Kinetic and stoichiometric parameters in the fed-batch bioreactor production of poly(3-hydroxybutyrate) by Bacillus megaterium using different carbon sources.

This study investigates the effects of different strategies on poly(3-hydroxybutyrate)-P(3HB) production in a fed-batch bioreactor by Bacillus megaterium using candy industry effluent (CIE), sucrose, and rice parboiled water (RPW) as carbon sources. In biosynthesis, kinetic and stoichiometric parameters of substrate conversion into products and/or cells, productivity, instantaneous, and specific conversion rates were evaluated. The maximum concentration of P(3HB) was 4.00 g.L-1 (77% of the total dry mass) in 42 h of cultivation in minimal medium/RPW added with a carbon source based on CIE, demonstrating that the fed-batch provided an increase of approximately 22% in the polymer concentration and 32% in the overall productivity in relation to medium based on commercial sucrose. Fed-batch cultivation also had the advantage of avoiding the extra time required for inoculum preparation and sterilization of the bioreactor during the batch, which thereby increased the overall industrial importance of the process. Effluents from the candy, confectionery, and/or rice parboiling industries can be used as alternative substrates for P(3HB) production at a low cost.

Influence of redox potential on the accumulation of poly(3-hydroxybutyrate) by Bacillus megaterium.

The main goal of the present study was to evaluate the oxidation-reduction potential (ORP) on the production of poly(3-hydroxybutyrate) (P(3HB)) by Bacillus megaterium. Each microorganism has an optimal ORP range, and changes to the culture medium's ORP may redistribute the cell's metabolic flux, as such, the measurement and control of the ORP profile allows one to, in a way, manipulate the microbial metabolism, affecting the expression of certain enzymes and allowing for better control over the fermentative process. The ORP tests were carried out in a fermentation vessel coupled with an ORP probe, containing 1 L of mineral medium added with agroindustry byproducts (60% v/v of confectionery wastewater, and 40% v/v of rice parboiling water). The system's temperature was kept at 30 °C, with an agitation speed of 500 rpm. The vessel's airflow rate was controlled via a solenoid pump based on the ORP probe's data. Different ORP values were evaluated to verify their impact on biomass and polymer production. Cultures using OPR levels of 0 mV displayed the highest amounts of total biomass (5.00 g L-1) when compared to - 20 mV and - 40 mV (2.90 g L-1 and 0.53 g L-1, respectively). Similar results were also found for P(3HB)-to-biomass ratio, with polymer concentration being reduced when using ORP levels below 0 mV and with a maximum amount of polymer-to-biomass ratio of 69.87% after 48 h of culture. Furthermore, it was possible to observe that the culture's pH can also affect total biomass and polymer concentration, albeit to a lesser extent. Thus, when considering the data found during this study, it is possible to observe that ORP values can greatly impact B. megaterium cell's metabolism. Furthermore, the measurement and control of ORP levels may be an invaluable asset when trying to maximize polymer production under different culture conditions.

Effect of Extraction Time on the Yield, Chemical Composition, and Antibacterial Activity of Hop Essential Oil Against Lactic Acid Bacteria (Lactobacillus brevis and Lactobacillus casei) Beer Spoilage.

Hop essential oil (EO) generates interest for its antioxidant and antimicrobial properties, in addition to the volatile compounds that are responsible for the hop aroma in beer. Thus, the objective of this study was to evaluate the chemical composition, EO yield, and antibacterial activity of hop essential oil from hops of the Chinook variety against lactic acid bacteria (Lactobacillus brevis and Lactobacillus casei) at different times of extraction. EO extraction was performed by hydrodistillation at different times. By analyzing the chemical composition by gas chromatography and mass spectrometry, the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were determined. The major compounds of hop EO were α-humulene, ß-myrcene, and ß-caryophyllene, and the extraction yields were 0.67, 0.78, and 0.85% mass of EO per mass of hops pelletized hops (m/m), for extractions of 90, 180, and 300 min, respectively. The EO obtained in 90 min was efficient against L. casei at 2.5 mg/mL (MIC) and 5.0 mg/mL (MBC), and the 300 min one against L. brevis at 2.5 mg/mL (MIC) and 25 mg/mL (MBC). The antibacterial activity was affected by the chemical makeup of the oil, revealing that the hop EO extracted in 300 min was the most efficient among the other extraction times.

Recent updates to microbial production and recovery of polyhydroxyalkanoates.

The increasing use of synthetic polymers and their disposal has raised concern due to their adverse effects on the environment. Thus, other sustainable alternatives to synthetic plastics have been sought, such as polyhydroxyalkanoates (PHAs), which are promising microbial polyesters, mainly due to their compostable nature, biocompatibility, thermostability, and resilience, making this biopolymer acceptable in several applications in the global market. The large-scale production of PHAs by microorganisms is still limited by the high cost of production compared to conventional plastics. This review reports some strategies mentioned in the literature aimed at production and recovery, paving the way for the bio-based economy. For this, some aspects of PHAs are addressed, such as synthesis, production systems, process control using by-products from industries, and advances and challenges in the downstream. The bioplastics properties made them a prime candidate for food, pharmaceutical, and chemical industrial applications. With this paper, it is possible to see that biodegradable polymers are promising materials, mainly for reducing the pollution produced by polymers derived from petroleum.

Extraction of hops pelletized (Humulus lupulus) with subcritical CO2 and hydrodistillation: Chemical composition identification, kinetic model, and evaluation of antioxidant and antimicrobial activity.

Hop essential oil and hop extract using carbon dioxide (CO2) are products with high added value because they have bioactive and sensory properties. In this context, the objective of this study was to obtain and characterize essential oil and extracts from pelleted hops of El Dorado, Polaris, Hallertau Blanc and Callista varieties using hydrodistillation and subcritical CO2 extraction methods. Extraction yield ranged from 0.38 % to 1.97 % (m/m) for essential oils and from 8.76 % to 15.35 % (m/m) for extracts using subcritical CO2. The chemical compositions of the essential oils were mainly monoterpene (18.14 % to 29.91 %) and sesquiterpene (46.01 % to 59.03 %) hydrocarbons and for the extracts were sesquiterpene hydrocarbons (33.05 % to 71.90 %) and oxygenated sesquiterpenes (14.80 % to 34.89 %). The extracts showed better antioxidant activity than essential oils due to the presence of phenolic compounds and flavonoids. Hop extracts showed some antimicrobial activity, but essential oils did not demonstrate antimicrobial potential. Hop extracts obtained with subCO2 have the potential to be used in the brewing industry as a flavoring and as natural antioxidants.

Microencapsulation of Yarrowia lipolytica: cell viability and application in vitro ruminant diets.

Microencapsulation is an alternative to increase the survival capacity of microorganisms, including Yarrowia lipolytica, a widely studied yeast that produces high-value metabolites, such as lipids, aromatic compounds, biomass, lipases, and organic acids. Thus, the present study sought to investigate the effectiveness of different wall materials and the influence of the addition of salts on the microencapsulation of Y. lipolytica, evaluating yield, relationship with cell stability, ability to survive during storage, and in vitro application of ruminant diets. The spray drying process was performed via atomization, testing 11 different compositions using maltodextrin (MD), modified starch (MS) and whey protein concentrate (WPC), Y. lipolytica (Y. lipo) cells, tripolyphosphate (TPP), and sodium erythorbate (SE). The data show a reduction in the water activity value in all treatments. The highest encapsulation yield was found in treatments using MD + TPP + Y. lipo (84.0%) and WPC + TPP + Y. lipo (81.6%). Microencapsulated particles showed a survival rate ranging from 71.61 to 99.83% after 24 h. The treatments WPC + Y. lipo, WPC + SE + Y. lipo, WPC + TPP + Y. lipo, and MD + SE + Y. lipo remained stable for up to 105 days under storage conditions. The treatment WPC + SE + Y. lipo (microencapsulated yeast) was applied in the diet of ruminants due to the greater stability of cell survival. The comparison between the WPC + SE + Y. lipo treatment, wall materials, and the non-microencapsulated yeast showed that the microencapsulated yeast obtained a higher soluble fraction, degradability potential, and release of nutrients.

Active edible films based on green tea extract and gelatin for coating of fresh sausage.

The objective of this work was to develop, characterize and evaluate the application of active edible films based on gelatin and green tea extract in coating of fresh sausages. The green tea extract showed IC50 of 0.088 mg/mL and minimum inhibitory concentrations of 0.05 mg/mL for Listeria monocytogenes, 0.025 mg/mL for Staphylococcus aureus, 0.04 mg/mL for Escherichia coli, and >1.0 mg/mL for Salmonella enterica serovar Choleraesuis. The formulation with 15% (w/v) of gelatin and 30% (w/w) of glycerol showed better adhesion and appearance in the coating of the product. When using 1.0% of green tea extract, the lowest IC50, was obtained and the antioxidant activity was maintained for 35 days. There was a more accentuated decrease in pH and an increase in acidity and peroxide index in fresh sausages without film compared to those coated with the active film (1.0% of green tea extract) during storage. In addition, it was found that the use of active gelatin film (1.0% of green tea extract) kept the TBARS indexes of fresh sausage samples lower than the standard (without coating) and of films containing only gelatin, after 48 days of storage.

Chitosan and chitosan/PEG nanoparticles loaded with indole-3-carbinol: Characterization, computational study and potential effect on human bladder cancer cells.

Indole-3-carbinol (I3C) is a plant molecule known to be active against several types of cancer, but some chemical characteristics limit its clinical applications. In order to overcome these limitations, polymeric nanoparticles can be used as carrier systems for targeted delivery of I3C. In this study, chitosan and chitosan/polyethylene glycol nanoparticles (CS NP and CS/PEG NP, respectively) were prepared to encapsulate I3C by ionic gelation method. The polymeric nanoparticles were characterized by Dynamic Scattering Light (DLS), Zeta Potential (ZP), Fourier Transform Infrared (FTIR) spetroscopy, X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), and Field Emission Gun Scanning Electron Microscopy (FEG-SEM). I3C release testing was performed at an acidic media and the interactions between I3C and chitosan or PEG were evaluated by Density Functional Theory (DFT). Cytotoxicity of nanoparticles in bladder cancer T24 cell line was evaluated by the Methyl-thiazolyl-tetrazolium (MTT) colorimetric assay. The average size of the nanoparticles was observed to be in the range from 133.3 ± 3.7 nm to 180.4 ± 2.7 nm with a relatively homogeneous distribution. Samples had relatively high positive zeta potential values (between +20.3 ± 0.5 mV and + 24.3 ± 0.5 mV). Similar encapsulation efficiencies (about 80%) for both nanoparticles were obtained. Physicochemical and thermal characterizations pointed to the encapsulation of I3c. electron microscopy showed spherical particles with smooth or ragged surface characteristics, depending on the presence of PEG. The mathematical fitting of the release profile demonstrated that I3C-CS NP followed the Higuchi model whereas I3C-CS/PEG NP the Korsmeyer-Peppas model. Chemical differences between the nanoparticles as based on the I3C/CS or I3C/PEG interactions were demonstrate by computational characterization. The assessment of cell viability by the MTT test showed that the presence of both free I3C and I3C-loaded nanoparticles lead to statistically significant reduction in T24 cells viability in the concentrations from 500 to 2000 µM, when comparison to the control group after 24 h of exposure. Thus, CS and CS/PEG nanoparticles present as feasible I3C carrier systems for cancer therapy.

Nb-MCM-Type Mesoporous Material Synthesis Using Ionic Solid as Structure-Directing Agent for In Situ Lipase Immobilization.

MCM-41 and MCM-48 with niobium were successfully synthesized using 1-tetradecyl-3-methylimidazolium chloride ([C14MI]Cl) as a structure-directing agent. The best Si/Nb molar ratio was chosen (Si/Nb = 20) and the CALB enzyme was immobilized in situ in the synthesized Nb-MCM. SEM micrographs showed the formation of very regular spherical agglomerates with a diameter between 0.25 and 0.75 µm. The material presented a surface area of 954 and 704 m2/g and a pore volume of 0.321 and 0.286 cm3/g, for Nb-MCM-41 and Nb-MCM-48, respectively. Also, both materials showed a pore size of 2.261 nm. The number of recycles obtained for the CALB enzyme immobilized in Nb-MCM-41 and Nb-MCM-48 was 26 recycles with a residual activity of 49.62% and 16 recycles with a residual activity of 53.01%, respectively. For both materials, enzymatic activity remained stable for 5 months of storage at room temperature and refrigeration. The supports were able to catalyze the esterification reaction at 40, 60, and 80 °C, showing industrial application in reactions that require high temperatures. This methodology allows the preparation of new highly active and selective enzyme catalysts using niobium and [C14MI]Cl. Also, the new materials can provide greater viability in processes, ensuring a longer service life of catalysts. Graphical abstract.

Biological properties of functional flavoring produced by enzymatic esterification of citronellol and geraniol present in Cymbopogon winterianus essential oil.

The chemical composition and biological properties of citronella essential oil were modified by enzymatic esterification reaction of the major monoterpenic alcohols with cinnamic acid. The almost complete conversion of geraniol and citronellol present in the citronella (Cymbopogon winterianus) essential oil, into geranyl (99%) and citronellyl (98%) cinnamates was obtained after 48 hours of reaction using a molar ratio of 3:1 (cinnamic acid/alcohol), lipase concentration (Novozym 435) of 15% (w/w) and 70 °C. The esterified oil showed higher antimicrobial activity against Staphylococcus aureus bacteria resistant to oxacillin and penicillin and also greater larvicidal activity against Aedes aegypti larvae compared to unesterified oil. The results concerning the evaluation of toxicity against Artemia salina and cytotoxicity against monkey kidney epithelial cells also showed the superiority of the esterified oil.

Extraction and characterization of phytochemical compounds from araçazeiro (Psidium cattleianum) leaf: Putative antioxidant and antimicrobial properties.

Underexplored species have phytochemical potential for pharmacological and nutraceutical applications. The fruits of such species, including aracá (Psidium cattleianum Sabine), are rich in specialized metabolites with putative antioxidant and antimicrobial activity; therefore, the leaves of these species are also a potential source of bioactive compounds. In this study, araçazeiro leaves were extracted using an aqueous infusion (Al) and a pressurized liquid extraction system with water (PLE-W), ethanol (PLE-E), and 1:1 water:ethanol ratio combination (PLE-W:E). PLE-W:E yielded a greater diversity of extracted compounds. Nonetheless, all extracts showed inhibitory activity against pathogenic Gram-positive and Gram-negative bacteria and antioxidant activity in the in vitro thiobarbituric acid reactive substances (TBARS) and reactive oxygen species (ROS) assays with rat brain and yeast model systems. Thus, araçazeiro leaves can be exploited as a promising source of bioactive compounds.

Newly Isolated Penicillium sp. for Cellulolytic Enzyme Production in Soybean Hull Residue

Abstract (1) Background: The aim of this study was to evaluate the production and partial characterization of xylanase and avicelase by a newly isolated Penicillium sp. in solid-state fermentation, using soybean hulls as substrate. (2) Methods: Temperature, time, number of spores, and substrate moisture on xylanase and avicelase bioproduction were evaluated, maximizing activity with 30°C, 1x106 spores/g substrate, 14 and 7 days of fermentation with 70 and 76% substrate moisture contents, for xylanase and avicelase, respectively. (3) Results: Different solvents, temperatures, and agitation in the enzymatic extraction were evaluated, obtaining higher activities, 430.77 and 26.77 U/g for xylanase and avicelase using 30 min extraction and 0.05 M citrate buffer solution (pH 4.5 ), respectively at 60°C and 175 rpm and 50°C and 125 rpm. The optimum pH and temperature for enzymatic activity determination were 5.3 and 50°C. Enzyme extract stability was evaluated, obtaining higher stability with pH between 4.5 and 5.5, higher temperature of up to 40°C. The kinetic thermal denaturation (Kd), half-life time, D-value, and Z-value were similar for both enzymes. The xylanase Ed value (89.1 kJ/mol) was slightly lower than the avicelase one (96.7 kJ/mol), indicating higher thermostability for avicelase. (4) Conclusion: In this way, the production of cellulases using alternative substrates is a way to reduce production costs, since they represent about 10% of the world demand of enzymes, with application in animal feed processing, food production and breweries, textile processing, detergent and laundry production, pulp manufacturing and the production of biofuels.

High pressure extraction of olive leaves (Olea europaea): bioactive compounds, bioactivity and kinetic modelling.

In this study, the extraction yield, the mathematical modeling of pressurized liquid extraction (PLE) kinetics with sub- and supercritical carbon dioxide (SC-CO2) of olive leaves (Olea europaea) and the biological activity of the extracts were evaluated. The extraction with PLE was conducted isobarically (10.3 MPa), varying the temperature (20, 40 and 60 °C) and the solvent (ethyl acetate, acetone, ethanol, ethanol:water-80:20, v:v), solvent flow (2 mL min-1) and time (110 min) and the extractions with SC-CO2, varying the temperature between 20 and 60 °C and the pressure between 8 and 25 MPa, keeping the time constant (210 min) and the CO2 flow of 2 mL min-1. In the extracts, antioxidant activity, total phenolic and flavonoid contents and oleuropein were evaluated. The highest total extract yield in the PLE was 30.91% at 60 °C, 10.3 MPa using ethanol:water (80:20, v:v). The yield obtained using the supercritical fluid was 0.68% at 60 °C and 25 MPa. The PLE extract obtained with ethanol at 60 °C presented the highest concentration of total phenolic content (386.42 mg GAE g-1 extract), total flavonoids content (33.43 mg CAT g-1 extract), oleuropein (73.65 mg g-1 extract) and antioxidant activity (82.87%). The overall extraction curves were modeled using the well-established Sovová model and kinetic extraction model based on the Brunauer-Emmett-Teller theory of adsorption. Both kinetic models used were able to correlate well with the experimental data with slightly better results obtained by the former. The alternative PLE extraction technique investigated in this work was found to be suitable for the extraction of olive leaves after short times of extraction obtaining an extract with high biological activities.

Water absorption and dripping of chicken breast and carcasses during pre-cooling in an industrial system.

This study aimed to evaluate the parameters that influence the water absorption and drip of chicken carcasses due to the processing and pre-cooling of the meat in an industrial chiller. A total of 1,179 chickens were sampled during industrial processing to evaluate the influence of variables, validate the parameters, and conduct histological analysis. The best parameters for guaranteeing absorption levels and drip tests within acceptable limits on chicken carcasses were total residence time of 60 min (in the pre-chiller, chiller 1, and chiller 2); air pressure of chillers at 0.5 bar; the abdominal opening of carcasses at a maximum of 2 cm. These parameters did not influence the protein content, moisture/protein ratio, pH, or lipid content. The validation of the parameters and the histological analysis performed after each cooling stage showed that the most significant structural changes occurred in the pre-chiller, where the temperature of carcasses and water was higher, which contributes to greater absorption.

Development and Structural Behaviour of Soybean Gelato.

The aim of this study is to elaborate and evaluate structural characteristics of soybean gelato by varying the content of soybean protein concentrate (2.95 to 17.05%) and vegetable fat (7.95 to 22.05%) using experimental design. The replacement of milk by hydrosoluble extract and soybean protein concentrate presented itself as an alternative to gelato production with unique characteristics, especially in terms of protein, solubility, viscosity, melting point, overrun and acceptability. The addition of up to 5% (m/V) protein concentrate, 14% (by volume) soybean hydrosoluble extract, and 15% (by mass) vegetable fat to gelato formulations resulted in better structural characteristics, with viscosity ranging from 0.45-0.70 Pa∙s at 10 °C, a non-Newtonian behaviour and protein stability (total protein content 8.44% and solubility 41%). Soybean gelato structural analysis using X-ray diffraction revealed 15° and 35° diffraction angles at 2Θ, characterizing the crystalline part of the product. The thermal analyses showed four bands of mass loss in the temperature range of 40-600 °C, characterizing loss of moisture, decomposition of the soy protein and the fat/emulsifier of the formulations. Thus, the soybean gelato is an innovative product, lactose and milk protein-free with outstanding characteristics for the general public, mainly, for the populations with intolerance to such components.

Evaluation of the TLC quantification method and occurrence of deoxynivalenol in wheat flour of southern Brazil.

The study evaluated a QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) extraction method for use with a TLC quantification procedure for deoxynivalenol (DON). It also surveyed DON occurrence in wheat flour from the southern region of Brazil. Forty-eight wheat flour samples were analysed, divided into 2 different harvest lots, each consisting of 24 different brands. The detection and quantification limits of the method were 30 and 100 ng of DON on the TLC plate. The various concentrations of DON presented high linearity (R2 = 0.99). A negative matrix effect (-28%) of the wheat flour was verified, with suppression of the chromatographic signal of DON, and 80.2-105.4% recovery. The TLC method was reliable for DON evaluation, with a coefficient of variation of less than 10%. High-performance liquid chromatography of lot 2 samples confirmed the presence of DON in all samples identified DON-positive by the TLC technique. Of the 48 wheat flour samples in lots 1 and 2 analysed by TLC, 33.3 and 45.8% of the samples respectively were above the Brazilian legislation limit. Correlations were observed between the water activity and DON content, and between the fungal count and moisture content of the wheat flours.