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1.
Nature ; 603(7901): 488-492, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35102311

RESUMO

The SARS-CoV-2 Omicron variant (B.1.1.529) has multiple spike protein mutations1,2 that contribute to viral escape from antibody neutralization3-6 and reduce vaccine protection from infection7,8. The extent to which other components of the adaptive response such as T cells may still target Omicron and contribute to protection from severe outcomes is unknown. Here we assessed the ability of T cells to react to Omicron spike protein in participants who were vaccinated with Ad26.CoV2.S or BNT162b2, or unvaccinated convalescent COVID-19 patients (n = 70). Between 70% and 80% of the CD4+ and CD8+ T cell response to spike was maintained across study groups. Moreover, the magnitude of Omicron cross-reactive T cells was similar for Beta (B.1.351) and Delta (B.1.617.2) variants, despite Omicron harbouring considerably more mutations. In patients who were hospitalized with Omicron infections (n = 19), there were comparable T cell responses to ancestral spike, nucleocapsid and membrane proteins to those in patients hospitalized in previous waves dominated by the ancestral, Beta or Delta variants (n = 49). Thus, despite extensive mutations and reduced susceptibility to neutralizing antibodies of Omicron, the majority of T cell responses induced by vaccination or infection cross-recognize the variant. It remains to be determined whether well-preserved T cell immunity to Omicron contributes to protection from severe COVID-19 and is linked to early clinical observations from South Africa and elsewhere9-12.


Assuntos
COVID-19/imunologia , COVID-19/virologia , Reações Cruzadas/imunologia , Imunidade Celular , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Linfócitos T/imunologia , Adulto , Idoso , Vacinas contra COVID-19/imunologia , Convalescença , Hospitalização , Humanos , Pessoa de Meia-Idade , SARS-CoV-2/química , SARS-CoV-2/classificação
2.
Nature ; 603(7902): 679-686, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35042229

RESUMO

The SARS-CoV-2 epidemic in southern Africa has been characterized by three distinct waves. The first was associated with a mix of SARS-CoV-2 lineages, while the second and third waves were driven by the Beta (B.1.351) and Delta (B.1.617.2) variants, respectively1-3. In November 2021, genomic surveillance teams in South Africa and Botswana detected a new SARS-CoV-2 variant associated with a rapid resurgence of infections in Gauteng province, South Africa. Within three days of the first genome being uploaded, it was designated a variant of concern (Omicron, B.1.1.529) by the World Health Organization and, within three weeks, had been identified in 87 countries. The Omicron variant is exceptional for carrying over 30 mutations in the spike glycoprotein, which are predicted to influence antibody neutralization and spike function4. Here we describe the genomic profile and early transmission dynamics of Omicron, highlighting the rapid spread in regions with high levels of population immunity.


Assuntos
COVID-19/epidemiologia , COVID-19/virologia , Evasão da Resposta Imune , SARS-CoV-2/isolamento & purificação , Anticorpos Neutralizantes/imunologia , Botsuana/epidemiologia , COVID-19/imunologia , COVID-19/transmissão , Humanos , Modelos Moleculares , Mutação , Filogenia , Recombinação Genética , SARS-CoV-2/classificação , SARS-CoV-2/imunologia , África do Sul/epidemiologia , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/imunologia
3.
Biotechnol Lett ; 46(1): 85-95, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38064041

RESUMO

The objective of this study was to obtain sufficient information on the thermal stabilization of a food-grade lipase from Thermomyces lanuginosus (TLL) using the immobilization technique. To do this, a new non-porous support was prepared via the sequential extraction of SiO2 from rice husks, followed by functionalization with (3-aminopropyl) triethoxysilane - 3-APTES (Amino-SiO2), and activation with glutaraldehyde - GA (GA-Amino-SiO2). We evaluated the influence of GA concentration, which varied from 0.25% v v-1 to 4% v v-1, on the immobilization parameters and enzyme thermal stabilization. The thermal inactivation parameters for both biocatalyst forms (soluble or immobilized TLL) were calculated by fitting a non-first-order enzyme inactivation kinetic model to the experimental data. According to the results, TLL was fully immobilized on the external support surface activated with different GA concentrations using an initial protein load of 5 mg g-1. A sharp decrease of hydrolytic activity was observed from 216.6 ± 12.4 U g-1 to 28.6 ± 0.9 U g-1 of after increasing the GA concentration from 0.25% v v-1 to 4.0% v v-1. The support that was prepared using a GA concentration at 0.5% v v-1 provided the highest stabilization of TLL - 31.6-times more stable than its soluble form at 60 °C. The estimations of the thermodynamic parameters, e.g., inactivation energy (Ed), enthalpy (ΔH#), entropy (ΔS#), and the Gibbs energy (ΔG#) values, confirmed the enzyme stabilization on the external support surface at temperatures ranging from 50 to 65 °C. These results show promising applications for this new heterogeneous biocatalyst in industrial processes given the high catalytic activity and thermal stability.


Assuntos
Lipase , Oryza , Propilaminas , Silanos , Lipase/metabolismo , Dióxido de Silício , Glutaral , Enzimas Imobilizadas/metabolismo , Termodinâmica , Estabilidade Enzimática
4.
Bioprocess Biosyst Eng ; 47(3): 313-323, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38438572

RESUMO

Molecular docking is an important computational analysis widely used to predict the interaction of enzymes with several starting materials for developing new valuable products from several starting materials, including oils and fats. In the present study, molecular docking was used as an efficient in silico screening tool to select biocatalysts with the highest catalytic performance in butyl esters production in a solvent-free system, an eco-friendly approach, via direct esterification of free fatty acids from Licuri oil with butanol. For such purpose, three commercial lipase preparations were used to perform molecular docking studies such as Burkholderia cepacia (BCL), Porcine pancreatic (PPL), and Candida rugosa (CRL). Concurrently, the results obtained in BCL and CRL are the most efficient in the esterification process due to their higher preference for catalyzing the esterification of lauric acid, the main fatty acid found in the licuri oil composition. Meanwhile, PPL was the least efficient because it preferentially interacts with minor fatty acids. Molecular docking with the experimental results indicated the better performance in the synthesis of esters was BCL. In conclusion, experimental results analysis shows higher enzymatic productivity in esterification reactions of 1294.83 µmol/h.mg, while the CRL and PPL demonstrated the lowest performance (189.87 µmol / h.mg and 23.96 µmol / h.mg, respectively). Thus, molecular docking and experimental results indicate that BCL is a more efficient lipase to produce fatty acids and esters from licuri oil with a high content of lauric acid. In addition, this study also demonstrates the application of molecular docking as an important tool for lipase screening to achieve more sustainable production of butyl esters with a view synthesis of biolubricants.


Assuntos
Ácidos Graxos , Lipase , Animais , Suínos , Lipase/química , Simulação de Acoplamento Molecular , Domínio Catalítico , Ácidos Graxos/química , Esterificação , Ésteres , Ácidos Láuricos , Enzimas Imobilizadas/metabolismo
6.
Biotechnol Appl Biochem ; 70(3): 1291-1301, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36576317

RESUMO

The present study consists of developing an enzymatic process for the production of wax esters (lauryl stearate and cetyl stearate) by esterification in a heptane medium. Lipase from Thermomyces lanuginosus (TLL) immobilized via interfacial activation on silica particles from rice husks functionalized with triethoxy(octyl)silane (TLL-Octyl-SiO2 ) was used as biocatalyst. Maximum immobilized protein loading of around 22 mg g-1 (that corresponds to an immobilization yield of ≈55%) of support was observed using an initial protein loading of 40 mg g-1 of Octyl-SiO2 . Its hydrolytic activity (olive oil emulsion hydrolysis) was of 620 U g-1 of biocatalyst. The effect of certain factors on the cetyl estearate production was evaluated using a central composite rotatable design (CCDR). Under optimal conditions (64°C, 21% of mass of biocatalyst per volume of reaction mixture, 170 rpm, and stoichiometric acid:alcohol molar ratio 1 mol L-1 of each reactant), maximum acid conversion percentage of 91% was observed after 60 min of reaction. Lauryl stearate was also produced under such conditions, and an acid conversion of 93% after 60 min of reaction was also achieved. Free lipase exhibited acid conversion of only 15%-20% for both reaction mixtures. After nine successive esterification batches, TLL-Octyl-SiO2 retained 85%-90% of its original activity. These results show the promising use of the prepared biocatalyst in wax esters production due to its high catalytic activity and reusability.


Assuntos
Lipase , Oryza , Lipase/metabolismo , Esterificação , Ésteres , Dióxido de Silício , Adsorção , Estearatos , Enzimas Imobilizadas/metabolismo , Biocatálise
7.
Zygote ; 31(6): 582-587, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37955189

RESUMO

Traditionally, in vitro oocyte and embryo culture progresses through a series of varying culture medium. To investigate simplifying the in vitro production of bovine cumulus-oocyte complexes (COCs), this study used synthetic oviductal fluid (SOF) supplemented with conjugated linoleic acid (CLA). Special interest was placed on gene expression linked to lipid metabolism and oocyte maturation. COCs were matured in different media: Medium 199 (M199 group), M199 with 100 µM CLA (M199 + CLA group), SOF (SOF group), and SOF with 100 µM CLA (SOF + CLA group). COCs matured with SOF showed a higher relative abundance of mRNA of quality indicators gremlin 1 (GREM1) and prostaglandin-endoperoxide synthase 2 (PTGS2) in oocytes, and GREM1 in cumulus cells compared with in the M199 group. SOF medium COCs had a higher relative abundance of fatty acid desaturase 2 (FADS2) compared with the M199 group, which is essential for lipid metabolism in oocytes. Furthermore, the abundance of stearoyl-coenzyme A desaturase 1 (SCD1) in oocytes matured with SOF was not influenced by the addition of CLA, whereas the relative abundance of SCD1 was reduced in M199 medium with CLA. We concluded that maturation in SOF medium results in a greater abundance of genes linked to quality and lipidic metabolism in oocytes, regardless of the addition of CLA.


Assuntos
Fertilização in vitro , Metabolismo dos Lipídeos , Feminino , Animais , Bovinos , Metabolismo dos Lipídeos/genética , Oócitos/metabolismo , Oogênese , Meios de Cultura/farmacologia , Meios de Cultura/metabolismo , Expressão Gênica , Técnicas de Maturação in Vitro de Oócitos/métodos
8.
Bioprocess Biosyst Eng ; 46(1): 53-67, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36409316

RESUMO

The enzymatic production of isoamyl levulinate via esterification of isoamyl alcohol (IA) and levulinic acid (LA), a biomass-based platform chemical with attractive properties, in a solvent system has been performed in this study. For such a purpose, a low-cost liquid lipase (Eversa® Transform 2.0) immobilized by physical adsorption via hydrophobic interactions (mechanism of interfacial activation) on mesoporous poly(styrenene-divinylbenzene) (PSty-DVB) beads was used as heterogeneous biocatalyst. It was prepared at low ionic strength (5 mmol.L-1 buffer sodium acetate pH 5.0) and 25 â„ƒ using an initial protein loading of 40 mg.g-1 of support. Maximum protein loading of 31.2 ± 2.8 mg.g-1 of support and an immobilization yield of 83% was achieved. The influence of relevant factors (biocatalyst concentration and reaction temperature) on ester production was investigated using a central composite rotatable design (CCRD). Maximum acid conversion percentage of 65% was achieved after 12 h of reaction at 40 °C, 20% of mass of heterogeneous biocatalyst per mass of reaction mixture (20% m.m-1), and LA:IA molar ratio of 1:1.5 in a methyl isobutyl ketone (MIBK) medium. The biocatalyst retained around of 30% of its initial activity after five consecutive esterification batches under optimal experimental conditions. The proposed experimental procedure can be considered as an acceptable green process (EcoScale score of 66.5), in addition to the fact that a new strategy is proposed to sustainably produce a valuable industrial ester (isoamyl levulinate) from biomass-based materials using an immobilized and low-cost commercial lipase as catalyst.


Assuntos
Enzimas Imobilizadas , Ésteres , Enzimas Imobilizadas/química , Biomassa , Esterificação , Lipase/química
9.
Eur J Orthop Surg Traumatol ; 33(3): 571-580, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36094673

RESUMO

INTRODUCTION: The standard treatment of anterior glenaoid fractures carrying > 20% of the glenoid fossa is open reduction and internal fixation (ORIF). In the herein study, we report our outcomes in a retrospective cohort of anterior and anteroinferior glenoid rim fractures using an accelerated postoperative rehabilitation protocol. A secondary aim is to describe the surgical steps for ORIF of anterior and anteroinferior glenoid rim fractures using the anterior axillary approach, describing the tricks, pearls, and pitfalls of this surgical technique. METHODS: A retrospective cohort of skeletally mature patients treated for an anterior glenoid rim fracture carrying > 20% of the glenoid fossa during a 10-year period were operated on using a vertical axillary incision, osteosynthesis with 2.0-mm cortical screws, and labral repair with small diameter metallic anchors and non-absorbable sutures. Rehabilitation began on the first postoperative day, including passive external rotation exercises and active-assisted flexion, adduction, and abduction exercises as tolerated. The exercises are performed with the patient sitting or lying down. Phase 1 is continued for 6-10 weeks until the patient regains painless, normal, or near-normal ROM. Usually by 10 weeks, the fracture and labrum are healed, so phase 2 rehabilitation begins with strengthening and ROM exercises. Radiologic and clinical outcomes, including active range of motion (ROM), glenohumeral stability, and visual analogue scale (VAS) were measured. RESULTS: About 33 patients (35 fractures) had complete medical records and pre- and post-operative imaging exams available for further analysis regarding the surgical protocol, with a mean of 4.8 years. The mean DASH questionnaire was 3.75 ± 9.0 and the mean CM score was 62.5 ± 0.1. Active flexion and internal rotation were recovered in all patients, while external rotation presented an average loss of 8° (p = 0.12) and abduction of 5° (p = 0.33). The mean VAS was 1.1 ± 0.8. No patient reported major or disabling symptoms, or great difficulty or inability to perform daily or recreational activities. No patient presented residual instability of the glenohumeral joint. CONCLUSION: In this retrospective cohort, ORIF using a vertical axillary incision, osteosynthesis with 2.0-mm screws, and labral repair with small diameter metallic anchors and non-absorbable sutures was a safe approach, with a minimal risk of complications and residual instability. The accelerated postoperative rehabilitation protocol, allowing immediate passive external rotation of the operated shoulder, resulted in a non-significant loss of ROM compared to the contralateral side. Therefore, we recommend this management strategy for anterior glenoid rim fractures in patients with unstable shoulder joint after traumatic glenohumeral dislocation. LEVEL OF EVIDENCE IV: Therapeutic Study (Surgical technique and Retrospective cohort).


Assuntos
Fraturas Ósseas , Instabilidade Articular , Luxação do Ombro , Articulação do Ombro , Humanos , Estudos Retrospectivos , Escápula/cirurgia , Fraturas Ósseas/cirurgia , Fraturas Ósseas/complicações , Fixação Interna de Fraturas/efeitos adversos , Fixação Interna de Fraturas/métodos , Articulação do Ombro/cirurgia , Luxação do Ombro/cirurgia , Instabilidade Articular/etiologia , Amplitude de Movimento Articular , Artroscopia/métodos , Resultado do Tratamento
10.
Biotechnol Lett ; 44(1): 89-99, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34738223

RESUMO

OBJECTIVES: To immobilize Candida rugosa lipase in Accurel MP 1000 (CRL-AMP) by physical adsorption in organic medium and apply in the synthesis of wax esters dodecanoyl octadecanoate 1 and hexadecanoyl octadecanoate 2 in a heptane medium, as well as evaluating the stability and recyclability of CRL-AMP in six reaction cycles. RESULTS: The specific activity (Asp) for CRL-AMP was 200 ± 20 U mg-1. Its catalytic activity was 1300 ± 100 U g-1. CRL-AMP was used in the synthesis of esters in heptane medium with a 1:1 acid:alcohol molar ratio at 45 °C and 200 rpm. In synthesis 1, conversion was 62.5 ± 3.9% in 30 min at 10% m v-1 and 56.9 ± 2.8% in 54 min at 5% m v-1; while in synthesis 2, conversion was 79.0 ± 3.9% in 24 min at 10% m v-1, and 46.0 ± 2.4% in 54 min at 5% m v-1. Reuse tests after six consecutive cycles of reaction showed that the biocatalyst retained approximately 50% of its original activity for both reaction systems. CONCLUSIONS: CRL-AMP showed a high potential in the production of wax esters, since it started from low enzymatic load and high specific activities and conversions were obtained, in addition to allowing an increase in stability and recyclability of the prepared biocatalyst.


Assuntos
Ésteres , Lipase , Biocatálise , Candida/metabolismo , Emolientes , Estabilidade Enzimática , Enzimas Imobilizadas/metabolismo , Esterificação , Lipase/metabolismo , Saccharomycetales
11.
World J Microbiol Biotechnol ; 39(1): 25, 2022 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-36422728

RESUMO

In recent years, fluctuating global fossil fuel market prices and growing concern about environmental pollution have increased efforts to obtain novel value-added products from renewable agricultural biomass. To this end, a wide variety of triacylglycerols (edible and non-edible oils and fats) and their derivatives (free fatty acids or monoalkyl esters) stand out as promising feedstocks for the production of biolubricant base stocks, due to their biodegradability, excellent physicochemical properties, and sustainable nature. These raw materials can be transformed into biolubricants using chemical or biochemical (lipases) catalysts, with the enzymatic production of biolubricants using lipases as catalysts being recognized as an environmentally friendly approach. The present mini-review highlights recent advances in this field, published in the last three years. The different chemical modification processes used to develop a wide variety of industrial biolubricant base stocks are comprehensively reviewed, with exploration of future prospects for industrial production via the enzymatic route. This study contributes to the current state-of-the-art, identifying relevant research questions and providing important technical information for new applications of lipases in oleochemical manufacturing industries.


Assuntos
Ésteres , Lipase , Triglicerídeos , Óleos de Plantas , Indústrias
12.
BMC Infect Dis ; 21(1): 539, 2021 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-34098893

RESUMO

BACKGROUND: In sub-Saharan Africa, acute respiratory infections (ARI), acute gastrointestinal infections (GI) and acute febrile disease of unknown cause (AFDUC) have a large disease burden, especially among children, while respective aetiologies often remain unresolved. The need for robust infectious disease surveillance to detect emerging pathogens along with common human pathogens has been highlighted by the ongoing novel coronavirus disease 2019 (COVID-19) pandemic. The African Network for Improved Diagnostics, Epidemiology and Management of Common Infectious Agents (ANDEMIA) is a sentinel surveillance study on the aetiology and clinical characteristics of ARI, GI and AFDUC in sub-Saharan Africa. METHODS: ANDEMIA includes 12 urban and rural health care facilities in four African countries (Côte d'Ivoire, Burkina Faso, Democratic Republic of the Congo and Republic of South Africa). It was piloted in 2018 in Côte d'Ivoire and the initial phase will run from 2019 to 2021. Case definitions for ARI, GI and AFDUC were established, as well as syndrome-specific sampling algorithms including the collection of blood, naso- and oropharyngeal swabs and stool. Samples are tested using comprehensive diagnostic protocols, ranging from classic bacteriology and antimicrobial resistance screening to multiplex real-time polymerase chain reaction (PCR) systems and High Throughput Sequencing. In March 2020, PCR testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and analysis of full genomic information was included in the study. Standardised questionnaires collect relevant clinical, demographic, socio-economic and behavioural data for epidemiologic analyses. Controls are enrolled over a 12-month period for a nested case-control study. Data will be assessed descriptively and aetiologies will be evaluated using a latent class analysis among cases. Among cases and controls, an integrated analytic approach using logistic regression and Bayesian estimation will be employed to improve the assessment of aetiology and associated risk factors. DISCUSSION: ANDEMIA aims to expand our understanding of ARI, GI and AFDUC aetiologies in sub-Saharan Africa using a comprehensive laboratory diagnostics strategy. It will foster early detection of emerging threats and continued monitoring of important common pathogens. The network collaboration will be strengthened and site diagnostic capacities will be reinforced to improve quality management and patient care.


Assuntos
Doenças Transmissíveis/diagnóstico , Doenças Transmissíveis/epidemiologia , Programas de Rastreamento , Vigilância de Evento Sentinela , Teorema de Bayes , Burkina Faso , Estudos de Casos e Controles , Côte d'Ivoire , República Democrática do Congo , Febre/epidemiologia , Febre/microbiologia , Gastroenteropatias/epidemiologia , Gastroenteropatias/microbiologia , Humanos , Reação em Cadeia da Polimerase em Tempo Real , Infecções Respiratórias/epidemiologia , África do Sul
13.
Biotechnol Appl Biochem ; 68(3): 538-546, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32438471

RESUMO

The present study aimed at preparing three biocatalysts via physical adsorption of lipases from Candida rugosa (CRL), Mucor javanicus, and Candida sp. on a hydrophobic and mesoporous support (Diaion HP-20). These biocatalysts were later applied to the synthesis of aromatic esters of apple peel and citrus (hexyl butyrate), apple and rose (geranyl butyrate), and apricot and pineapple (propyl butyrate). Scanning electron microscopy and gel electrophoresis confirmed a selective adsorption of lipases on Diaion, thus endorsing simultaneous immobilization and purification. Gibbs free energy (∆G) evinced the spontaneity of the process (-17.9 kJ/mol ≤ ∆G ≤ -5.1 kJ/mol). Maximum immobilized protein concentration of 30 mg/g support by CRL. This biocatalyst was the most active in olive oil hydrolysis (hydrolytic activity of 126.0 ± 2.0 U/g) and in the synthesis of aromatic esters. Maximum conversion yield of 89.1% was attained after 150 Min for the synthesis of hexyl butyrate, followed by the synthesis of geranyl butyrate (87.3% after 240 Min) and propyl butyrate (80.0% after 150 Min). CRL immobilized on Diaion retained around 93% of its original activity after six consecutive cycles of 150 Min for the synthesis of hexyl butyrate.


Assuntos
Enzimas Imobilizadas/metabolismo , Ésteres/metabolismo , Hidrocarbonetos Aromáticos/metabolismo , Lipase/metabolismo , Mucor/enzimologia , Saccharomycetales/enzimologia , Enzimas Imobilizadas/química , Ésteres/química , Hidrocarbonetos Aromáticos/química , Interações Hidrofóbicas e Hidrofílicas , Lipase/química , Tamanho da Partícula , Propriedades de Superfície
14.
Biotechnol Appl Biochem ; 66(5): 823-832, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31206795

RESUMO

Alternative strategies are required to develop the optimized production of fatty acids using biocatalysis; molecular docking and response surface methodology are efficient tools to achieve this goal. In the present study, we demonstrate a novel and robust methodology for the sustainable production of fatty acids from Moringa oleifera Lam oil using lipase-catalyzed hydrolysis (without the presence of emulsifiers or buffer solutions). Seven commercial lipases from Candida rugosa (CRL), Burkholderia cepacia (BCL), Thermomyces lanuginosus (TLL), Rhizopus niveus (RNL), Pseudomonas fluorescens (PFL), Mucor javanicus (MJL), and porcine pancreas (PPL) were used as biocatalysts. Initial screening showed that CRL had the highest hydrolytic activity (hydrolysis degree of 81%). Molecular docking analysis contributed to the experimental results, showing that CRL displays more stable binding free energy with oleic acid (C18:1), which is the fatty acid of highest concentration in Moringa oleifera Lam oil. To evaluate and optimize the hydrolysis process, response surface methodology (RSM) was used. The effect of temperature, mass ratio oil:water, and hydrolytic activity on enzymatic hydrolysis was evaluated by central composite design using RSM. Under the optimized conditions (temperature of 37 °C, mass ratio oil:water of 25%, and hydrolytic activity of 550 U goil -1 ), the maximum hydrolysis degree (100%) was achieved. The present study provides a robust method for the enzymatic hydrolysis of different oils for efficient and sustainable fatty acid production.


Assuntos
Ácidos Graxos/análise , Lipase/metabolismo , Simulação de Acoplamento Molecular , Moringa oleifera/metabolismo , Óleos de Plantas/metabolismo , Biocatálise , Hidrólise , Moringa oleifera/química , Óleos de Plantas/química
15.
Bioprocess Biosyst Eng ; 42(10): 1647-1659, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31218406

RESUMO

This study aimed to optimize free fatty acid production by enzymatic hydrolysis of cottonseed, olive and palm kernel oils in stirred-tank reactors using a lipase from Geotrichum candidum (GCL-I). The effect of pH, temperature and substrate concentration on the hydrolytic activity of GCL-I using these vegetable oils was investigated. Thermal stability tests and thermodynamic studies were also performed. A complete hydrolysis of cottonseed oil was obtained after 120 min of reaction, while for olive and palm kernel maximum hydrolysis percentage was 96.4% and 60.1%, respectively. GCL-I exhibited the highest activity in the hydrolysis of vegetable oils that are rich in unsaturated-fatty acids (cottonseed and olive oils). Under optimal conditions (46.8% m/m of oil, 6.6 U/g of the reaction mixture at 40 °C), complete cottonseed oil hydrolysis was observed at 60 min of reaction performed in an emulsifier-free system with no buffer.


Assuntos
Ácidos Graxos/química , Proteínas Fúngicas/química , Geotrichum/enzimologia , Lipase/química , Óleo de Palmeira/química , Hidrólise
16.
Bioprocess Biosyst Eng ; 41(7): 991-1002, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29574490

RESUMO

Commercial lipase from Thermomyces lanuginosus has been immobilized on glutaraldehyde-activated rice husk particles via covalent attachment. It was reached maximum immobilized protein concentration of 27.5 ± 1.8 mg g-1 of dry support using the initial protein loading of 40 mg g-1 of support. The immobilized biocatalyst was used to synthesize cetyl oleate (wax ester) via direct esterification of oleic acid and cetyl alcohol. The influence of relevant factors on ester synthesis, such as reaction temperature, biocatalyst concentration, presence or lack of hydrophobic organic solvents, acid:alcohol molar ratio, and reaction time has been evaluated. The experimental data were well fitted to a second-order reversible kinetic model to determine apparent kinetic constants. Thermodynamic studies have revealed that the reaction was a spontaneous and endothermic process. Under optimal experimental conditions, it was observed maximum ester conversion of 90.2 ± 0.6% in 9 h of reaction time in hexane medium using 1 M of each reactant (cetyl alcohol and oleic acid), at 50 °C and biocatalyst concentration of 15% m/v of reaction mixture. Similar conversion (91.5 ± 0.8%) in a solvent-free system was also obtained within 24 h of reaction. The biocatalyst retained 85% of its initial activity after 12 cycles within 9 h of reaction in hexane medium. The physicochemical properties of purified ester have been determined in accordance with ASTM standards. The results indicate that the prepared biocatalyst has great potential for wax ester synthesis due to its satisfactory catalytic activity and operational stability.


Assuntos
Ascomicetos/enzimologia , Enzimas Imobilizadas/química , Proteínas Fúngicas/química , Lipase/química , Oryza/química , Ceras , Catálise , Esterificação , Álcoois Graxos/química , Glutaral/química , Ácido Oleico/química , Ceras/síntese química , Ceras/química
17.
Molecules ; 23(4)2018 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-29584655

RESUMO

Short-chain alkyl esters and sugar esters are widely used in the food, pharmaceutical and cosmetic industries due to their flavor and emulsifying characteristics, respectively. Both compounds can be synthesized via biocatalysis using lipases. This work aims to compare the performance of commercial lipases covalently attached to dry acrylic beads functionalized with oxirane groups (lipases from Candida antarctica type B-IMMCALB-T2-350, Pseudomonas fluorescens-IMMAPF-T2-150, and Thermomyces lanuginosus-IMMTLL-T2-150) and a home-made biocatalyst (lipase from Pseudomonas fluorescens adsorbed onto silica coated with octyl groups, named PFL-octyl-silica) in the syntheses of short- and long-chain carboxylic acid esters. Esters with flavor properties were synthetized by esterification of acetic and butyl acids with several alcohols (e.g., ethanol, 1-butanol, 1-hexanol, and isoamyl alcohol), and sugar esters were synthetized by esterification of oleic and lauric acids with fructose and lactose. All biocatalysts showed similar performance in the syntheses of short-chain alkyl esters, with conversions ranging from 88.9 to 98.4%. However, in the syntheses of sugar esters the performance of PFL-octyl-silica was almost always lower than the commercial IMMCALB-T2-350, whose conversion was up to 96% in the synthesis of fructose oleate. Both biocatalysts showed high operational stability in organic media, thus having great potential for biotransformations.


Assuntos
Ácidos Carboxílicos/síntese química , Enzimas Imobilizadas/metabolismo , Lipase/metabolismo , Biocatálise , Candida/enzimologia , Ácidos Carboxílicos/química , Estabilidade Enzimática , Esterificação , Pseudomonas fluorescens/enzimologia
18.
Undersea Hyperb Med ; 45(2): 209-215, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29734573

RESUMO

INTRODUCTION: CrossFit is a physical fitness program characterized by high-intensity workouts that can be associated with serious injury. Acute compartment syndrome in the upper limbs is a rare occurrence. It may occur after intense physical exercise, and its usual treatment is surgical. Hyperbaric oxygen therapy is a treatment described as adjunctive in cases of compartmental syndrome. PRESENTATION: We describe the case of a CrossFit practitioner who, after intense training, developed progressive symptoms of rhabdomyolysis and acute bilateral arm compartment syndrome, who was successfully treated with hyperbaric oxygen therapy and required no fasciotomy as surgical treatment. CONCLUSIONS: Acute compartment syndrome in the arms after intense physical exercise is a rare occurrence that should be suspected by practitioners of physical activity experiencing intense, disproportionate and progressive pain. In the case presented, hyperbaric oxygen therapy was successfully used in the treatment of the disorder, with satisfactory progress, and without the need for a surgical fasciotomy as therapy.


Assuntos
Braço , Síndromes Compartimentais/terapia , Treinamento Intervalado de Alta Intensidade/efeitos adversos , Oxigenoterapia Hiperbárica/métodos , Doença Aguda , Adulto , Braço/diagnóstico por imagem , Síndromes Compartimentais/diagnóstico por imagem , Síndromes Compartimentais/etiologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Amplitude de Movimento Articular , Rabdomiólise/etiologia , Rabdomiólise/terapia , Rabdomiólise/urina
19.
Molecules ; 22(2)2017 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-28146090

RESUMO

Lipases from Thermomyces lanuginosus (TLL) and Pseudomonas fluorescens (PFL) wereimmobilized on functionalized silica particles aiming their use in the synthesis of fructose oleate in a tert-butyl alcohol/water system. Silica particles were chemically modified with octyl (OS), octyl plus glutaraldehyde (OSGlu), octyl plus glyoxyl(OSGlx), and octyl plus epoxy groups(OSEpx). PFL was hyperactivated on all functionalized supports (more than 100% recovered activity) using low protein loading (1 mg/g), however, for TLL, this phenomenon was observed only using octyl-silica (OS). All prepared biocatalysts exhibited high stability by incubating in tert-butyl alcohol (half-lives around 50 h at 65 °C). The biocatalysts prepared using OS and OSGlu as supports showed excellent performance in the synthesis of fructose oleate. High estersynthesis was observed when a small amount of water (1%, v/v) was added to the organic phase, allowing an ester productivity until five times (0.88-0.96 g/L.h) higher than in the absence of water (0.18-0.34 g/L.h) under fixed enzyme concentration (0.51 IU/g of solvent). Maximum ester productivity (16.1-18.1 g/L.h) was achieved for 30 min of reaction catalyzed by immobilized lipases on OS and OSGlu at 8.4 IU/mL of solvent. Operational stability tests showed satisfactory stability after four consecutive cycles of reaction.


Assuntos
Enzimas Imobilizadas , Frutose/química , Lipase/metabolismo , Ácido Oleico/síntese química , Dióxido de Silício , Biocatálise , Estabilidade Enzimática , Lipase/química , Modelos Moleculares , Conformação Molecular , Solventes , Água
20.
Prep Biochem Biotechnol ; 47(1): 100-109, 2017 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-27136358

RESUMO

The present study reports the improved enzymatic synthesis of ethyl valerate (green apple flavor) by esterification reaction of ethanol and valeric acid in heptane medium. Lipase from Thermomyces lanuginosus (TLL) was immobilized by physical adsorption on polyhydroxybutyrate (PHB) particles and used as a potential biocatalyst. The effect of certain parameters that influence the ester synthesis was evaluated by factorial design. The experimental conditions that maximized the synthesis of ethyl valerate were 30.5°C, 18% m/v of biocatalyst (TLL-PHB), absence of molecular sieves, agitation of 234 rpm, and 1,000 mM of each reactant (ethanol and valeric acid). Under these conditions, conversion percentage ≈92% after 105 min of reaction was observed. Soluble TLL was also used as biocatalyst and the highest conversion was of 82% after 120 min of reaction. Esterification reaction performed in a solvent-free system exhibited conversion of 13% after 45 min of reaction catalyzed by immobilized lipase, while the soluble lipase did not exhibit catalytic activity. The synthesis of the ester was confirmed by Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry analyses. After six consecutive cycles of ethyl valerate synthesis, the prepared biocatalyst retained ≈86% of its original activity.


Assuntos
Enzimas Imobilizadas/metabolismo , Lipase/metabolismo , Solventes/química , Valeratos/metabolismo , Ascomicetos/enzimologia , Esterificação
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