Knowledge of the decomposition dynamics of aboveground phytomass and its release of nutrients in mixtures of cover crops as well as the impact on the soil tillage system is fundamental for the sustainable management of agroecosystems. This work aimed to evaluate whether soil tillage and the choice of cover crops cultivated in the interrows can be technological strategies to increase dry biomass production, increase the capacity to add carbon, and improve macronutrient cycling in a mango (Mangifera indica L.) orchard in a semi-arid environment. The field experiment (sixth year) consisted of two soil tillage systems (NT-no tillage and CT-conventional tillage) combined with three plant mixtures (PM1-75 % leguminous + 25 % grasses and oilseed species, PM2-25 % leguminous + 75 % grasses and oilseed species, and SV-spontaneous vegetation). Phytomass production and nutrient accumulation were not affected by the soil tillage system, but PM1 had the highest phytomass production and accumulations of C, N, and K, and it was significantly superior to SV. Regardless of the type of plant mixture, cultivated or spontaneous, soil tillage increased the rates of phytomass decomposition and nutrient release evaluated for 315 days after the cover plant management. The PM1 had the highest rates of decomposition and release of P and K, followed by PM2 and SV. There was no difference between the mixtures for the release of N, Ca, and Mg. The use of a mixture of cover crops, regardless of the predominance of leguminous or non-leguminous species, and a no-tillage system were technological strategies that could be adopted to favor the addition of soil carbon and nutrient cycling in fruit agroecosystems in the Brazilian semi-arid region. Spontaneous vegetation, due to its capacity to accumulate nutrients and the recalcitrant characteristics of its phytomass, has the potential to cycle nutrients and keep the soil covered. In addition, spontaneous vegetation should be better investigated because it is a low-cost strategy in agroecosystem designs.

β-Glucosidases (BGLs) belong to the group of enzymes of cellulases and act in the last stage of cellulose degradation, releasing glucose molecules, eliminating the inhibitory effect of cellobiose. This study focused on the production, characterization, and application of BGL from Moniliophthora perniciosa in the hydrolysis of pretreated sugarcane bagasse (3% NaOH + 6% Na 2 SO 3 ), with varying enzymatic loads and reaction times. The enzyme showed an optimum pH of 4.5 and 60 • C. It was stable at all temperatures analyzed (50-90 • C) and retained about 100% of its activity at 50 • C after 60 min of incubation. Among the ions analyzed, BaCl 2 increased BGL activity 9.04 ± 1.41 times. The maximum production of reducing sugars (89.15%) was achieved after 48 h with 10 mg of protein.

Cellulases are important enzymes in cellulose degradation that occurs in nature, this degradation involves a system of extracellular multienzymes and have wide application. The construction of a high-quality system for the production of these enzymes is important for its application in the process of saccharification of biomass involved in the biofuel production process. Several species of fungi are capable of synthesizing and secreting high amounts of cellulase, most studies with fungal species use linearized plasmid, since these are encompassed to chromosomal DNA, improving its stability and expression efficiency. Advances in the production of recombinant enzymes focus on the search for industrially viable microorganisms capable of producing enzymes under various conditions, expressing them in a highly efficient manner, aiming at the synthesis of several copies of genes and a strong promoter. To resay these restrictions, molecular biology combined with recombinant DNA technology is a viable tool in enzymatic production. In subsequent topics, the production of endoglucanases, exoglucanases and β-glucosidase of fungi cloned in Escherichia coli, Pichia pastoris and other different expression systems will be addressed.

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