The main objective of this work was to evaluate the effects of ultrasound irradiation on the activity of a commercial amylase. A central composite design was carried out to assess the effects of temperature and pH on the enzyme activity in the presence and absence of ultrasound irradiation. The activation energy, the influence of treatment time as well as the substrate concentration on enzyme activity were also determined in the presence and absence of ultrasound irradiation. The results demonstrated that the effect of temperature was less pronounced in the presence of ultrasound, resulting in a decreasing of about 80% in the activation energy in comparison with the value obtained in the absence. The enzyme showed activities about 3 times higher for temperatures up to 40 °C in the presence of ultrasound. The pH negatively affected the activity in the presence of ultrasound, whereas in the absence a positive effect was verified. The ultrasound irradiation is a promising technology to be used in enzymatic reaction due to its positive effects on enzyme activity.

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The potential of cell-wall degrading enzymes (chitinase, β-1,3 glucanase, endo-cellulase and exocellulase) in the control of M. javanica in vitro and in vivo was investigated in this study. The enzymes were produced by solid-state fermentation using Beauveria bassiana, Trichoderma harzianum and Metarhizium anisopliae, microorganisms that are used in the biological control of agricultural pests. The bioproducts were efficient in the treatments in vitro, presenting high indexes of egg hatching inhibition (66.7-87.0%) and mortality of juveniles (40.0-90.0%). The bioproduct containing enzymes from B. bassiana presented the most promising results. In vivo treatments with all bioproducts on lettuce and tomato cultures during initial stages of plant development demonstrated excellent nematicidal effects in relation to the water-treated control. On lettuce, final egg counts and juveniles in the control treatment were 141 and 452% higher than in treatments containing bioproducts, respectively. The index of penetration of M. javanica on tomato roots was 348% higher in the control treatment than in the treatments using bioproducts. The bioproducts evaluated in this study were efficient in the control of nematodes both in treatments in vitro and in vivo. The results obtained open a new perspective for the use of bioproducts containing cell-wall degrading enzymes for the control of nematodes in agriculture.

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