In vitro Evaluation of the Antileishmanial and Antischistosomal Activities of p-Coumaric Acid Prenylated Derivatives.

We have evaluated eight p-coumaric acid prenylated derivatives in vitro for their antileishmanial activity against Leishmania amazonensis promastigotes and their antischistosomal activity against Schistosoma mansoni adult worms. Compound 7 ((E)-3,4-diprenyl-4-isoprenyloxycinnamic alcohol) was the most active against L. amazonensis (IC50=45.92 µM) and S. mansoni (IC50=64.25 µM). Data indicated that the number of prenyl groups, the presence of hydroxyl at C9, and a single bond between C7 and C8 are important structural features for the antileishmanial activity of p-coumaric acid prenylated derivatives.

Improving propionic acid production from a hemicellulosic hydrolysate of sorghum bagasse by means of cell immobilization and sequential batch operation.

Propionic acid (PA) is an important organic compound with extensive application in different industrial sectors and is currently produced by petrochemical processes. The production of PA by large-scale fermentation processes presents a bottleneck, particularly due to low volumetric productivity. In this context, the present work aimed to produce PA by a biochemical route from a hemicellulosic hydrolysate of sorghum bagasse using the strain Propionibacterium acidipropionici CIP 53164. Conditions were optimized to increase volumetric productivity and process efficiency. Initially, in simple batch fermentation, a final concentration of PA of 17.5 g⋅L-1 was obtained. Next, fed batch operation with free cells was adopted to minimize substrate inhibition. Although a higher concentration of PA was achieved (38.0 g⋅L-1 ), the response variables (YP/S = 0.409 g⋅g-1 and QP = 0.198 g⋅L-1 ⋅H-1 ) were close to those of the simple batch experiment. Finally, the fermentability of the hemicellulosic hydrolysate was investigated in a sequential batch with immobilized cells. The PA concentration achieved a maximum of 35.3 g⋅L-1 in the third cycle; moreover, the volumetric productivity was almost sixfold higher (1.17 g⋅L-1 ⋅H-1 ) in sequential batch than in simple batch fermentation. The results are highly promising, providing preliminary data for studies on scaling up the production of this organic acid.

Development of amphotericin B-loaded propionate Sterculia striata polysaccharide nanocarrier.

This work was aimed at the production and characterization of a new nanocarrier based on a Sterculia striata polysaccharide (SSP) modified via acylation reaction with propionic anhydride. Nanocapsules of propionated SSP (PSSP) were produced via spontaneous nanoemulsification process and tested as a potential amphotericin B (AMB) nanocarrier. Stable nanoparticles with a very low polydispersity index (0.08-0.29) and high zeta potential (ζ -42.7 to -53.8 mV) were obtained. Particle size was dependent on the degree of substitution and ranged from 205 to 286 nm. A nanocapsule with a degree of substitution (DS) of 2.53 (NCP 2.53) was selected for encapsulation, biocompatibility, and antifungal evaluation against Candida albicans strains. A maximum of 98.3% AMB encapsulation was achieved. Encapsulated AMB was in its monomeric form and showed good biocompatibility and antifungal activity against four C. albicans strains. Data indicate that PSSP has potential as a nanocarrier system for AMB.

Trypanocidal Mechanism of Action and in silico Studies of p-Coumaric Acid Derivatives.

Trypanosoma species are responsible for chronic and systemic infections in millions of people around the world, compromising life quality, and family and government budgets. This group of diseases is classified as neglected and causes thousands of deaths each year. In the present study, the trypanocidal effect of a set of 12 ester derivatives of the p-coumaric acid was tested. Of the test derivatives, pentyl p-coumarate (7) (5.16 ± 1.28 µM; 61.63 ± 28.59 µM) presented the best respective trypanocidal activities against both epimastigote and trypomastigote forms. Flow cytometry analysis revealed an increase in the percentage of 7-AAD labeled cells, an increase in reactive oxygen species, and a loss of mitochondrial membrane potential; indicating cell death by necrosis. This mechanism was confirmed by scanning electron microscopy, noting the loss of cellular integrity. Molecular docking data indicated that of the chemical compounds tested, compound 7 potentially acts through two mechanisms of action, whether by links with aldo-keto reductases (AKR) or by comprising cruzain (CZ) which is one of the key Trypanosoma cruzi development enzymes. The results indicate that for both enzymes, van der Waals interactions between ligand and receptors favor binding and hydrophobic interactions with the phenolic and aliphatic parts of the ligand. The study demonstrates that p-coumarate derivatives are promising molecules for developing new prototypes with antiprotozoal activity.

N-alkylimidazolium Salts Functionalized with p-Coumaric and Cinnamic Acid: A Study of Their Antimicrobial and Antibiofilm Effects.

The bacterial resistance to antibiotics has compromised the therapies used for bacterial infections. Nowadays, many strategies are being carried out to address this problem. Among them, the use of natural compounds like cinnamic and p-coumaric acids stands out. Nevertheless, their utilization is limited because of their unfavorable physicochemical properties. Due to the lack of new therapeutic alternatives for bacterial infections, novel strategies have emerged, such as the use of ionic liquids; given that they can show a broad spectrum of antibacterial activity, this is why we herein report the antibacterial and antibiofilm activity of a series of N-alkylimidazolium salts functionalized with p-coumaric and cinnamic acids. The results from this study showed better antibacterial activity against Gram-positive bacteria, with a predominance of the salts derived from coumaric acid and a correlation with the chain length. Additionally, a lower efficacy was observed in the inhibition of biofilm formation, highlighting the antibiofilm activity against Staphylococcus aureus, which decreased the production of the biofilm by 52% over the control. In conclusion, we suggest that the salts derived from p-coumaric acid are good alternatives as antibacterial compounds. Meanwhile, the salt derived from cinnamic acid could be a good alternative as an antibiofilm compound.

Effect of addition of adjuvants on physical and chemical characteristics of Bt bioinsecticide mixture.

Bacillus thuringiensis (Bt) is the main bacterium used in the formulation of bioinsecticides because it produces toxins and spores that are toxic to several orders of insects. The efficacy of Bt bioinsecticide is influenced by the quality of its application. The association with other crop protection products, such as adjuvants, can affect the physical and chemical parameters of the mixture. This study evaluated the physical and chemical parameters, volume median diameter (VMD), uniformity coefficient of droplets (SPAN), percentage of volume in drift droplets (%V <100 µm), contact angle, surface tension, potential of hydrogen (pH) and electrical conductivity (E.C.) of Bt bioinsecticides in concentrated suspension (SC), and wettable powder (WP) formulations associated with adjuvants. The largest droplet diameter and smallest values of drift droplets were found in the WP formulation with lower drift potential. The addition of mineral oil and surfactant to the mixtures of bioinsecticide reduced contact angle values and surface tension of the droplets, resulting in greater spreading of droplets in leaves. The addition of lecithin and propionic-acid-based adjuvants lowered the pH in both formulations. The adjuvants used in this study affected the physical and chemical characteristics of the mixtures, improving or impairing the quality of Bt bioinsecticide applications.

In Silico Evaluation of Ibuprofen and Two Benzoylpropionic Acid Derivatives with Potential Anti-Inflammatory Activity.

Inflammation is a complex reaction involving cellular and molecular components and an unspecific response to a specific aggression. The use of scientific and technological innovations as a research tool combining multidisciplinary knowledge in informatics, biotechnology, chemistry and biology are essential for optimizing time and reducing costs in the drug design. Thus, the integration of these in silico techniques makes it possible to search for new anti-inflammatory drugs with better pharmacokinetic and toxicological profiles compared to commercially used drugs. This in silico study evaluated the anti-inflammatory potential of two benzoylpropionic acid derivatives (MBPA and DHBPA) using molecular docking and their thermodynamic profiles by molecular dynamics, in addition to predicting oral bioavailability, bioactivity and toxicity. In accordance to our predictions the derivatives proposed here had the potential capacity for COX-2 inhibition in the human and mice enzyme, due to containing similar interactions with the control compound (ibuprofen). Ibuprofen showed toxic predictions of hepatotoxicity (in human, mouse and rat; toxicophoric group 2-arylacetic or 3-arylpropionic acid) and irritation of the gastrointestinal tract (in human, mouse and rat; toxicophoric group alpha-substituted propionic acid or ester) confirming the literature data, as well as the efficiency of the DEREK 10.0.2 program. Moreover, the proposed compounds are predicted to have a good oral bioavailability profile and low toxicity (LD50 < 700 mg/kg) and safety when compared to the commercial compound. Therefore, future studies are necessary to confirm the anti-inflammatory potential of these compounds.

Molecular interactions between p-coumaric acid and snake venom toxins.

A large number of natural compounds, such as phenolic compounds, have been scientifically evaluated in the search for enzyme inhibitors. The interactions between the phenolic compound p-coumaric acid and the enzymes present in snake venoms (used as research tools) were evaluated in vitro and in silico. The p-coumaric acid was able to inhibit 31% of the phospholipase activity induced by Bothrops alternatus venom, 27% of the hemolytic activity induced by B. moojeni, 62.5% of the thrombolytic activity induced by B. jararacussu, and approximately 27% of the activity thrombosis induced by Crotalus durissus terrificus. Previous incubation of p-coumaric acid with the venoms of B. atrox and B. jararacussu increased the coagulation time by 2.18 and 2.16-fold, respectively. The activity of serine proteases in B. atrox and B. jararacussu venoms was reduced by 60% and 66.34%, respectively. Computational chemistry analyses suggests the specific binding of p-coumaric acid to the active site of proteases through hydrogen and hydrophobic interactions. The phenolic compound evaluated in this work has great potential in therapeutic use to both prevent and treat hemostatic alterations, because the venom proteins inhibited by the p-coumaric acid have high homology with human proteins that have a fundamental role in several pathologies.

A Review of Analytical Methods for p-Coumaric Acid in Plant-Based Products, Beverages, and Biological Matrices.

p-Coumaric acid (p-CA), also known as 4-hydroxycinnamic acid, is a phenolic acid, which has been widely studied due to its beneficial effects against several diseases and its wide distribution in the plant kingdom. This phenolic compound can be found in the free form or conjugated with other molecules; therefore, its bioavailability and the pathways via which it is metabolized change according to its chemical structure. p-CA has potential pharmacological effects because it has high free radical scavenging, anti-inflammatory, antineoplastic, and antimicrobial activities, among other biological properties. It is therefore essential to choose the most appropriate and effective analytical method for qualitative and quantitative determination of p-CA in different matrices, such as plasma, urine, plant extracts, and drug delivery systems. The most-reported analytical method for this purpose is high-performance liquid chromatography, which is mostly coupled with some type of detectors, such as UV/Vis detector. However, other analytical techniques are also used to evaluate this compound. This review presents a summary of p-CA in terms of its chemical and pharmacokinetic properties, pharmacological effects, drug delivery systems, and the analytical methods described in the literature that are suitable for its quantification.

Secochiliolide ester derivatives: Preparation and evaluation of their antitrypanosomal and antimalarial efficacy.

In the present study, a series of new esters of secochiliolide acid (SA), a diterpene isolated from Nardophyllum bryoides, were synthesized in good yield. All compounds were evaluated for their in vitro antiparasitic properties (on Plasmodium falciparum and Trypanosoma brucei brucei) and cytotoxicity (on WI38, normal mammalian cells). They displayed moderate antitrypanosomal activity with IC50 values between 2.55 and 18.14 µm, with selectivity indices >10, and low antiplasmodial effects with IC50  > 29 µm. The only exception was the n-hexyl ester of SA, which showed a strong and selective antiplasmodial activity (IC50  = 1.99 µm and selectivity index = 117.0). The in vivo antimalarial efficacy of this compound was then assessed according to the 4-day suppressive test of Peters in mice. An intraperitoneal treatment at 50 mg kg-1  day-1 induced a slight parasitaemia reduction by 56% which was statistically significant on day 4 post-infection and an increase in the survival time.

Synthesis, molecular docking and biological evaluation of novel phthaloyl derivatives of 3-amino-3-aryl propionic acids as inhibitors of Trypanosoma cruzi trans-sialidase.

In the last two decades, trans-sialidase of Trypanosoma cruzi (TcTS) has been an important pharmacological target for developing new anti-Chagas agents. In a continuous effort to discover new potential TcTS inhibitors, 3-amino-3-arylpropionic acid derivatives (series A) and novel phthaloyl derivatives (series B, C and D) were synthesized and molecular docking, TcTS enzyme inhibition and determination of trypanocidal activity were carried out. From four series obtained, compound D-11 had the highest binding affinity value (-11.1 kcal/mol) compared to reference DANA (-7.8 kcal/mol), a natural ligand for TS enzyme. Furthermore, the 3D and 2D interactions analysis of compound D-11 showed a hydrogen bond, π-π stacking, π-anion, hydrophobic and Van der Waals forces with all important amino acid residues (Arg35, Arg245, Arg314, Tyr119, Trp312, Tyr342, Glu230 and Asp59) on the active site of TcTS. Additionally, D-11 showed the highest TcTS enzyme inhibition (86.9% ±â€¯5) by high-performance ion exchange chromatography (HPAEC). Finally, D-11 showed better trypanocidal activity than the reference drugs nifurtimox and benznidazole with an equal % lysis (63 ±â€¯4 and 65 ±â€¯2 at 10 µg/mL) and LC50 value (52.70 ±â€¯2.70 µM and 46.19 ±â€¯2.36 µM) on NINOA and INC-5 strains, respectively. Therefore, D-11 is a small-molecule with potent TcTS inhibition and a strong trypanocidal effect that could help in the development of new anti-Chagas agents.

Computational Study of the Binding Modes of Diverse DPN Analogues on Estrogen Receptors (ER) and the Biological Evaluation of a New Potential Antiestrogenic Ligand.

Estrogen (17ß-estradiol) is essential for normal growth and differentiation in the mammary gland. In the last three decades, previous investigations have revealed that Estrogen Receptor Alpha (ERα) plays a critical role in breast cancer. More recently, observations regarding the widespread expression of ERß-like proteins in normal and neoplastic mammary tissues have suggested that ERß is also involved in the mentioned pathology. Design of new drugs both steroidal and nonsteroidal that target any of these receptors represents a promise to treat breast cancer although it remains a challenge due to the sequence similarity between their catalytic domains. In this work, we propose a new set of compounds that could effectively target the estrogen receptors ERα and ERß. These ligands were designed based on the chemical structure of the ERß-selective agonist Diarylpropionitrile (DPN). The designed ligands were submitted to in silico ADMET studies, yielding in a filtered list of ligands that showed better drug-like properties. Molecular dynamics simulations of both estrogen receptors and docking analysis were carried-out employing the designed compounds, from which two were chosen due to their promising characteristics retrieved from theoretical results (docking analysis or targeting receptor predictions). They were chemically synthetized and during the process, two precursor ligands were also obtained. These four ligands were subjected to biological studies from which it could be detected that compound mol60b dislplayed inhibitory activity and its ability to activate the transcription via an estrogenic mechanism of action was also determined. Interestinly, this observation can be related to theoretical binding free energy calculations, where the complex: ERß-mol60b showed the highest energy ΔGbind value in comparison to others.

Chemical composition, fermentation profile and apparent digestibility of sugarcane silage treated with chemical additives / Composição química, perfil fermentativo e digestabilidade aparente de silagens de cana-de-açúcar tratadas com aditivos químicos

The aim of this study was the indication of an additive for the ensilage of sugarcane (Saccharum officinarum L.). In a laboratory trial, nine treatments were applied (g of additive/kg of fresh forage - FF) to the sugarcane (RB867515), before ensiling in minisilos (15 x 30 cm PVC tubes) during 78 days: untreated; urea (5) + sodium benzoate (0.5); urea (7.5) + benzoate (0.5); urea (5) + benzoate (0.75); urea (7.5) + benzoate (0.75); sodium propionate (1, 2 and 4); calcium hydroxide (10). Urea + benzoate in the lowest doses, propionate in the higher concentration and calcium hydroxide were selected, considering the ethanol content (26.5, 27.2 and 7.4 g/kg DM, respectively), total DM loss (88, 46 and 58 g/kg DM, respectively) and digestibility (541, 496 and 516 g/kg DM, respectively) of the silages. Silages treated with these doses of additives and the untreated silage (80 d of storage) were fed (nine + seven d) to 16 castrated male sheep (Santa Inês) housed in metabolic cages. The silage with calcium hydroxide presented coefficients of apparent digestibility of DM (0.44), of NDF (0.4) and DM intake (20 g/kg live weight) in the higher levels. Calcium hydroxide was superior to propionate and urea + benzoate, considering alcoholic fermentation control and reduction of losses in the silage and the forages nutritional value.(AU)

O objetivo deste estudo foi indicar um aditivo para a ensilagem da cana-de-açúcar (Saccharum officinarum L.). Em um ensaio de laboratório, nove tratamentos foram aplicados (g de aditivo/kgde forragem fresca - FF) à cana-de-açúcar (RB867515) antes da ensilagem em minisilos (tubos de PVC de 15 x 30 cm) durante 78 d: sem tratamento; uréia (5) + benzoato de sódio (0,5); uréia (7,5) + benzoato (0,5); uréia (5) + benzoato (0,75); uréia (7,5) + benzoato (0,75); propionato de sódio (1, 2 e 4); hidróxido de cálcio (10). Uréia + benzoato nas doses mais baixas, propionato na dose mais alta e hidróxido de cálcio foram selecionados, considerando a concentração de etanol (26,5; 27,2 e 7,4 g/kgMS, respectivamente), perda total de MS (88, 46 e 58 g/kg MS, respectivamente) e digestibilidade (541, 496 e 516 g/kg MS, respectivamente) das silagens. Silagens tratadas com estas dosagens dos aditivos e silagem não tratada (80 d estocagem) foram fornecidas (nove + sete d) a 16 carneiros (Santa Inês) machos castrados mantidos em gaiolas metabólicas. A silagem com hidróxido de cálcio apresentou coeficientes de digestibilidade aparente da MS (0,44), da FDN (0,40) e de ingestão da MS (20 g/kg peso vivo) nos níveis mais altos. Hidróxido de cálcio foi superior ao propionato e à uréia + benzoato, considerando-se o controle da fermentação alcoólica, a redução de perdas e o valor nutritivo da silagem.(AU)

Chemical composition, fermentation profile and apparent digestibility of sugarcane silage treated with chemical additives / Composição química, perfil fermentativo e digestabilidade aparente de silagens de cana-de-açúcar tratadas com aditivos químicos

The aim of this study was the indication of an additive for the ensilage of sugarcane (Saccharum officinarum L.). In a laboratory trial, nine treatments were applied (g of additive/kg of fresh forage - FF) to the sugarcane (RB867515), before ensiling in minisilos (15 x 30 cm PVC tubes) during 78 days: untreated; urea (5) + sodium benzoate (0.5); urea (7.5) + benzoate (0.5); urea (5) + benzoate (0.75); urea (7.5) + benzoate (0.75); sodium propionate (1, 2 and 4); calcium hydroxide (10). Urea + benzoate in the lowest doses, propionate in the higher concentration and calcium hydroxide were selected, considering the ethanol content (26.5, 27.2 and 7.4 g/kg DM, respectively), total DM loss (88, 46 and 58 g/kg DM, respectively) and digestibility (541, 496 and 516 g/kg DM, respectively) of the silages. Silages treated with these doses of additives and the untreated silage (80 d of storage) were fed (nine + seven d) to 16 castrated male sheep (Santa Inês) housed in metabolic cages. The silage with calcium hydroxide presented coefficients of apparent digestibility of DM (0.44), of NDF (0.4) and DM intake (20 g/kg live weight) in the higher levels. Calcium hydroxide was superior to propionate and urea + benzoate, considering alcoholic fermentation control and reduction of losses in the silage and the forages nutritional value.

O objetivo deste estudo foi indicar um aditivo para a ensilagem da cana-de-açúcar (Saccharum officinarum L.). Em um ensaio de laboratório, nove tratamentos foram aplicados (g de aditivo/kgde forragem fresca - FF) à cana-de-açúcar (RB867515) antes da ensilagem em minisilos (tubos de PVC de 15 x 30 cm) durante 78 d: sem tratamento; uréia (5) + benzoato de sódio (0,5); uréia (7,5) + benzoato (0,5); uréia (5) + benzoato (0,75); uréia (7,5) + benzoato (0,75); propionato de sódio (1, 2 e 4); hidróxido de cálcio (10). Uréia + benzoato nas doses mais baixas, propionato na dose mais alta e hidróxido de cálcio foram selecionados, considerando a concentração de etanol (26,5; 27,2 e 7,4 g/kgMS, respectivamente), perda total de MS (88, 46 e 58 g/kg MS, respectivamente) e digestibilidade (541, 496 e 516 g/kg MS, respectivamente) das silagens. Silagens tratadas com estas dosagens dos aditivos e silagem não tratada (80 d estocagem) foram fornecidas (nove + sete d) a 16 carneiros (Santa Inês) machos castrados mantidos em gaiolas metabólicas. A silagem com hidróxido de cálcio apresentou coeficientes de digestibilidade aparente da MS (0,44), da FDN (0,40) e de ingestão da MS (20 g/kg peso vivo) nos níveis mais altos. Hidróxido de cálcio foi superior ao propionato e à uréia + benzoato, considerando-se o controle da fermentação alcoólica, a redução de perdas e o valor nutritivo da silagem.

An overview of biotechnological production of propionic acid: from upstream to downstream processes

The increasing demand for propionic acid (PA) production and its wide applications in several industries, especially the food industry (as a preservative and satiety inducer), have led to studies on the low-cost biosynthesis of this acid. This paper gives an overview of the biotechnological aspects of PA production and introduces Propionibacterium as the most popular organism for PA production. Moreover, all process variables influencing the production yield, different simple and complex carbon sources, the metabolic pathway of production, engineered mutants with increased productivity, and modified tolerance against high concentrations of acid have been described. Furthermore, possible methods of extraction and analysis of this organic acid, several applied bioreactors, and different culture systems and substrates are introduced. It can be concluded that maximum biomass and PA production may be achieved using metabolically engineered microorganisms and analyzing the most significant factors influencing yield. To date, the maximum reported yield for PA production is 0.973 g·g-1, obtained from Propionibacterium acidipropionici in a three-electrode amperometric culture system in medium containing 0.4 mM cobalt sepulchrate. In addition, the best promising substrate for PA bioproduction may be achieved using glycerol as a carbon source in an extractive continuous fermentation. Simultaneous production of PA and vitamin B12 is suggested, and finally, the limitations of and strategies for competitive microbial production with respect to chemical process from an economical point of view are proposed and presented. Finally, some future trends for bioproduction of PA are suggested.

Chiral separation of aryloxyphenoxy-propionate herbicides in a permethyl-ß-cyclodextrin based column. Influence of temperature and mobile phase composition on enantioselectivity.

We used a permethyl-ß-cyclodextrin chiral stationary phase under reversed-phase conditions for the chiral separation of four aryloxyphenoxy-propionate herbicides (fenoxaprop-p-ethyl, quizalofop-p-ethyl and tefuryl, and haloxyfop-p-methyl) with mixtures of methanol, ethanol, 2-propanol, n-propanol, tert-butanol, or acetonitrile and water as mobile phases and investigated the influence of mobile phase composition and column temperature (from 0 to 50°C) on the separation. The retention factors (k) and selectivity factors (α) of all the herbicides investigated decreased with increasing temperature. The lnα versus 1/T and lnk versus 1/T plots for the enantiomers of the chiral pesticides were linear within the range of 0-50°C with all alcohol/water mixtures constituting the mobile phase, but the lnk versus 1/T plots were nonlinear for all the enantiomers chromatographed in acetonitrile/water mixtures. The thermodynamic parameters based on linear van't Hoff plots were calculated. The influence of temperature and mobile phase composition on the enantioseparation of the solutes has rarely been considered simultaneously. The temperature and the solvents used in the mobile phase, however, were found to have a profound effect on the enantioseparation of these herbicides.

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) production from biodiesel by-product and propionic acid by mutant strains of Pandoraea sp.

Pandoraea sp. MA03 wild type strain was subjected to UV mutation to obtain mutants unable to grow on propionic acid (PA) but still able to produce poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] from glycerol and PA at high 3HV yields. In shake flask experiments, mutant prp25 was selected from 52 mutants affected in the propionate metabolism exhibiting a conversion rate of PA into 3HV units of 0.78 g g-1 . The use of crude glycerol (CG) plus PA or valeric acid resulted in a copolymer with 3HV contents varying from 21.9 to 30 mol% and 22.2 to 36.7 mol%, respectively. Fed-batch fermentations were performed using CG and PA and reached a 3HV yield of 1.16 g g-1 , which is 86% of the maximum theoretical yield. Nitrogen limitation was a key parameter for polymer accumulation reaching up to 63.7% content and 18.1 mol% of 3HV. Henceforth, mutant prp25 is revealed as an additional alternative to minimize costs and support the P(3HB-co-3HV) production from biodiesel by-products. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1077-1084, 2017.

Evaluation of different methods for immobilization of Candida antarctica lipase B (CalB lipase) in polyurethane foam and its application in the production of geranyl propionate.

With the aim of studying the best method for the interaction of polyurethane (PU) foam and Candida antarctica lipase B, different methods of CalB immobilization were studied: adsorption (PU-ADS), bond (using polyethyleneimine) (PU-PEI), ionic adsorption by PEI with cross-linking with glutaraldehyde (PU-PEI-GA) and entrapment (PU). The characterization of immobilized enzyme derivatives was performed by apparent density and Fourier transform infrared spectroscopy. The free enzyme and enzyme preparations were evaluated at different pH values and temperatures. The highest enzyme activity was obtained using the PU method (5.52 U/g). The methods that stood out to compare the stabilities and kinetic parameters were the PU and PU-ADS. Conversions of 83.5 and 95.9 % for PU and PU-ADS derivatives were obtained, in 24 h reaction, using citronella oil and propionic acid as substrates.

Iron(III) chloride and diorganyl diselenides-mediated 6-endo-dig cyclization of arylpropiolates and arylpropiolamides leading to 3-organoselenyl-2H-coumarins and 3-organoselenyl-quinolinones.

Combination of iron(III) chloride and diorganyl diselenides was used for cyclization of arylpropiolates and arylpropiolamides in formation of 3-organoselenyl-2H-coumarins and 3-organoselenyl-quinolinones, respectively. Systematic study to determine the ideal conditions revealed that the two substrates reacted in the same way using identical reaction conditions. The versatility of this method has been demonstrated by extension of the best reaction conditions to substrate having a variety of substituents. Analyses of the optimization reaction also showed that diorganyl diselenides have a dual role by acting as cycling agent and base to restore the aromatic system. Mechanistic investigation studies and analyses of the products obtained have revealed that the cyclization reactions follow an initial 6-endo-dig process to give the six-membered heterocycles without involving an intramolecular ipso-cyclization route.

Modeling the coverage of an AFM tip by enzymes and its application in nanobiosensors.

A stochastic simulation of adsorption processes was developed to simulate the coverage of an atomic force microscope (AFM) tip with enzymes represented as rigid polyhedrons. From geometric considerations of the enzyme structure and AFM tip, we could estimate the average number of active sites available to interact with substrate molecules in the bulk. The procedure was exploited to determine the interaction force between acetyl-CoA carboxylase enzyme (ACC enzyme) and its substrate diclofop, for which steered molecular dynamics (SMD) was used. The theoretical force of (1.6±0.5) nN per enzyme led to a total force in remarkable agreement with the experimentally measured force with AFM, thus demonstrating the usefulness of the procedure proposed here to assist in the interpretation of nanobiosensors experiments.