Acetylsalicylic acid biosorption onto fungal-bacterial biofilm supported on activated carbons: an investigation via batch and fixed-bed experiments.

This study reports on acetylsalicylic acid (ASA) biosorption onto fungal-bacterial biofilm supported on two types of activated carbons (one commercial type made of coconut fibers, CAC, and one other manufactured from fruit rinds of Hymenaea stigonocarpa Mart., HYAC, which after biofilm inoculation, they were named CAC-b and HYAC-b), via batch and fixed-bed experiments. These materials were characterized by BET Specific Surface Area and Scanning Electronic Microscopy (SEM). Biosorption onto HYAC-b was 57.2% higher than HYAC. Despite presenting the highest biosorption capacity over time (qt = 85.4 ± 0.82 mg g-1), CAC-b had a lower increase in efficiency (32.4%) compared to CAC. Kinetic data from the biosorption experiments responded well to the pseudo-first-order model thus suggests the predominance of physisorption, while without biofilm presence, there was a better agreement with the pseudo-second-order model, suggesting chemisorption. The possible interaction mechanism of ASA to biofilm was attributed to ionic forces between the drug in anionic form and eventual presence of cationic by-products of the biologically active surface metabolism. Biosorption equilibrium data responded better to the Sips model and CAC-b presented the highest biosorption capacity (qe = 292.4 ± 2.01 mg g-1). A combination of faster volumetric flow rates, higher inlet concentrations and shorter beds accelerated the breakthrough time of ASA biosorption in the fixed-bed experiments. These operational conditions affected C/Co ratio in the following magnitude order: volumetric flow rate < inlet concentration < bed height. Breakthrough data responded better to the modified dose-response model compared to Thomas and Yoon-Nelson models.

RR2 dye adsorption to Hymenaea courbaril L. bark activated carbon associated with biofilm.

This study addressed the removal performance of RR2 from aqueous solutions in adsorption columns experiments by comparing the potential of activated carbon alone (ACA) and microbially inoculated (MIAC), prepared from barks of a largely available tree in Brazilian Cerrado biome, Hymenaea courbaril L. or "Jatobá," presenting the kinetics, isotherms, breakthrough curves, and dissolved organic carbon removal. ACA presented strong interaction to RR2 dye, evidenced at the first 20 min when absorbance already attained 66.4%. The removal percentage gradually increased with time and the equilibrium occurred around 91.7% within 120 min. Langmuir model best fitted the isotherm data, indicating a maximum adsorption capacity of 4.068 mg g-1 for the amount of 0.5 g of adsorbent. The Langmuir's model parameters KL, RL, and R2 corresponded to 0.0234 L mg-1, 0.4159, and 0.9663, respectively, indicating a favorable adsorption process (0 < RL < 1). The experiments in adsorption columns revealed maximum adsorption capacities of 14.38 and 11.43 mg g-1 for MIAC and ACA, respectively, where the microbial activity favorably retarded the adsorption breakpoint in approximately 20 min and enhanced the RR2 consumption in 25.8%. Effectiveness of DOC removal attained above 90% for both ACA and MIAC, reducing the content from 86.1 to 7.84 mg L-1 and 4.82 mg L-1, respectively.

Efeito de frações tânicas sobre parâmetros biológicos e nutricionais de Spodoptera frugiperda (Lepidoptera: Noctuidae) / Effect of tanical fractions on biological and nutritional parameters of Spodoptera frugiperda (Lepidoptera: Noctuidae)

Conduziu-se este trabalho, com o objetivo de quantificar taninos condensados presentes nas cascas do caule de Ochroma pyramidalis (Bombacaceae), Schinus terebinthifolius (Anacardiaceae), Enterolobium contortisiliquum (Fabaceae) e Peltophorum dubium (Fabaceae) e verificar o efeito de frações tânicas dessas espécies sobre parâmetros biológicos e nutricionais de S. frugiperda. A partir das cascas das espécies vegetais se prepararam extratos, dos quais alíquotas foram tomadas para a quantificação dos taninos. Em seguida, os extratos foram submetidos a fracionamento para a obtenção das frações tânicas, que foram incorporadas à dieta artificial e oferecidas para lagartas de S. frugiperda. Todas as espécies vegetais estudadas apresentaram taninos condensados, sendo que S. terebinthifolius apresentou menor quantidade desses compostos. A fração tânica de P. dubium causou redução no peso das lagartas e pupas, diminuição na sobrevivência de S. frugiperda durante as fases larval e pupal, e acarretou menor consumo alimentar, além de prolongar a duração das fases imaturas desse inseto. O tratamento com S. terebinthifolius causou redução na percentagem de sobrevivência, durante a fase de pupa. Pupas provenientes de lagartas que receberam tratamento com a fração de E. contortisiliquum tiveram aumento no seu período de desenvolvimento. Lagartas alimentadas com a fração proveniente de P. dubium apresentaram a menor taxa de crescimento relativo (RGR), menor eficiência de conversão do alimento digerido (ECD) e maior custo metabólico (CM). A digestibilidade aproximada (AD) foi maior para os tratamentos com as frações tânicas de P. dubium e S. terebinthifolius.

The objective of this study was to quantify condensed tannins present in the stem bark of Ochroma pyramidalis (Bombacaceae), Schinus terebinthifolius (Anacardiaceae), Enterolobium contortisiliquum (Fabaceae) and Peltophorum dubium (Fabaceae) and to verify the effect of tannic fractions of these species on biological and nutritional parameters of S. frugiperda. Extracts were prepared from the barks of the plant species and aliquots were taken from them to quantify the tannins. The extracts were then submitted to fractionation to obtain the tannic fractions, which ones were incorporated into an artificial diet and offered to the larvae of S. frugiperda. All the studied species showed condensed tannins, and S. terebinthifolius showed the lowest amount of these compounds. The tannin fraction of P. dubium caused a reduction in the weight of larvae and pupae, decreased the survival of S. frugiperda during the larval and pupal stages and led to a reduction of intake, beyond to extend the duration of immature stages of this insect. The treatment with S. terebinthifolius caused a reduction in the survival percentage during the pupal stage. Pupae from larvae that received the treatment with the fraction of E. contortisiliquum had an increase in its development period stage. Larvae fed with the fraction from P. dubium showed the lowest relative growth rate (RGR), lower efficiency of conversion of ingested food (ECI) and a higher metabolic cost (CM). The approximate digestibility (AD) was higher for the treatments with tannic fractions of P. dubium and S. terebinthifolius.