Enzymatic esterification of free fatty acids in vegetable oils utilizing different immobilized lipases

Deacidification of high-acid rice bran oil by the tandem continuous-flow enzymatic reactors

Rice bran oil (RBO) contains a variety of nutrients, but the high acid values largely hinder its processing into edible oil. Thus, the tandem continuous-flow reactors are proposed and developed for the enzymatic deacidification of RBO and simultaneous production of functional oils. The results indicate that the Candida antarctica lipase B (CALB) immobilized on the hydrophobic ordered mesoporous silicon (OMS-C₁₈) increased 6.6 times of the catalytic activity and improved at least 20 ℃ of temperature tolerance compared to the commercial Novozym 435. The tandem continuous-flow enzymatic reactors removed 91.4% of free fatty acid and increased 9 and 12 times of phytosterol ester and diacylglycerol in RBO, respectively. Moreover, the retention rate of γ-oryzanol was at least 40% higher than that obtained by traditional alkali refining. This study provides an effective and sustainable method to continuously convert the low-value RBO into value-added products, which brings huge potential to cleaner industrial production.

Encapsulation of lipases by nucleotide/metal ion coordination polymers: enzymatic properties and their applications in glycerolysis and esterification studies

BACKGROUND

In the present study, lipases of TLL (lipase from Thermomyces lanuginosus), AOL (lipase from Aspergillus oryzae), RML (lipase from Rhizomucor miehei), BCL (lipase from Burkholderia cepacia), CALA (Candida antarctica lipase A) and LU (Lecitase® Ultra) were encapsulated into nucleotide-hybrid metal coordination polymers (CPs). Enzyme concentration was optimized for encapsulation and the enzymatic properties of the obtained lipases were investigated. In addition, their performance in glycerolysis and esterification was evaluated, and glycerolysis conditions (water content, temperature and time) were optimized.

RESULTS

Hydrolysis activity over 10 000 U g^-1 and activity recovery over 90% were observed from AOL@GMP/Tb, TLL@GMP/Tb and RML@GMP/Tb. GMP/Tb encapsulation (of AOL, TLL, RML and LU) improved their thermostability when incubated in air. The encapsulated lipases exhibited moderate [triacylglycerols (TAG) conversion 30-50%] and considerable glycerolysis activity (TAG conversion over 60%). TAG conversions from 69.37% to 82.35% and diacylglycerols (DAG) contents from 58.62% to 64.88% were obtained from CALA@GMP/metal samples (except for CALA@GMP/Cu). Interestingly, none of the encapsulated lipases initiated the esterification reaction. AOL@GMP/Tb, TLL@GMP/Tb, RML@GMP/Tb and CALA@GMP/Tb showed good reusability in glycerolysis, with 88.80%, 94.67%, 89.85% and 78.16% of their initial glycerolysis activity, respectively, remaining after five cycles of reuse. The relationships between temperature and TAG conversion were LnV₀  = 6.5364-3.7943/T and LnV₀  = 13.8820-6.4684/T for AOL@GMP/Tb and CALA@GMP/Tb, respectively; in addition, their activation energies were 31.55 and 53.78 kJ mol^-1 , respectively.

CONCLUSION

Most of the present encapsulated lipases exhibited moderate and considerable glycerolysis activity. In addition, AOL@GMP/Tb, TLL@GMP/Tb, RML@GMP/Tb and CALA@GMP/Tb exhibited good reusability in glycerolysis reactions and potential in practical applications. © 2022 Society of Chemical Industry.

Borage Oil Treated with Immobilized Lipase Inhibits Melanogenesis

In the present study, we demonstrated that borage (Borago officinalis L.) seed oil subjected to immobilized lipase pretreatment are enriched with linoleic acid (LNA, 18:2n-6), γ-linolenic acid (GLA, 18:3n-6), and oleic acid (OLA, 18:1n-9). We further showed that lipase-treated borage oil (LT-BOL) regulates the activity and degradation of tyrosinase, an important enzyme implicated in the synthesis of melanin in murine melanocytes, B16F10. LT-BOL and its free fatty acid components reduced the levels of melanin and tyrosinase in melanocytes with GLA exerting similar or stronger effects compared with LNA and OLA. The brightening efficacy of LT-BOL on melanin metabolism in humans was tested by an 8-week, double-blind, randomized clinical trial, which enrolled 21 Korean female adults (mean age 48.57 ± 3.28). Visual evaluation showed that cream containing 1% LT-BOL significantly decreased (p < 0.05) melasma on the treated skin area after 6 and 8 weeks. The analysis of the skin brightness using Chromameter CR-400 confirmed that the brightness of the treated area was significantly increased (p < 0.01) after 4, 6, and 8 weeks. Together, our results suggest that LT-BOL may be suitable as a natural skin whitening cosmeceutical product.

Effects of enzymatic free fatty acid reduction process on the composition and phytochemicals of rice bran oil

The effects of enzymatic free fatty acid reduction process (EFFARP) on the composition and phytochemicals of dewaxed and degummed rice bran oil (DDRBO) were investigated and compared with the effects observed using internal acyl acceptors. The acid value of DDRBO was effectively decreased from 16.99 mg KOH/g to approximately 0.36 mg KOH/g by EFFARP. EFFARP significantly decreased the moisture content and peroxide value of DDRBO and increased the induction period. The Sn-2 fatty acid comoposition of DDRBO after EFFARP was very reaching the total fatty acid composition. EFFARP significantly increased the triacylglycerol content compared to the control, while the oryzanol content was not obviously affected. The contents of free sterol, and total tocopherol and tocotrienol were increased slightly by EFFARP compared to the control. When conducted under vacuum with added nitrogen, EFFARP shows great application potential in the edible oil industry.

Immobilization of Aspergillus niger lipase onto a novel macroporous acrylic resin: Stable and recyclable biocatalysis for deacidification of high-acid soy sauce residue oil

Deacidification of high-acid soy sauce residue (SSR) oil is crucial to utilization of SSR oil. Aspergillus niger lipase (ANL) has been widely applied for such purpose while its immobilization still has large room for improvement. ANL was immobilized onto six different macroporous acrylic resins, accounting the effect of the different textural properties of resins on stability and their potential for application in enzymatic deacidification. The resin MARE with lower porosity, higher bulk density, and medium hydrophobicity, was chosen as the best carrier for the best thermostability and reusability. ANL-MARE is a promising catalyst than Novozym 40086, which not only exhibited higher deacidification activity and good thermostability, but also was continuously reused for 15 cycles and efficiently catalyzed from high-acid SSR oil into diacylglycerol-enriched oil. Therefore, immobilized ANL was a novel, low-cost and recyclable biocatalyst that could be used as a good alternative to higher-cost commercial lipases in industrial applications.

Novel Combi-lipase Systems for Fatty Acid Ethyl Esters Production

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.

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.