Hydrogels based on lignin extracted from cashew apple bagasse and its application in antimicrobial wound dressings.

Hydrogels are versatile materials with a three-dimensional network structure that can retain water and release bioactive compounds. They have found applications in various fields, including agriculture, biomaterial synthesis, and pharmaceuticals. Incorporating natural antimicrobial compounds into hydrogels is a promising approach to developing non-toxic biomedical materials, particularly for wound healing dressings. It was evaluated the extraction and use of cashew apple bagasse lignin (CAB-Lig) due to its healing, anti-inflammatory, and antimicrobial properties for producing a hydrogel-based bandage. The extraction process involved acid and alkali treatments followed by precipitation. The antimicrobial potential of CAB-Lig was evaluated at different concentrations for formulating hydrogels. Hydrogels containing 0.1 % and 3 % lignin showed high swelling and liquid retention abilities. The 3 % lignin hydrogel exhibited effectiveness against Escherichia coli and Staphylococcus aureus. Incorporating CAB-Lig into the hydrogel structure improved its mechanical properties, making it more suitable for application as a bandage. Moreover, the extracted lignin showed low toxicity, indicating its safe use. A bandage was formulated by combining the CAB-Lig-based hydrogel with polyester, which possessed antimicrobial properties and demonstrated biocompatibility (L929 and HaCat cells). The results confirmed the potential of CAB-Lig for synthesizing hydrogels and dressings with antimicrobial properties, offering a sustainable solution for utilizing lignocellulosic biomass.

Analysis of gunshot residues from nontoxic ammunition: a contribution to health and environmental analysis.

This study's aim was to determine the presence, as well as to evaluate the health and environmental impacts, of chemical elements from firearm shots during shooter practice at outdoor shooting ranges, both in the environment and on the shooters' hands. Two high-precision devices were used for measuring suspended particles that are released during discharge of Taurus PT 100 .40 caliber pistols. The analysis of collected data allowed the identification of specific distribution patterns of samples that were adsorbed. Moreover, samples were collected from the opisthenar area of the hand to investigate both the occurrence and deposition of particles and chemical elements through scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS). The results indicate that copper, lead, and zinc concentration profiles will be able to delimit and reveal more precise details regarding shots made with nontoxic ammunition (NTA). In particular, the residual graphic analysis indicated that the majority of metal deposited in the shooter's hand is zinc. Further, the metals barium and lead also were detected. Due to the exposure to these elements, it could be concluded that engineering controls and administrative management should be sought in order to avoid human overexposure and environmental release of these airborne toxic metals.

ß-Galactosidase from Kluyveromyces lactis: Characterization, production, immobilization and applications - A review.

A review on the enzyme ß-galactosidase from Kluyveromyces lactis is presented, from the perspective of its structure and mechanisms of action, the main catalyzed reactions, the key factors influencing its activity, and selectivity, as well as the main techniques used for improving the biocatalyst functionality. Particular attention was given to the discussion of hydrolysis, transglycosylation, and galactosylation reactions, which are commonly mediated by this enzyme. In addition, the products generated from these processes were highlighted. Finally, biocatalyst improvement techniques are also discussed, such as enzyme immobilization and protein engineering. On these topics, the most recent immobilization strategies are presented, emphasizing processes that not only allow the recovery of the biocatalyst but also deliver enzymes that show better resistance to high temperatures, chemicals, and inhibitors. In addition, genetic engineering techniques to improve the catalytic properties of the ß-galactosidases were reported. This review gathers information to allow the development of biocatalysts based on the ß-galactosidase enzyme from K. lactis, aiming to improve existing bioprocesses or develop new ones.

Polylactic acid production from biotechnological routes: A review.

Polylactic acid (PLA) has been highlighted as an important polymer due to its high potential for applicability in various areas, such as in the chemical, medical, pharmaceutical or biotechnology field. Very recently, studies have reported its use as a basic component for the production of personal protective equipment (PPE) required for the prevention of Sars-Cov-2 contamination, responsible for the cause of coronavirus disease, which is currently a major worldwide sanitary and social problem. PLA is considered a non-toxic, biodegradable and compostable plastic with interesting characteristics from the industrial point of view, and it emerges as a promising product under the concept of "green plastic", since most of the polymers produced currently are petroleum-based, a non-renewable raw material. Biotechnology routes have been mentioned as potential methodologies for the production of this polymer, especially by enzymatic routes, in particular by use of lipases enzymes. The availability of pure lactic acid isomers is a fundamental aspect of the manufacture of PLA with more interesting mechanical and thermal properties. Due to the technological importance that PLA-based polymers are acquiring, as well as their characteristics and applicability in several fields, especially medical, pharmaceutical and biotechnology, this review article sought to gather very recent information regarding the development of research in this area. The main highlight of this study is that it was carried out from a biotechnological point of view, aiming at a totally green bioplastic production, since the obtaining of lactic acid, which will be used as raw material for the PLA synthesis, until the degradation of the polymer obtained by biological routes.

The ß-galactosidase immobilization protocol determines its performance as catalysts in the kinetically controlled synthesis of lactulose.

In this paper, 3 different biocatalysts of ß-galactosidase from Kluyveromyces lactis have been prepared by immobilization in chitosan activated with glutaraldehyde (Chi_Glu_Gal), glyoxyl agarose (Aga_Gly_Gal) and agarose coated with polyethylenimine (Aga_PEI_Gal). These biocatalysts have been used to catalyze the synthesis of lactulose from lactose and fructose. Aga-PEI-Gal only produces lactulose at 50 °C, and not at 25 or 37 °C, Aga_Gly_Gal was unable to produce lactulose at any of the assayed temperatures while Chi_Glu_Gal produced lactulose at all assayed temperatures, although a lower yield was obtained at 25 or 37 °C. The pre-incubation of this biocatalyst at 50 °C permitted to obtain similar yields at 25 or 37 °C than at 50 °C. The use of milk whey instead of pure lactose and fructose produced an improvement in the yields using Aga_PEI_Gal and a decrease using Chi_Glu_Gal. The operational stability also depends on the reaction medium and of biocatalyst. This study reveals how enzyme immobilization may greatly alter the performance of ß-galactosidase in a kinetically controlled manner, and how medium composition influences this performance due to the kinetic properties of ß-galactosidase.

Development of a purification process via crystallization of xylitol produced for bioprocess using a hemicellulosic hydrolysate from the cashew apple bagasse as feedstock.

Xylitol was biotechnologically produced by Kluyveromyces marxianus ATCC36907 using the hemicellulosic hydrolysate of the cashew apple bagasse (CABHH). Sequentially, the present study investigated the recovery and purification of xylitol evaluating different antisolvents [ethanol, isopropanol and the ionic liquid 2-hydroxyl-ethylammonium acetate (2-HEAA)], their proportion in the medium (10-90% v/v), and their cooling rate (VC 0.25-0.50 °C/min). These processes were contrasted with the crystallization process of commercial xylitol. This study is the first to assess xylitol crystallization using a protic ionic liquid. The hydrolysate obtained from a mild treatment with sulfuric acid contained mainly glucose and xylose at concentrations of 15.7 g/L and 11.9 g/L, respectively. With this bioprocess, a maximum xylitol production of 4.5 g/L was achieved. The performance of the investigated antisolvents was similar in all conditions evaluated in the crystallization process of the commercial xylitol, with no significant difference in yields. For the crystallization processes of the produced xylitol, the best conditions were: 50% (v/v) isopropanol as antisolvent, cooling rate of 0.5 °C/min, with a secondary nucleation of yield and purity of 69.7% and 84.8%, respectively. Under the same linear cooling rate, using ethanol, isopropanol or the protic ionic liquid 2-hydroxyl-ethylammonium acetate (2-HEAA), crystallization did not occur, probably due to the presence of carbohydrates not metabolized by the yeast in the broth, which influences the solubility curve of xylitol. With the results of this work, a possible economical and environmentally friendly process of recovery and purification of xylitol from CABHH could be proposed.

Hybrid neural network modeling and particle swarm optimization for improved ethanol production from cashew apple juice.

A hybrid neural model (HNM) and particle swarm optimization (PSO) was used to optimize ethanol production by a flocculating yeast, grown on cashew apple juice. HNM was obtained by combining artificial neural network (ANN), which predicted reaction specific rates, to mass balance equations for substrate (S), product and biomass (X) concentration, being an alternative method for predicting the behavior of complex systems. ANNs training was conducted using an experimental set of data of X and S, temperature and stirring speed. The HNM was statistically validated against a new dataset, being capable of representing the system behavior. The model was optimized based on a multiobjective function relating efficiency and productivity by applying the PSO. Optimal estimated conditions were: S0 = 127 g L-1, X0 = 5.8 g L-1, 35 °C and 111 rpm. In this condition, an efficiency of 91.5% with a productivity of 8.0 g L-1 h-1 was obtained at approximately 7 h of fermentation.

Simultaneous hydrolysis of cheese whey and lactulose production catalyzed by ß-galactosidase from Kluyveromyces lactis NRRL Y1564.

ß-Galactosidase was produced by the yeast Kluyveromyces lactis NRRL Y1564 in cheese whey supplemented with yeast extract under the optimal temperature of 30 °C, delivering an enzymatic activity of 4418.37 U/gcell after 12 h of process. In order to develop more stable biocatalysts, the enzyme produced by fermentation was immobilized on 2.0% w/v chitosan activated with glutaraldehyde, epichlorohydrin or glycidol, producing a highly active and stable biocatalyst capable of hydrolyzing lactose and producing lactulose simultaneously. The biocatalyst obtained by immobilization in chitosan-glutaraldehyde showed high storage stabilities (100% of its activity when stored at 4 °C 105 days). Regarding the milk lactose hydrolysis by both the soluble and the immobilized enzyme, the conversions obtained were 38.0% and 42.8%, respectively. In this study, by using a biocatalyst deriving from enzyme immobilization to chitosan support, a lactulose production of 17.32 g/L was also possible.

Optimized acid hydrolysis of the polysaccharides from the seaweed Solieria filiformis (Kützing) P.W. Gabrielson for bioethanol production / Hidrólise ácida otimizada dos polissacarídeos da macroalga Solieria filiformis (Kützing) P.W. Gabrielson para produção de bioetanol

The seaweeds are bio-resource rich in sulfated and neutral polysaccharides. The tropical seaweed species used in this study (Solieria filiformis), after dried, shows 65.8% (w/w) carbohydrate, 9.6% (w/w) protein, 1.7% (w/w) lipid, 7.0% (w/w) moisture and 15.9% (w/w) ash. The dried seaweed was easily hydrolyzed under mild conditions (0.5 M sulfuric acid, 20 min.), generating fermentable monosaccharides with a maximum hydrolysis efficiency of 63.21%. Galactose and glucose present in the hydrolyzed were simultaneously fermented by Saccharomyces cerevisiae when the yeast was acclimated to galactose and cultivated in broth containing only galactose. The kinetic parameters of the fermentation of the seaweed hydrolyzed were Y(P/S) = 0.48 ± 0.02 g.g−1, PP = 0.27 ± 0.04 g.L−1.h−1, η = 94.1%, representing a 41% increase in bioethanol productivity. Therefore, S. filiformis was a promising renewable resource of polysaccharides easily hydrolyzed, generating a broth rich in fermentable monosaccharides for ethanol production.

As algas marinhas são recursos naturais ricos em polissacarídeos sulfatados e neutros. A espécie de macroalga tropical utilizada neste estudo (Solieria filiformis) apresentou teores de carboidratos de 65,8% (m/m), proteínas de 9,6% (m/m), lipídios de 1,7% (m/m), umidade de 7,0% (m/m) e 15,9 % (m/m) de cinzas. A macroalga seca foi facilmente hidrolisada em condições brandas, na presença de ácido sulfúrico 0,5 M, por 20 min, produzindo monossacarídeos fermentáveis com uma eficiência de hidrólise máxima de 63,21%. A galactose e a glicose presentes no hidrolisado foram fermentadas simultaneamente por Saccharomyces cerevisiae, após aclimatação da levedura cultivada em meio contendo apenas galactose como fonte de carbono. Os parâmetros cinéticos da fermentação do hidrolisado algáceo pela levedura aclimatada a galactose foram Y(P/S) = 0,48 ± 0,02 g.g-1, PP = 0,27 ± 0,04 g.L- 1.h-1, η = 94,1%. Portanto, a macroalga S. filiformis se mostrou um recurso renovável promissor como fonte de polissacarídeos facilmente hidrolisados, gerando um meio nutritivo rico em glucose e galactose para a produção de etanol.

Mathematical modeling of the ethanol fermentation of cashew apple juice by a flocculent yeast: the effect of initial substrate concentration and temperature.

In this work, the effect of initial sugar concentration and temperature on the production of ethanol by Saccharomyces cerevisiae CCA008, a flocculent yeast, using cashew apple juice in a 1L-bioreactor was studied. The experimental results were used to develop a kinetic model relating biomass, ethanol production and total reducing sugar consumption. Monod, Andrews, Levenspiel and Ghose and Tyagi models were investigated to represent the specific growth rate without inhibition, with inhibition by substrate and with inhibition by product, respectively. Model validation was performed using a new set of experimental data obtained at 34 °C and using 100 g L-1 of initial substrate concentration. The model proposed by Ghose and Tyagi was able to accurately describe the dynamics of ethanol production by S. cerevisiae CCA008 growing on cashew apple juice, containing an initial reducing sugar concentration ranging from 70 to 170 g L-1 and temperature, from 26 to 42 °C. The model optimization was also accomplished based on the following parameters: percentage volume of ethanol per volume of solution (%V ethanol/V solution), efficiency and reaction productivity. The optimal operational conditions were determined using response surface graphs constructed with simulated data, reaching an efficiency and a productivity of 93.5% and 5.45 g L-1 h-1, respectively.

Pretreatment of cashew apple bagasse using protic ionic liquids: Enhanced enzymatic hydrolysis.

To enhance the enzymatic digestibility of cashew apple bagasse (CAB) feedstock in order to produce sugar fermentation-derived bioproducts, the CAB was subjected to three different pretreatments with the ionic liquid 2-hydroxyl-ethylammonium acetate (2-HEAA) and characterized by FTIR, NMR and chemical methods. All conditions were able to delignify CAB, however the best lignin removal (95.8%) was achieved through the method performed with 8.7% w/w of CAB/2-HEAA ratio at 130°C for 24h. Although the cellulose crystallinity has been increased in CAB treated with the ionic liquid, but this fact did not influence its digestibility. Nevertheless, the pretreatment with 2-HEAA enhanced significantly the cellulose digestibility, increasing the glucose yield from 48 to 747.72mgglucose/gCAB. Furthermore, 2-HEAA pretreatment was efficient even with reused ionic liquid, obtaining high glucose concentration.

Enhanced enzymatic hydrolysis and ethanol production from cashew apple bagasse pretreated with alkaline hydrogen peroxide.

The effect of combinations and ratios between different enzymes has been investigated in order to assess the optimal conditions for hydrolysis of cashew apple bagasse pretreated with alkaline hydrogen peroxide (the solids named CAB-AHP). The separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) processes were evaluated in the ethanol production. The enzymatic hydrolysis conducted with cellulase complex and ß-glucosidase in a ratio of 0.61:0.39, enzyme loading of 30FPU/g(CAB-AHP) and 66CBU/g(CAB-AHP), respectively, using 4% cellulose from CAB-AHP, turned out to be the most effective conditions, with glucose and xylose yields of 511.68 mg/g(CAB-AHP) and 237.8 mg/g(CAB-AHP), respectively. Fermentation of the pure hydrolysate by Kluyveromyces marxianus ATCC 36907 led to an ethanol yield of 61.8kg/ton(CAB), corresponding to 15 g/L ethanol and productivity of 3.75 g/( Lh). The ethanol production obtained for SSF process using K. marxianus ATCC 36907 was 18 g/L corresponding to 80% yield and 74.2kg/ton(CAB).

Ultrasound-assisted production of biodiesel and ethanol from spent coffee grounds.

This study evaluates the production of biodiesel and ethanol from spent coffee grounds (SCG). The extraction of oil from SCG, biodiesel production and ethanol production processes were studied. The liquid-to-solid ratio and temperature were evaluated in the ultrasound-assisted extraction of the oil from SCG. The highest yield (12%) was obtained using 4 mL g(-1) liquid-to-solid ratio at 60°C for 45 min. The process to produce biodiesel showed a yield of 97% into fatty acid methyl esters (FAME). The highest glucose yield (192 mg g SCG(-1)) was obtained by hydrolysis with 0.4 mol L(-1) sulfuric acid at 121°C for 15 min. The hydrolysate was used as fermentation medium for ethanol production by Saccharomyces cerevisiae obtaining 19.0 g L(-1) at 10h of process of ethanol with a yield of ethanol and productivity of 0.50 g g(-1) and 1.90 g L(-1)h(-1), respectively. Spent coffee grounds were considered a potential feedstock for biodiesel and ethanol production.

Alkaline hydrogen peroxide pretreatment of cashew apple bagasse for ethanol production: study of parameters.

The alkaline hydrogen peroxide (AHP) pretreatment of cashew apple bagasse (CAB) was evaluated based on the conversion of the resultant cellulose into glucose. The effects of the concentration of hydrogen peroxide at pH 11.5, the biomass loading and the pretreatment duration performed at 35°C and 250 rpm were evaluated after the subsequent enzymatic saccharification of the pretreated biomass using a commercial cellulase enzyme. The CAB used in this study contained 20.56 ± 2.19% cellulose, 10.17 ± 0.89% hemicellulose and 35.26 ± 0.90% lignin. The pretreatment resulted in a reduced lignin content in the residual solids. Increasing the H2O2 concentration (0-4.3% v/v) resulted in a higher rate of enzymatic hydrolysis. Lower biomass loadings gave higher glucose yields. In addition, no measurable furfural and hydroxymethyl furfural were produced in the liquid fraction during the pretreatment. The results show that alkaline hydrogen peroxide is effective for the pretreatment of CAB.

Ethanol production from cashew apple bagasse: improvement of enzymatic hydrolysis by microwave-assisted alkali pretreatment.

In this work, the potential of microwave-assisted alkali pretreatment in order to improve the rupture of the recalcitrant structures of the cashew able bagasse (CAB), lignocellulosic by-product in Brazil with no commercial value, is obtained from cashew apple process to juice production, was studied. First, biomass composition of CAB was determined, and the percentage of glucan and lignin was 20.54 ± 0.70% and 33.80 ± 1.30%, respectively. CAB content in terms of cellulose, hemicelluloses, and lignin, 19.21 ± 0.35%, 12.05 ± 0.37%, and 38.11 ± 0.08%, respectively, was also determined. Results showed that, after enzymatic hydrolysis, alkali concentration exerted influence on glucose formation, after pretreatment with 0.2 and 1.0 mo L(-1) of NaOH (372 ± 12 and 355 ± 37 mg g(glucan)(-1) ) when 2% (w/v) of cashew apple bagasse pretreated by microwave-assisted alkali pretreatment (CAB-M) was used. On the other hand, pretreatment time (15-30 min) and microwave power (600-900 W) exerted no significant effect on hydrolysis. On enzymatic hydrolysis step, improvement on solid percentage (16% w/v) and enzyme load (30 FPU g (CAB-M) (-1) ) increased glucose concentration to 15 g L(-1). The fermentation of the hydrolyzate by Saccharomyces cerevesiae resulted in ethanol concentration and productivity of 5.6 g L(-1) and 1.41 g L(-1) h(-1), respectively.

Cashew apple bagasse as a source of sugars for ethanol production by Kluyveromyces marxianus CE025.

The potential of cashew apple bagasse as a source of sugars for ethanol production by Kluyveromyces marxianus CE025 was evaluated in this work. This strain was preliminarily cultivated in a synthetic medium containing glucose and xylose and was able to produce ethanol and xylitol at pH 4.5. Next, cashew apple bagasse hydrolysate (CABH) was prepared by a diluted sulfuric acid pretreatment and used as fermentation media. This hydrolysate is rich in glucose, xylose, and arabinose and contains traces of formic acid and acetic acid. In batch fermentations of CABH at pH 4.5, the strain produced only ethanol. The effects of temperature on the kinetic parameters of ethanol fermentation by K. marxianus CE025 using CABH were also evaluated. Maximum specific growth rate (µ(max)), overall yields of ethanol based on glucose consumption [Formula: see text] and based on glucose + xylose consumption (Y ( P/S )), overall yield of ethanol based on biomass (Y ( P/X )), and ethanol productivity (P (E)) were determined as a function of temperature. Best results of ethanol production were achieved at 30°C, which is also quite close to the optimum temperature for the formation of biomass. The process yielded 12.36 ± 0.06 g l(-1) of ethanol with a volumetric production rate of 0.257 ± 0.002 g l(-1) h(-1) and an ethanol yield of 0.417 ± 0.003 g g(-1) glucose.

Clarified cashew apple juice as alternative raw material for biosurfactant production by Bacillus subtilis in a batch bioreactor.

Clarified cashew apple juice was evaluated as carbon source for surfactin production by Bacillus subtilis LAMI005 isolated from the tank of chlorination at the Wastewater Treatment Plant on Campus do Pici (WWTP-PICI) in the Federal University of Ceará, Brazil. The highest surfactin concentration using clarified cashew apple juice (CCAJ) supplemented with mineral medium (MM-CCAJ) was 123 mg/L, achieved after 48 h of fermentation. Almost 2-fold less than the amount produced using mineral medium supplemented with 10 g/L of glucose and 8.7 g/L of fructose (MM-GF). However, critical micelle concentration of the biosurfactants produced using MM-CCAJ was 2.5-fold lower than the one produced using MM-GF, which indicates it is a more efficient biosurfactant. Surface tension decreased from 38.50 +/- 0.0 to 29.00 +/- 0.0 dyne/cm when B. subtilis was grown on MM-CCAJ media (24.68% of reduction on surface tension) and remained constant up to 72 h. Emulsification index was 51.15 and 66.70% using soybean oil and kerosene, respectively. Surfactin produced in MM-CCAJ showed an emulsifying activity of, respectively, 1.75 and 2.3 U when n-hexadecane or soybean oil was tested. However, when mineral medium supplemented with 10 g/L of glucose (MM-G) was used an emulsifying activity of 2.0 and 1.75 U, with n-hexadecane and soybean oil, respectively, was obtained. These results indicate that it is feasible to produce surfactin from CCAJ, a renewable and low-cost carbon source.

Enzymatic hydrolysis and fermentation of pretreated cashew apple bagasse with alkali and diluted sulfuric Acid for bioethanol production.

The aim of this work was to optimize the enzymatic hydrolysis of the cellulose fraction of cashew apple bagasse (CAB) after diluted acid (CAB-H) and alkali pretreatment (CAB-OH), and to evaluate its fermentation to ethanol using Saccharomyces cerevisiae. Glucose conversion of 82 +/- 2 mg/g CAB-H and 730 +/- 20 mg/g CAB-OH was obtained when 2% (w/v) of solid and 30 FPU/g bagasse was used during hydrolysis at 45 degrees C, 2-fold higher than when using 15 FPU/g bagasse, 44 +/- 2 mg/g CAB-H, and 450 +/- 50 mg/g CAB-OH, respectively. Ethanol concentration and productivity, achieved after 6 h of fermentation, were 20.0 +/- 0.2 g L(-1) and 3.33 g L(-1) h(-1), respectively, when using CAB-OH hydrolyzate (initial glucose concentration of 52.4 g L(-1)). For CAB-H hydrolyzate (initial glucose concentration of 17.4 g L(-1)), ethanol concentration and productivity were 8.2 +/- 0.1 g L(-1) and 2.7 g L(-1) h(-1) in 3 h, respectively. Hydrolyzates fermentation resulted in an ethanol yield of 0.38 and 0.47 g/g glucose with pretreated CAB-OH and CAB-H, respectively. Ethanol concentration and productivity, obtained using CAB-OH hydrolyzate, were close to the values obtained in the conventional ethanol fermentation of cashew apple juice or sugar cane juice.

Evaluation of cashew apple juice for the production of fuel ethanol.

A commercial strain of Saccharomyces cerevisiae was used for the production of ethanol by fermentation of cashew apple juice. Growth kinetics and ethanol productivity were calculated for batch fermentation with different initial sugar (glucose + fructose) concentrations. Maximal ethanol, cell, and glycerol concentrations were obtained when 103.1 g L(-1) of initial sugar concentration was used. Cell yield (Y (X/S)) was calculated as 0.24 (g microorganism)/(g glucose + fructose) using cashew apple juice medium with 41.3 g L(-1) of initial sugar concentration. Glucose was exhausted first, followed by fructose. Furthermore, the initial concentration of sugars did not influence ethanol selectivity. These results indicate that cashew apple juice is a suitable substrate for yeast growth and ethanol production.