Pseudomonas aeruginosa has great intrinsic antimicrobial resistance limiting the number of effective antibiotics. Thus, other antimicrobial agents such as silver nanoparticles (AgNPs) are considered potential agents to help manage and prevent infections. AgNPs can be used in several applications against bacteria resistant to common antibiotics or even multiresistant bacteria such as P. aeruginosa. This study assessed the antimicrobial activity of commercial 10 nm AgNPs on two hospital strains of P. aeruginosa resistant to a large number of antibiotics and a reference strain from a culture collection. All strains were susceptible to 5 µg/mL nanoparticles solution. Reference strains INCQS 0230 and P.a.1 were sensitive to AgNPs at concentrations of 1.25 and 0.156 µg/mL, respectively; however, this was not observed for hospital strain P.a.2, which was more resistant to all antibiotics and AgNPs tested. Cytotoxicity evaluation indicated that AgNPs, up to a concentration of 2.5 µg/mL, are very safe for all cell lines tested. At 5.0 µg/mL, AgNPs had a discrete cytotoxic effect on tumor cells HeLa and HepG2. Results showed the potential of using AgNPs as an alternative to conventional antimicrobial agents that are currently used, and a perspective for application of nanosilver with antibiotics to enhance antimicrobial activity.

Polyhydroxyalkanoates (PHAs) are biodegradable and renewable polymers produced by a wide range of bacterial groups. New microbial bioprospection approaches have become an important way to find new PHA producers and new synthesized polymers. Over the past years, bacteria belonging to actinomycetes group have become known as PHA producers, such as Nocardia and Rhodococcus species, Kineosphaera limosa Liu et al. 2002, and, more recently, Streptomyces species. In this paper, we disclose that there are more actinobacteria PHA producers in addition to the genera cited. Some unusual genera, such as Streptoalloteichus , and some genera frequently present in soil, such as Streptacidiphilus , have been found. Thirty-four isolates were able to accumulate poly(3-hydroxybutyrate) and a number of these have traces of poly(3-hydroxyvalerate) when cultivated on glucose or glucose and casein as carbon source. Furthermore, some strains showed traces of medium chain length PHA. Transmission electron microscopy demonstrated that the PHA accumulation occurs in hyphae and spores.

Fructooligosaccharides (FOSs) are carbohydrates of high nutritional value with various prebiotic properties. Optimizing their production process is of significant interest for expanding commercial-scale production. This review discusses the properties and potential applications of FOSs, addressing production challenges and providing an economic market analysis. Bibliometric analysis of data concerning the functional properties, production, purification, and applications of FOSs revealed an over 87% increase in the number of worldwide publications from 2012 to 2022, rising from 88 to 165. Furthermore, contributions from ninety-three countries were identified up to 2024, with Brazil ranking first, with 326 publications. Furthermore, Aureobasidium sp. and Aspergillus sp. have shown the best results for FOS production, with reported conversion in the order of 0.66 g FOS/g sucrose. Nevertheless, the formation of by-products or co-products requiring separation from the medium remains a challenge. Activated carbon, cation exchange resins, and zeolites are highlighted as key adsorbents, with the adsorption process achieving FOS purity exceeding 90%. Furthermore, membrane technology is identified as a more efficient and promising separation method. Addressing these limitations will facilitate the further expansion of the growing global FOS market, promoting a sustainable approach and their integration with biorefineries, which can enable the development of a wider range of value-added products.