Currently, there is a growing interest in transforming wastewater treatment plants (WWTPs) into resource recovery plants. Microorganisms in aerobic granular sludge produce extracellular polymeric substances (EPS), which are considered sustainable resources to be extracted and can be used in diverse applications. Exploring applications in other high-value materials, such as adhesives, will not only enhance the valorization potential of the EPS but also promote resource recovery. This study aimed to characterize a water-soluble fraction extracted from the EPS collected at the demonstration plant in the Netherlands based on its chemical composition (amino acids, sugar, and fatty acids) and propose a proof-of-concept for its use as an adhesive. This fraction comprises a mixture of biomolecules, such as proteins (26.6 ± 0.3%), sugars (21.8 ± 0.2%), and fatty acids (0.9%). The water-soluble fraction exhibited shear strength reaching 36–51 kPa across a pH range of 2–10 without additional chemical treatment, suggesting a potential application as an adhesive. The findings from this study provide insights into the concept of resource recovery and the valorization of excess sludge at WWTPs.@en

Natural Deep Eutectic Solvents (NADES) are composed of supramolecular interactions of two or more natural compounds, such as organic acids, sugars, and amino acids, and they are being used as a new media alternative to conventional solvents. In this study, a new application of NADES is presented as a possible technology for biofilm structural breaker in complex systems since the current solvents used for biofilm cleaning and extraction of biofilm components use hazardous solutions. The NADES (betaine:urea:water and lactic acid:glucose:water) were analyzed before and after the biofilm treatment by attenuated total reflection Fourier-transform infrared spectroscopy and fluorescence excitation-emission matrix spectroscopy. Our results indicate that the green solvents could solubilize up to ≈70 percent of the main components of the biofilms extracellular matrix. The solubilization of the biomolecules weakened the biofilm structure, which could enhance the biofilm solubilization and removal. The NADES have the potential to be an environment-friendly, green solvent to extract valuable compounds and break the main structure from the biofilm, leading to a greener method for extracellular polymeric substance (EPS) extraction and biofilm treatment in various water treatment systems.

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Under drought stress, Phytoseiulus persimilis females are able to lay drought-resistant eggs through an adaptive maternal effect. The mechanisms making these eggs drought resistant still remain to be investigated. For this purpose, we studied the physiological differences between drought-resistant and drought-sensitive eggs. We compared the volume and the surface-area-to-volume ratio (SA:V) of the eggs, their sex ratio, their chemical composition (by gas chromatography-mass spectrometry), their internal and external structure [by scanning electron microscope (SEM) and transmission electron microscope (TEM) images], and their developmental time. Our results show that drought-resistant and drought-sensitive eggs have a different chemical composition: drought-resistant eggs contain more compatible solutes (free amino acids and sugar alcohols) and saturated hydrocarbons than drought-sensitive eggs. This difference may contribute to reducing water loss in drought-resistant eggs. Moreover, drought-resistant eggs are on average 8.4% larger in volume, and have a 2.4% smaller SA:V than drought-sensitive eggs. This larger volume and smaller SA:V, probably the result of a higher water content, may make drought-resistant eggs less vulnerable to water loss. We did not find any difference in sex ratio, internal or external structure nor developmental time between drought-resistant and drought-sensitive eggs. These results mark the first step in the understanding of the strategies and the energetic costs involved in the production of drought-resistant eggs in P. persimilis females.

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The use of natural deep eutectic solvents (NADES) as multifunctional solvents for limonene bioprocessing was reported. NADES were used for the extraction of limonene from orange peel wastes, as solvent for the chemoenzymatic epoxidation of limonene, and as sacrificial electron donor for the in situ generation of H ₂ O ₂ to promote the epoxidation reaction. The proof-of-concept for this multifunctional use was provided, and the scope and current limitations of the concept were outlined.

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