RESUMO
This study aims to investigate whether the assassin snail Anentome helena may serve as a biological control agent of Bithynia siamensis goniomphalos, the 1st intermediate host of Opisthorchis viverrini. Experiments were carried out in the laboratory, and the results found that A. helena showed the variation and selection of mollusc prey. A. helena can consume B. siamensis goniomphalos, which is remarkable because this snail can compete with other snails and could be used as a biological control. The consumption rate of the predator was compared, and it was found that A. helena prefers to consume Indoplanorbis exustus, followed by Pomacea canaliculata, Melanoides tuberculata, Filopaludina sumatrensis speciosa, Lymnaea sp., and B. siamensis goniomphalos. This is the first report of an experimental study controlling B. siamensis goniomphalos using A. helena. Our data imply that A. helena can control the B. siamensis goniomphalos population with good results, especially in the absence of other snail species.
Assuntos
Opisthorchis , Caramujos , Controle Biológico de VetoresRESUMO
Deep Eutectic Solvents (DES) are used as reaction media for lipase-catalyzed esterifications in continuous devices. In particular, DES may be useful for lipophilization-like reactions involving substrates with unpaired solubilities. Aspects to be considered are the viscosity of the solvent, as well as the stability of the enzyme in the non-conventional media. The viscosity can be decreased by adding buffer as cosolvent (up to 20% v/v) and keeping the non-conventional nature. Lipases can be stabilized by following a double immobilization pattern, comprising CLEA formation and entrapment in LentiKats®. The low viscosity and high stability of the CLEA-LK-lipase enable the use of DES under flow conditions.
Assuntos
Solventes Eutéticos Profundos , Lipase , Catálise , Esterificação , Lipase/metabolismo , Solventes , ViscosidadeRESUMO
Lipase immobilization using adsorption on magnetic nanoparticles, cross-linked enzyme aggregates (CLEA), and a combination of both techniques was investigated. Experimental designs were used for the optimization of the immobilization observing that the pH and ionic strength play a principal role during the lipase immobilization and its activity. For adsorption on magnetic nanoparticles and CLEA synthesis the optimal condition was pH and 100 mM. Besides, during the CLEA synthesis, glutaraldehyde concentration showed to be a significant effect on the enzyme activity. A comparison between a magnetic CLEA prepared with (Lip@mCLEA) and without (mCLEA) biological functionalized magnetic nanoparticles was made observing that the use of functionalized support showed the best performance activity. All biocatalytic systems developed gives to the enzyme thermal stability between 45 and 70 °C, being Lip@mCLEA the more stable biocatalyst. Similar behavior was observed at different pH, where both Lip@mCLEA and mCLEA showed stability at a range of pH 5 to 8. The immobilized biocatalysts showed the same affinity of the subtract that the free enzyme suggested that the enzyme structure not modified the active site. The combination of both types of immobilization show evidenced the importance of the biological functionalization of the support when magnetic CLEA is produced.
Assuntos
Enzimas Imobilizadas/química , Proteínas Fúngicas/química , Lipase/química , Nanopartículas de Magnetita/química , Candida/enzimologia , Reagentes de Ligações Cruzadas/química , Estabilidade Enzimática , Enzimas Imobilizadas/metabolismo , Compostos Férricos/química , Proteínas Fúngicas/metabolismo , Lipase/metabolismoRESUMO
In the present study, we prepared two different magnetic biocatalysts of pectinase and cellulase: carrier-free magnetic CLEAs (CLEA-MP*) and immobilization on glutaraldehyde-activated magnetite (Enz-Glu-MP*). The biocatalysts were compared to their magnetic properties, immobilization parameters, stability and grape juice clarification. Enz-Glu-MP* presented higher magnetic properties than CLEA-MP*, whereas this presented higher surface area and pore volume. The KM of the enzyme immobilized on Enz-Glu-MP* was 25.65mM, lower in comparison to the CLEA-MP* (33.83mM). On the other hand, CLEA-MP* was the most active and stable biocatalyst, presenting higher recovered activity (33.4% of cellulase), higher thermal stability (2.39 stabilization factor) and improved reusability (8cycles). The integration of magnetic technology with enzymatic immobilization emerges as a possibility to increase the recover and reuse of biocatalysts for application in juice technology.
Assuntos
Celulase/química , Celulase/metabolismo , Óxido Ferroso-Férrico/química , Sucos de Frutas e Vegetais/análise , Poligalacturonase/química , Poligalacturonase/metabolismo , Vitis/química , Biocatálise , Estabilidade Enzimática , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Glutaral/química , Cinética , Solubilidade , TemperaturaRESUMO
Polyvinyl alcohol-pectin (PVA-P) films containing enrofloxacin and keratinase were developed to treat wounds and scars produced by burns and skin injuries. However, in order to prevent enzyme inactivation at the interface between the patch and the scars, crosslinked enzyme aggregates (CLEAs) from a crude extract of keratinase produced by Paecilomyces lilacinus (LPSC#876) were synthesized by precipitation with acetone and crosslinking with glutaraldehyde. Soluble vs. CLEA keratinase (K-CLEA) activities were tested in 59% (v/v) hydrophobic (isobutanol and n-hexane) and hydrophilic (acetone and dimethylsulfoxide) solvents mixtures. K-CLEA activity was 1.4, 1.7 and 6.6 times higher in acetone, n-hexane and isobutanol than the soluble enzyme at 37 °C after 1 h of incubation, respectively. K-CLEA showed at least 45% of enzyme residual activity in the 40-65 °C range, meanwhile the soluble biocatalyst was fully inactivated at 65 °C after 1h incubation. Also, the soluble enzyme was completely inactivated after 12 h at pH 7.4 and 45 °C, even though K-CLEA retained full activity. The soluble keratinase was completely inactivated at 37 °C after storage in buffer solution (pH 7.4) for 2 months, meanwhile K-CLEAs kept 51% of their activity. K-CLEA loaded into polyvinyl alcohol (PVA) and PVA-P cryogels showed six times lower release rate compared to the soluble keratinase at skin pH (5.5). Small angle X-ray scattering (SAXS) analysis showed that K-CLEA bound to pectin rather than to PVA in the PVA-P matrix.