This study reports the synthesis and characterization of a supramolecular composite comprised of carbon dots (CDots) embedded within net-poly[(α-cyclodextrin)-ν-(citric acid)] (α-CD/CA/CDots) for the removal and detection of toluene and xylene from aqueous media. The remarkable stability of CDots within the composite enables the preservation of photoluminescence properties for prolonged storage and extended UV-light irradiation. As demonstrated, following the adsorption of both organic compounds, the composite detected them in the aqueous medium due to a fluorescence quenching mechanism. Spectroscopic analyses reveal that the accessible Stern-Volmer quenching constants for toluene and xylene are K_SVa = 15.4 M^-1 and K_SVa = 10.3 M^-1, respectively. As a result, the α-CD/CA/CDots composite were sensitive to the tested volatile organic compounds (LOD_toluene = 3.7 mg/L and LOD_xylene = 4.9 mg/L). Optimal conditions for toluene and xylene adsorption were found, allowing to achieve noticeable adsorption capabilities (q_e(toluene) = 68.9 and q_e(xylene) = 48.2 mg/g) and removal efficiencies exceeding 70%. Different characterization techniques confirmed the successful synthesis of the composite and elucidated the interaction mechanisms between the adsorbent and the tested compounds. In summary, the multifunctionality demonstrated by the α-CD/CA/CDots composite ranks it as an efficient and promising adsorbent and detection probe for this class of water contaminants.

Biossurfactantes (BS) são moléculas de relevância industrial significativa, reconhecidas por suas propriedades tensoativas e potencial para produção por microrganismos que utilizam fontes alternativas de carbono e energia. O cacau (Theobroma cacao L.), fruto amazônico amplamente utilizado como matéria-prima na produção de chocolate, representa um recurso alternativo exemplar. Apesar da falta de valor econômico atribuído aos resíduos provenientes do processamento do cacau, esses subprodutos podem ser substratos valiosos para a produção de BS. Este estudo avaliou a eficácia da bactéria Pseudomonas aeruginosa BM02 na produção de BS, usando resíduos de cacau como matéria-prima, bem como investigou o potencial do BS como agente dispersante de óleo. O BS bruto exibiu uma concentração de ramnolipídios de 3,06 g/L e índice de emulsificação de 60%, influenciando significativamente na capacidade de dispersão do óleo de motor, que atingiu 2,5 cm2/min após 10 minutos. Esses resultados evidenciam a viabilidade, inovação e sustentabilidade da utilização de resíduos de cacau como matéria-prima para na produção de BS, com aplicações promissoras para biorremediação de áreas contaminadas por hidrocarbonetos. Ademais, essa abordagem contribui diretamente para a economia circular na Amazônia, pois a utilização sustentável de resíduos agroindustriais demonstra potencial para aumentar o valor agregado dentro da cadeia de produção local, proporcionando, assim, implicações sociais importantes ao promover o crescimento econômico na região.

Processing economically and socio-culturally significant Amazonian fruits—andiroba (Carapa guianensis Aubl.), açai (Euterpe oleracea Mart.), and babassu (Attalea speciosa Mart. ex Spreng.)—generates substantial biomass waste, posing critical environmental and waste management challenges. This study explored the valorization of these abundant residual biomasses as sustainable feedstocks for biosurfactant production by bacterium Pseudomonas aeruginosa P23G-02, while simultaneously profiling their nutritional value and broader implications for a circular bioeconomy. Through liquid fermentation, biosurfactants were produced at an approximate yield of 6 mg/mL. The isolated biosurfactants exhibited favorable properties, including emulsification indices of around 60% and surface tension reduction to below 30 mN/m, with the andiroba-derived biosurfactant identified as a rhamnolipid type. Nutritional profiling of the residues revealed significant energy values, reaching up to 656 kcal/100 g, with açai and babassu residues being carbohydrate-rich (exceeding 80%), and andiroba residues exhibiting a high lipid profile (up to 57%). These distinct compositions critically influenced biosurfactant yield. These findings underscore the viability of Amazonian fruit biomass as valuable resources for developing eco-friendly bioproducts and innovative waste management solutions. While highlighting a promising pathway for circular bioeconomy development, future research should address biosafety and explore alternative microbial hosts for applications in sensitive sectors such as food and nutrition.