in the extracellular broth. Catalytic triad in Lip11, like most lipases, was formed by serine, histidine, and aspartate residues. While point mutation disrupting putative glycosylation site (N389) present towards the C-terminus ruinously effected its stability and catalytic activity, disruption of the first putative glycosylation site (N17) located towards the N-terminus presented interesting insights. Mutation resulted in a variant N1 exhibiting higher thermal and acid stability; a t_1/2 of 198 min was obtained at 50 °C and it retained almost 80 % activity following incubation at pH 3. Catalytic efficiency was improved by 2.7 fold and a 10 °C rise in temperature optima was accompanied by higher relative activity in acidic range. Thermal stability corresponded to convoying structural modifications in the tertiary structure, findings of fluorescence spectroscopy suggested. Thermal fluorescence studies revealed a Tm of 65 °C for both Lip11 and N1 and λmax of Lip11 exhibited a blue shift upon refolding while no shift in the λmax of N1 was observed. A resilient tertiary structure which could fold back to its native confirmation upon thermal denaturation and increase in surface-exposed hydrophobic residues as revealed by ANS binding assay summed up to thermal stability of N1. Furthermore, circular dichroism data disclosed an alternate ratio of alpha-helices and beta-sheets; respective values changed from 36 % and 8%-27% and 19 %. Following mutation, substrate specificity remained unaffected and similar to native protein, N1 showed activation in presence of organic solvents and most divalent cations.

Direct and simultaneous analysis of lipase-catalyzed hydrolysis of high-oleic oil model by chiral stationary phase HPLC-ELSD

A novel HPLC-based method for direct separation of trioleoylglycerol (TOG), a major component in high-oleic oils, and its seven hydrolysis products (i.e., oleic acid, monooleoylglycerol (MOG) and dioleoylglycerol (DOG) isomers) was established using a chiral stationary phase column, Chiralpak IA. Within 20 min, all species including enantiomeric MOG (1-sn-MOG and 3-sn-MOG) and DOG (1,2-sn-DOG and 2,3-sn-DOG) were baseline-resolved with resolution factors over 1.5 between adjacent peaks. The established method was used for investigating the integral stereoselectivity, which is the selectivity concerning all hydrolysis steps, of lipase from Pseudomonas fluorescens (PFL) with TOG as substrate. The time-course of DOGs and MOGs indicated that PFL had selectivity for TOG hydrolysis in the order of sn-1, sn-2, and sn-3 position, while it preferred to hydrolyze 2,3-sn-DOG over 1,2-sn-DOG. Being rapid and accurate to evaluate integral stereoselectivity, this method could promote the development and application of lipases with target stereochemistry in the food industry.

Integral Stereoselectivity of Lipase Based on the Chromatographic Resolution of Enantiomeric/Regioisomeric Diacylglycerols

Stereoselectivity, a distinctive characteristic of lipase (EC 3.1.1.3), refers to the ability to differentiate between enantiomeric positions (sn-1 and sn-3) in triacylglycerol (TAG). This property has been determined based on the time course of enantiomeric excess of diacylglycerol (DAG) considering several consecutive steps of lipase-catalyzed hydrolysis of TAG; however, this concept is insufficient to represent the true nature of lipases which are capable of hydrolyzing the sn-2 position of TAG under the condition acyl migration occurs. Here, we suggest "integral stereoselectivity" to capture the preference of lipases for all ester groups of both TAG and DAG, as a novel index of the stereochemistry of lipase. To determine integral stereoselectivity, we established an analytical system based on the chromatographic resolution of dioleoylglycerol (DO) enantiomers and regioisomers. DO enantiomers were derivatized with 4-nitrophenyl isocyanate, and subsequently, resolved by chiral-phase high-performance liquid chromatography-ultraviolet. Regioisomers of monooleoylglycerol and DO were analyzed by HPLC with an evaporative light-scattering detector. Time-course analysis of three model lipases involved in the hydrolysis of trioleoylglycerol validated the analytical system designed to determine the integral stereoselectivity. As an accurate indicator of lipase stereochemistry reflecting all hydrolysis steps, integral stereoselectivity can expedite the development of lipases with unique stereochemistry from agricultural sources and their application to the food industry.

Ultrasound-assisted hydrolysis of lard for free fatty acids catalyzed by combined two lipases in aqueous medium

Lard is a by-product of animal processing. It is inexpensive compared with vegetable oils; however, its use is limited due to the high calorific value and high-saturated fatty acid content. While using lard as the source of free fatty acids (FFA) can significantly increase its utilization value. This study aimed to research the method on efficient hydrolysis of lard catalyzed by combi-lipases and assisted with ultrasound pretreatment. A 1,3-specific lipase from Rhizomucor miehei (termed pRML, 1540 U/mL) and a nonspecific mono- and diacylglycerol lipase from Penicillium cyclopium (termed MDL, 2000 U/mL) were used as biocatalysts. Results showed that the maximum hydrolysis rate of lard after 6 h at 45°C by using pRML and MDL alone was, respectively, 39.9% and 8.5%. When pRML combined with MDL (combi-lipases), hydrolysis rate can reach to 78.1%. While combi-lipases were assisted with 5 min ultrasound pretreatment before the reaction, the hydrolysis rate can further increase to 97%. The combi-lipases with different specificity and assisted with ultrasound pretreatment may be a useful technology for the enzyme production of FFA from complex lipid substrates, such as lard.

Enzymatic enrichment of n-3 polyunsaturated fatty acid glycerides by selective hydrolysis

Most natural oils are low in n-3 polyunsaturated fatty acids (n-3 PUFAs) content, which limits their application in health products. In this study, n-3 PUFAs in glyceride form were selectively enriched by lipase-mediated hydrolysis of n-3 PUFA-containing oils. First, commercial lipases were screened, and the lipase AY "Amano" 400SD from Candida cylindracea was the best choice in producing n-3 PUFA glycerides from tuna oil. Subsequently, the hydrolysis conditions were optimized. Under the optimal conditions, the highest n-3 PUFA content in the glyceride fraction was found to be 57.7% after enzymatic hydrolysis. Addition of Ca²⁺ to the system significantly shortened the reaction time from 10 to 4 h. When algal oil was used as substrate, total PUFA contents in the glyceride fraction were 89.9%. This study provides an efficient enzymatic process to produce n-3 PUFA-enriched glyceride concentrates and demonstrates that AY "Amano" 400SD can effectively discriminate against n-3 PUFAs during hydrolysis.

Status of the application of exogenous enzyme technology for the development of natural plant resources

Exogenous enzymes are extraneous enzymes that are not intrinsic to the subject. The exogenous enzyme industry has been rapidly developing recently. Successful application of recombinant DNA amplification, high-efficiency expression, and immobilization technology to genetically engineered bacteria provides a rich source of enzymes. Amylase, cellulase, protease, pectinase, glycosidase, tannase, and polyphenol oxidase are among the most widely used such enzymes. Currently, the application of exogenous enzyme technology in the development of natural plant resources mainly focuses on improving the taste and flavor of the product, enriching the active ingredient contents, deriving and transforming the structure of a chosen compound, and enhancing the biological activity and utilization of the functional ingredient. In this review, we discuss the application status of exogenous enzyme technology for the development of natural plant resources using typical natural active ingredients from plant, such as resveratrol, steviosides, catechins, mogrosides, and ginsenosides, as examples, to provide basis for further exploitation and utilization of exogenous enzyme technology.

Microbial lipase production: A deep insight into the recent advances of lipase production and purification techniques

Importance of enzymes is ever-rising particularly microbial lipases holding great industrial worth owing to their potential to catalyze a diverse array of chemical reactions in aqueous as well as nonaqueous settings. International lipase market is anticipated to cross USD 797.7 million till 2025, rising at a 6.2% compound annual growth rate from 2017 to 2025. The recent breakthrough in the field of lipase research is the generation of new and upgraded versions of lipases via molecular strategies. For example, integration of rational enzyme design and directed enzyme evolution to attain desired properties in lipases. Normally, purification of lipase with significant purity is achieved through a multistep procedure. Such multiple step approach of lipase purification entails both conventional and novel techniques. The present review attempts to provide an overview of different aspects of lipase production including fermentation techniques, factors affecting lipase production, and purification strategies, with the aim to assist researchers to pick a suitable technique for the production and purification of lipase.

Preparation of Lipase-Electrospun SiO2 Nanofiber Membrane Bioreactors and Their Targeted Catalytic Ability at the Macroscopic Oil-Water Interface

Lipase is one of the most widely used enzymes in biocatalysis. Because of the special structure of the catalytic active center, lipases show high catalytic activity at oil-water interfaces. Hence, the interface plays a key role in activating and modulating lipase biocatalysis. Compared with traditional catalytic systems that offer interfaces, such as emulsions, a lipase-membrane bioreactor exhibits many obvious advantages when at the macroscopic oil-water system. In our current research, a series of new Burkholderia cepacia lipase (BCL)-SiO₂ nanofiber membrane (NFM) bioreactors prepared via combined electrospinning and immobilization strategies were reported. These SiO₂ NFMs assisted BCL in reaching the oil-water interface for efficient catalysis. The enzyme loading capacity and catalytic efficiency of BCL-SiO₂ NFMs varied with the surface hydrophobicity of the electrospun NFMs. As the hydrophobicity increased, the activity decreased from 2.43-fold to 0.74-fold that of free BCL. However, the lipase-loading capacity increased obviously when the hydrophobicity of the SiO₂ NFMs increased from 0 to 143°, and no significant change was observed when the hydrophobicity of the SiO₂ NFMs increased from 143 to 153°. The gel trapping technique proved that the hydrolytic activity of the different BCL-SiO₂ NFM bioreactors depends on the contact area of the membrane at the oil-water interface. BCL-SiO₂ NFM, BCL-SiO₂ NFM-C₁₂, and BCL-SiO₂ NFM-C₁₈ retained 32, 83, and 42% of activity, respectively, after five cycles of reuse. The current work was a useful exploration of the construction and modification of lipase-membrane reactors based on electrospun inorganic silicon.

One Pot Use of Combilipases for Full Modification of Oils and Fats: Multifunctional and Heterogeneous Substrates

Lipases are among the most utilized enzymes in biocatalysis. In many instances, the main reason for their use is their high specificity or selectivity. However, when full modification of a multifunctional and heterogeneous substrate is pursued, enzyme selectivity and specificity become a problem. This is the case of hydrolysis of oils and fats to produce free fatty acids or their alcoholysis to produce biodiesel, which can be considered cascade reactions. In these cases, to the original heterogeneity of the substrate, the presence of intermediate products, such as diglycerides or monoglycerides, can be an additional drawback. Using these heterogeneous substrates, enzyme specificity can promote that some substrates (initial substrates or intermediate products) may not be recognized as such (in the worst case scenario they may be acting as inhibitors) by the enzyme, causing yields and reaction rates to drop. To solve this situation, a mixture of lipases with different specificity, selectivity and differently affected by the reaction conditions can offer much better results than the use of a single lipase exhibiting a very high initial activity or even the best global reaction course. This mixture of lipases from different sources has been called “combilipases” and is becoming increasingly popular. They include the use of liquid lipase formulations or immobilized lipases. In some instances, the lipases have been coimmobilized. Some discussion is offered regarding the problems that this coimmobilization may give rise to, and some strategies to solve some of these problems are proposed. The use of combilipases in the future may be extended to other processes and enzymes.

A Novel Fungal Lipase With Methanol Tolerance and Preference for Macaw Palm Oil

Macaw palm is a highly oil-producing plant, which presents high contents of free fatty acids, being a promising feedstock for biofuel production. The current chemical routes are costly and complex, involving highly harsh industrial conditions. Enzymatic processing is a potential alternative; however, it is hampered by the scarce knowledge on biocatalysts adapted to this acidic feedstock. This work describes a novel lipase isolated from the thermophilic fungus Rasamsonia emersonii (ReLip), which tolerates extreme conditions such as the presence of methanol, high temperatures, and acidic medium. Among the tested feedstocks, the enzyme showed the highest preference for macaw palm oil, producing a hydrolyzate with a final free fatty acid content of 92%. Crystallographic studies revealed a closed conformation of the helical amphipathic lid that typically undergoes conformational changes in a mechanism of interfacial activation. Such conformation of the lid is stabilized by a salt bridge, not observed in other structurally characterized homologs, which is likely involved in the tolerance to organic solvents. Moreover, the lack of conservation of the aromatic cluster IxxWxxxxxF in the lid of ReLip with the natural mutation of the phenylalanine by an alanine might be correlated with the preference of short acyl chains, although preserving catalytic activity on insoluble substrates. In addition, the presence of five acidic amino acids in the lid of ReLip, a rare property reported in other lipases, may have contributed to its ability to tolerate and be effective in acidic environments. Therefore, our work describes a new fungal biocatalyst capable of efficiently hydrolyzing macaw oil, an attractive feedstock for the production of "drop-in" biofuels, with high desirable feature for industrial conditions such as thermal and methanol tolerance, and optimum acidic pH. Moreover, the crystallographic structure was elucidated, providing a structural basis for the enzyme substrate preference and tolerance to organic solvents.

Novozym 435: the “perfect” lipase immobilized biocatalyst?

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

Combination of a protic ionic liquid-like surfactant and biocompatible solvents to generate environmentally friendly anionic reverse micelles

imim–DEHP, a versatile protic IL-like surfactant to formulate aqueous RMs in biocompatible non-polar solvents.

Catalytic characteristics of a sn-1(3) regioselective lipase from Cordyceps militaris

A total of 39 agricultural products were screened for natural sources of lipases with distinctive positional specificity. Based on this, Cordyceps militaris lipase (CML) was selected and subsequently purified by sequential chromatography involving anion-exchange, hydrophobic-interaction, and gel-permeation columns. As a result of the overall purification procedure, a remarkable increase in the specific activity of the CML (4.733 U/mg protein) was achieved, with a yield of 2.47% (purification fold of 94.54). The purified CML has a monomeric structure with a molecular mass of approximately 62 kDa. It was further identified as a putative extracellular lipase from C. militaris by the partial sequence analysis using ESI-Q-TOF MS. In a kinetic study of the CML-catalyzed hydrolysis, the values of V_max , K_m , and k_cat were determined to be 4.86 μmol·min^-1 ·mg^-1 , 0.07 mM, and 0.29 min^-1 , respectively. In particular, the relatively low K_m value indicated that CML has a high affinity for its substrate. With regard to positional specificity, CML selectively cleaved triolein at the sn-1 or 3 positions of glycerol backbone, releasing 1,2(2,3)-diolein as the major products. Therefore, CML can be considered a distinctive biocatalyst with sn-1(3) regioselectivity. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2744, 2019.

Enhanced Ricinoleic Acid Preparation Using Lipozyme TLIM as a Novel Biocatalyst: Optimized by Response Surface Methodology

Ricinoleic acid (RA) is an important raw material for plasticizers, emulsifiers, and nanomaterials. In this work, a green and efficient method was developed for RA production. Results showed that Lipozyme TLIM can be used as a novel biocatalyst to catalyze the hydrolysis of castor oil (CO) for RA preparation. Response surface methodology (RSM) was used to evaluate and optimize the effects of reaction variables on the hydrolysis of CO. Reaction conditions were optimized as follows: 41.3 °C, enzyme load 8.9%, 39.2 h, and 40:1 molar ratio of water to oil. Under these optimized reaction variables, the maximum hydrolysis ratio of CO (96.2 ± 1.5%) was obtained. The effect of hydrolysis variables on the reaction was as follows: enzyme load > hydrolysis time > temperature. In conclusion, this is a green, simple, and efficient method for RA preparation and can provide a good alternative method for RA industrial production.

Cloning and protein expression of the sn-1(3) regioselective lipase from Cordyceps militaris

In this study, the gene of a novel lipase with sn-1(3) regioselectivity (i.e., sn-1 or sn-3 specific) from Cordyceps militaris was successfully expressed by a heterologous expression system. Total RNA was extracted from C. militaris and then single-stranded cDNA was synthesized. The resulting C. militaris lipase (CML) gene was inserted in Escherichia coli expression plasmids [pET-29b(+), pET-26b, and pColdIII] to construct plasmids encoding CML, which were then transformed to E. coli strains BL21 (DE3), C43 (DE), C41 (DE3), and Origami (DE3) for protein expression. Although the recombinant CML expression level was high, it was overproduced in the form of inclusion bodies. Under a specific condition, the soluble form of the recombinant CML was detected using Western blot analysis; however, no enzyme activity was observed. To overcome the lack of post-translational modifications in recombinant CML, a baculovirus-insect expression system was introduced for eukaryotic lipase expression. pDualBac was used as the transfer vector, and the CML gene was fused under the control of the polyhedrin promoter. After generating the recombinant baculovirus, the active form of CML was successfully produced and its kinetic parameters were determined.

Lipase immobilization on high water adsorbing capacity bagasse: applications in bio-based plasticizer synthesis

This study investigates the structure and water adsorbing capacity of bagasse and of sodium hydroxide pretreated bagasse. The structures of bagasse and bagasse-NaOH were compared by SEM and XRD. Candida antarctica lipase B was then immobilized on bagasse, bagasse-NaOH and DPA@bagasse-NaOH. The expressed activity and immobilization yield of lipase immobilized on bagasse-NaOH (1.0%) was 36% and 45% higher than that on bagasse. When dopamine (DPA) was used as cationic polymer monomer via self-polymerization for mediating immobilization, the protein loading amounts and activity of lipase immobilized on DPA@bagasse-NaOH were higher than that of bagasse-NaOH. When the DPA concentration was 100 mg/ml, the immobilized lipase expressed activity reached its highest value (800 U/g), where the immobilization yield achieved 96.8%, which was 3.93-fold of lipase immobilized on native bagasse (24.6%). Then the immobilized lipases were used to synthesize a bio-based plasticizer. Lipase immobilized on DPA@bagasse-NaOH exhibited a significantly improved operational stability. Even after 12 batches, a high ester yield (84.2%) was maintained. Additionally, poly (vinyl chloride) PVC blends plasticized with methyl oleate as a secondary plasticizer were investigated. It was discovered that methyl oleate can be used as an effective bio-based plasticizer for PVC. These results indicate that bagasse with high water adsorbing capacity and self-polymerized DPA layer could create a favorable microenvironment for bio-based plasticizer synthesis in esterification reactions.

Free Radical Scavenging Capacity, Carotenoid Content, and NMR Characterization of Blighia sapida Aril Oil

Blighia sapida aril oil is rich in monounsaturated fatty acids but is however currently not utilized industrially. The oil was characterized utilizing nuclear magnetic resonance (NMR) and Fourier Transform Infrared Spectroscopy (FTIR). A spectrophotometric assay was conducted to determine the free radical scavenging properties and carotenoid content of the oil. Chemical shifts resonating between δ 5.30 and 5.32 in the ¹H NMR are indicative of olefinic protons present in ackee aril oil which are due to the presence of oleic acid. A peak at 3006 cm⁻¹ in the FTIR spectra confirms the high levels of monounsaturation. The oil has a free radical scavenging activity of 48%  ± 2.8% and carotenoid content of 21 ± 0.2 ppm.

A novel microbial technique for producing high-quality sophorolipids from horse oil suitable for cosmetic applications

Horse oil contains linoleic, palmitoleic and unsaturated fatty acids that are similar to those in human skin, and may therefore be an ideal substance from which to isolate biosurfactants for cosmetic products to improve human skin quality. Herein, an innovative approach was developed to synthesise sophorolipids from horse oil by hydrolysis, followed by fermentation using the yeast Candida bombicola. The yield of sophorolipids from direct fermentation of horse oil and hydrolysed horse oil was 40.6 ± 1.3 g l-1 and 58.4 ± 1.8 g l-1 respectively. To further increase the yield, 30-40 g l-1 glucose was added in a fed-batch fermentation process to maintain the pH between 4.0 and 4.5, resulting in a conversion yield of 71.7 ± 0.8 g l-1 . The purity and structure of the synthesised sophorolipids were analysed by ultra-performance liquid chromatography-mass spectrometry and nuclear magnetic resonance. An in vitro human dermal fibroblast model was used as a surrogate for human skin to measure elastase inhibition activity. Antiwrinkle properties of isolated sophorolipids were better than those of horse oil or hydrolysed horse oil in several in vitro assays. Furthermore, no cytotoxicity was observed at a concentration of 50 μg ml-1 , and wound-healing capacity was evident in a cell culture model. Additionally, the synthesised sophorolipids attenuated lipopolysaccharide-induced expression of inflammatory cytokines in macrophages, and efficiently inhibited several strains of bacteria and yeast. In conclusion, fed-batch fermentation of hydrolysed horse oil is a novel and efficient approach for producing high-quality and high-yield sophorolipids that exhibit great potential as cosmetic ingredients.

A novel and rapid method for fatty acid preparation by the lipase-catalyzed hydrolysis of Phoenix tree seeds

Fatty acids are the precursors for the production of fuels, oleochemicals and special health care products. In this study, a novel rapid method for fatty acid (FA) preparation by the enzymatic hydrolysis of Phoenix tree seed, an undeveloped woody oil seed, was developed. High-temperature GC with flame ionization detector (FID) and the hydrolysis ratio were used to monitor reaction progress. Enzyme screening and the effect of reaction variables on the hydrolysis of seeds were evaluated and optimized by response surface methodology. The results showed that among the tested enzymes, Lipozyme TLIM showed the greatest amount of hydrolysis of Phoenix tree seed. FAs can be rapidly prepared by one-step hydrolysis of Phoenix tree seeds using Lipozyme TLIM as the biocatalyst. Under the optimized conditions (6% enzyme load, 1:8 mass ratio of seed to water, 47.7 °C and 16 min), the maximum hydrolysis ratio (96.4 ± 1.1%) can be achieved. The effect of reaction variables on the hydrolysis decreased in the following order: reaction time > enzyme load > substrate ratio of seed to water > reaction temperature. This work provides a novel and rapid method for FA preparation from oil seeds.

Structural Characterization of Biocompatible Reverse Micelles Using Small-Angle X-ray Scattering, 31P Nuclear Magnetic Resonance, and Fluorescence Spectroscopy

The most critical problem regarding the use of reverse micelles (RMs) in several fields is the toxicity of their partial components. In this sense, many efforts have been made to characterize nontoxic RM formulations on the basis of biological amphiphiles and/or different oils. In this contribution, the microstructure of biocompatible mixed RMs formulated by sodium 1,4-bis-2-ethylhexylsulfosuccinate (AOT) and tri- n-octylphosphine oxide (TOPO) surfactants dispersed in the friendly solvent methyl laurate was studied by using SAXS and ³¹P NMR and by following the solvatochromic behavior of the molecular probe 4-aminophthalimide (4-AP). The results indicated the presence of RM aggregates upon TOPO incorporation with a droplet size reduction and an increase in the interfacial fluidity in comparison with pure AOT RMs. When confined inside the mixed systems, 4-AP showed a red-edge excitation shift and confirmed the increment of interfacial fluidity upon TOPO addition. Also, the partition between the external nonpolar solvent and the RM interface and an increase in both the local micropolarity and the capability to form a hydrogen bond interaction between 4-AP and a mixed interface were observed. The findings have been explained in terms of the nonionic surfactant structure and its complexing nature expressed at the interfacial level. Notably, we show how two different approaches, i.e., SAXS and the solvatochromism of the probe 4-AP, can be used in a complementary way to enhance our understanding of the interfacial fluidity of RMs, a parameter that is difficult to measure directly.

Micropolarity and Hydrogen-Bond Donor Ability of Environmentally Friendly Anionic Reverse Micelles Explored by UV/Vis Absorption of a Molecular Probe and FTIR Spectroscopy

In the present work we show how two biocompatible solvents, methyl laurate (ML) and isopropyl myristate (IPM), can be used as a less toxic alternative to replace the nonpolar component in a sodium 1,4-bis-2-ethylhexylsulfosuccinate (AOT) reverse micelles (RMs) formulation. In this sense, the micropolarity and the hydrogen-bond ability of the interface were monitored through the use of the solvatochromism of a molecular probe (1-methyl-8-oxyquinolinium betaine, QB) and Fourier transform infrared spectroscopy (FTIR). Our results demonstrate that the micropolarity sensed by QB in ML RMs is lower than in IPM RMs. Additionally, the water molecules form stronger H-bond interactions with the polar head of AOT in ML than in IPM. By FTIR was revealed that more water molecules interact with the interface in ML/AOT RMs. On the other hand, for AOT RMs generated in IPM, the weaker water-surfactant interaction allows the water molecules to establish hydrogen bonds with each other trending to bulk water more easily than in ML RMs, a consequence of the dissimilar penetration of nonpolar solvents into the interfacial region. The penetration process is strongly controlled by the polarity and viscosity of the external solvents. All of these results allow us to characterize these biocompatible systems, providing information about interfacial properties and how they can be altered by changing the external solvent. The ability of the nontoxic solvent to penetrate or not into the AOT interface produces a new interface with attractive properties.

Influence of the reaction conditions on the enzyme catalyzed transesterification of castor oil: A possible step in biodiesel production

The identification of the influence of the reaction parameters is of paramount importance when defining a process design. In this work, non-edible castor oil was reacted with methanol to produce a possible component for biodiesel blends, using liquid enzymes as the catalyst. Temperature, alcohol-to-oil molar ratio, enzyme and added water contents were the reaction parameters evaluated in the transesterification reactions. The optimal conditions, giving the optimal final FAME yield and FFA content in the methyl ester-phase was identified. At 35°C, 6.0 methanol-to-oil molar ratio, 5wt% of enzyme and 5wt% of water contents, 94% of FAME yield and 6.1% of FFA in the final composition were obtained. The investigation was completed with the analysis of the component profiles, showing that at least 8h are necessary to reach a satisfactory FAME yield together with a minor FFA content.

Enzymatic production of sterculic acid from the novel Phoenix tree seed oil: Optimization and kinetic study

Phoenix tree (Firmiana simplex) seed oil is a novel oil which is rich in sterculic acid. Sterculic acid, a cyclopropene fatty acid, can be used as the inhibitor of the stearoyl-CoA desaturase system and mammary carcinomas growth. In this work, Lipozyme TLIM-catalyzed hydrolysis of the novel Phoenix tree seed oil was used to prepare sterculic acid. High temperature GC-FID and the degree of hydrolysis (DH) were used to monitor the reaction progress. Effects of reaction variables on the hydrolysis were evaluated and optimized using response surface methodology. Results showed that sterculic acid can be successfully prepared from the novel seed oil, and the effect of reaction variables on the hydrolysis decreased in the order of reaction time > enzyme load > temperature. A high yield of fatty acids (DH, 98.2±0.8%) can be obtained under optimized conditions (45 ºC, mass ratio of water to oil 10:1, enzyme load 10%, and 18 h). The Arrhenius equation for the hydrolysis was LnV0 = 9.12-4721/T. The activation energy was 39.25KJ/mol. The kinetic values for Vmax, K/m were 0.232mol/(L∙min) and 0.084 mol/L, respectively.