Reactive Black 5 (RB5) is one of the synthetic reactive dyes most used in the textile industry, due to its solubility in water and reactive groups which form covalent bonds within the fiber. In the process of dyeing fabrics, however, it is estimated that 12-14% of dyes are released into the effluent. This work evaluated the biodegradation of RB5 dye, adsorbed in polyurethane foam, by basidiomycetes (Phanerochaete chrysosporium ATCC 24725, Pleurotus ostreatus and Pleurotus floridae). Results were evaluated considering the partial- or total medium discoloration, the adsorption capacity of the dye in the polyurethane foam (PUF) and the respirometric measurements. The results showed that Phanerochaete chrysosporium was able to partially degrade 50 mg L-1 of RB5 in pH 6.0, when cultivated in Petri dishes. When this microorganism was cultivated in PUF cubes saturated with RB5 solution (50 mg L-1, pH 6.0), CO2 production reached an accumulated value of 2.16 mg on the fifteenth day, revealing the growth of the microorganism and consequently the contaminant degradation, which was used as the source of nutrients.
Any bioassay to test new chemically synthesized larvicides or phytolarvicides against Culicidae and more harmful mosquito species, such as Aedes aegypti and Aedes albopictus, which specifically transmit dengue, yellow fever, chikungunya viral fevers as well as Zika virus, or Anopheles gambiae, a vector for malaria and philariasis, requires thousands of well-developed larvae, preferably at the fourth instar stage. The natural morphogenetic cycle of Aedes spp., in the field or in the laboratory, may extend to 19 days at room temperature (e.g., 25°C) from the first permanent contact between viable eggs and water and the last stage of larval growth or metamorphosis into flying adults. Thus, accelerated sequential molting is desirable for swifter bioassays of larvicides. We achieved this goal in Aedes aegypti with very limited strategic and low-cost additions to food, such as coconut water, milk or its casein, yeast extract, and to a lesser extent, glycerol. The naturally rich coconut water was excellent for quickly attaining the population of instar IV larvae, the most advanced one before pupation, saving about a week, for subsequent larvicidal bioassays. Diluted milk, as another food source, allowed an even faster final ecdysis and adults are useful for mosquito taxonomical purpose.
Phytobiomasses, given the qualitative and quantitative dominance of polysaccharides, are a dominant wealth available in nature. Cellulose and hemicelluloses from softwoods, hardwoods and grasses, starch from tubercles and roots, pectins from fruits and gums from some seeds may be explored as such or following acid or alkaline pretreatments as well enzymatic deconstruction, and even simple chemical derivatization toward more added-value products. A general view in the chemistry of these valuable polymers is here broached, following a sharper focus on acid pretreatments for L(h)C-ligno(hemi) cellulosic materials from sugarcane and other feedstocks. Our particular experience using a gentler proton donor but keeping very advantageous aspects for polysaccharide chemo/biotechnological processing-thermopressurized diluted phosphoric acid (oPA)-is presented with a more detailed description as a result of its validity for the hydrolytic deconstruction of hemicelluloses-heteroxylans and heteromannans, cassava starch, dahlia inulin and mixed glucans from microalgae cell walls. The opportunity of NOs-nutraceutical oligosacchrides-generation from these particular glycopolymers is also shortly commented.
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