Biogenic silver nanoparticles are synthesized through silver(I) reduction, which is promoted by biomolecules available in the biological world and mostly obtained from plant extracts, fungal bioproduction, and some bacteria. The exact mechanisms accounting for such oxidoreduction processes are not fully known. However, some studies have already mentioned oxidoreductases, cofactors (nicotinamide adenine dinucelotide hydrogen (NADH), dihydroflavine-adenine dinucleotid (FADH2)), and phenolic compounds, as the main reductive species engaged in the formation of silver(0) and silver nanoparticles (silver NPs) synthesis. Biosynthesis is a one-pot process that leads to stable silver NP colloids that, regarding their size, shape, and uniformity, can be successfully controlled; and show great stability when one takes into account their surface capping by some biomolecules that as well take part in their synthesis. Although great efforts have been made to feature capping biomolecules and their interactions with silver NP surfaces, knowledge of the quantity (exact number per cm2) and type of biomolecules that cap or surround silver NPs remains limited. The literature provides detailed information on protein capping, but it still shows gaps regarding many aspects of fine biophysical protein featuring. The reason why certain proteins prefer to interact with silver NP surface and form chemical bonds, whereas others rather have intermolecular interaction with the first layer of proteins remains unknown. Assessing capping proteins’ involvement in the bioactivity of biogenic silver NPs is another relevant research field. Certain proteins enhance bioactivity of silver NPs and lower toxicity; however, the way antimicrobial processes benefit from protein capping is yet to be discovered. Finally, biogenic silver NPs can be found both in the environment and in water; moreover, their additional activity and behavior must be known or, at least, hypothesized.

Our study was motivated by the large amount of crop residues produced in Brazil, which represent underutilized waste biomass and a serious threat to the environment because of the landfilling. For example, even though the corn crop is not popular in Brazil, it is produced in the area of around 18-20 million hectares with an average production of 5-6 t ha-1. That is the reason to seek for the crop residues value-added applications as proposed in the present study. Four Brazilian crop waste biomass: orange bagasse, corn husks, sugarcane straw and coffee residues were used for cellulose nanofibers (CNF) production. CNFs were prepared using alkali treatment, followed by bleaching with sodium chlorite and extraction with oxalic acid. All steps were applied under moderate conditions of temperature and pressure, such as temperature of 120 °C and below, water solutions with chemicals’ concentrations lower that 10% and short sonication pulses. CNFs with diameters in the range 50-70 nm were obtained and products from orange bagasse and corn husks presented high crystallinity indexes (CI), 0.72 and 0.75, respectively. The highest CNF yield was obtained from corn husks (38.5%) followed by sugarcane straw (24.0% with CI of 0.69). CNFs obtained from coffee residues showed a CI value of 0.65 after two bleaching steps. Different CNF morphologies were obtained according to the raw material. The four-crop waste biomass can be considered as excellent starting materials for CNF production in the four-steps process that adds new value to agro-industrial waste and might bring great economical valorization to Brazilian crops production.

Endogenous and environmental factors can influence the lipid contents of fishes among which, in the Amazon River, seasonal dynamics influences stand out. Herein, nine most consumed Amazonian fish species had their lipid composition evaluated in terms of effects of tissue, season and eating habits. Higher amounts of lipids were obtained from fish livers than dorsal muscles. Statistical analysis has shown that Amazonian fishes presented different lipid profiles according to their eating habits, which mainly comprised saturated fatty acids to distinguish detritivorous livers, and linolenic acid, cholesterol, polar lipids for carnivorous and piscivorous fish muscles. Furthermore, in Amazonian fish, some very important lipids for human nutrition were found, such as w-3 and w-6 fatty acids whose availability depended on the tissue metabolism and fishes’ eating habit along with the seasonal periods. For example, our findings indicated that the piscivorous fish C. monoculus presented higher levels of linoleic acid for livers than linolenic acid and the opposite occurred for muscles. The w-6 and w-3 fatty acids ratio was influenced by the season dynamic of the Amazon River and availability of food according to each specific eating habit, pointing mainly to the piscivorous fishes as the healthiest fish for human consumption.

This article reports on an easy-to-follow methodology for fish lipids analysis, including the biological sample collection, lipid extraction, sample preparation, nuclear magnetic resonance (NMR) spectroscopy analysis and statistical data analysis, with details on parameters used for the NMR analysis and the care needed in each step execution. As an example of the biological matrix of lipids, for the entire procedure, we have used two Amazonian fish samples. Phenotype factor was taken into account when lipid contents of the Amazonian fish samples were evaluated, such as fish-eating habits in distinct Amazon seasonal periods, the flood and the drought. Results demonstrated the applicability of NMR as a powerful and useful tool for fish oil analysis. The omnivorous (T. elongatus) and the piscivorous (C. monoculus) Amazonian fish differ in composition and distribution of lipids, which show differences not only because of the different eating habits between the two species, but also by the availability and quantity of food along the year, i.e., during the flood and drought Amazon periods.

A biomassa procedente do processamento de laranjas (CPWO) foi utilizada na produção de nanocelulose e do etanol da segunda geração. Primeiramente, vinte micro-organismos foram isolados da CPWO e suas capacidades de fermentação foram testadas. Dois destes, identificados como Candida parapsilosis IFM 48375 e NRRL Y-12969 (ATCC 22019), foram selecionados para a posterior fermentação. A biomassa foi destilada a vapor para o isolamento do óleo essencial (1,5% g g-1 de CPWO seco) e convertida em uma mistura de açúcares fermentáveis (40% g g-1 de CPWO seco) usando hidrólise ácida ou enzimática. Os hidrolisados foram fermentados utilizando micro-organismos isolados e a Saccharomyces cerevisiae. A levedura Candida parapsilosis IFM 48375 foi a mais eficiente na fermentação dos açúcares obtidos desta biomassa e os maiores rendimentos de bioetanol (21% g g-1 de CPWO seco) foram alcançados. A nanocelulose (2,5% g g-1 de CPWO seco) e as nanofibras (0,5% g g-1 de CPWO seco) foram isoladas partindo de bioresíduos vindo da hidrólise enzimática e da fermentação alcoólica e este resultado é o primeiro do gênero.

Citrus processing waste from oranges (CPWO) was explored for the production of nanocellulose and bioethanol. After the isolation of 20 microorganisms from CPWO, their fermentation abilities were screened and two microorganisms identified as Candida parapsilosis strains IFM 48375 and NRRL Y-12969 (ATCC 22019) were selected for a further fermentation. The CPWO was steam distilled for the isolation of essential oil (1.5% g g-1 of dry CPWO) and converted into a mixture of fermentable sugars (40% g g-1 of dry CPWO) using acid or enzymes hydrolyses. Hydrolyzates were fermented with three different yeast strains, the two Candida sp. and Saccharomyces cerevisiae. Candida parapsilosis strain IFM 48375 accomplished excellent results in ethanol production (21% g g-1 of dry CPWO) from CPWO, higher when compared to other strains. Nanocellulose (2.5% g g-1 dry CPWO) and nanofibers (0.5% g g-1 dry CPWO) were isolated from solid residues obtained from enzymatically treated and fermented CPWO. To the best of our knowledge, this work reports for the first time the nanocellulose production from CPWO.

The use of poorly water soluble molecules in pharmaceutical area has grown. Since these molecules exhibit low oral bioavailability, they are not used in intravenous administrations. Therefore, it is necessary to develop their new formulations with the aim to increase their oral bioavailabilities as to enable intravenous applications. One of the few possibilities in achieving this is a nanonization process that can produce crystals smaller than 1 μm by high pressure homogenization and without use of organic solvents. This mini-review describes technical aspects of the nanocrystal production, morphological aspects (polymorphisms), the market relevance of the nanocrystals products that are already in clinical phase or at the market, as well as, perspectives for the near future.