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Studies on B. terribiliscultivation have great economic and environmental relevance but are scarcely addressed in the literature. This article analyzes and compares, for the first time, the growth and metabolite productivity of B. terribilisin closed and open systems. The effect of nitrogen and phosphorus reduction on B. terribilis’ main metabolites was evaluated with a 22full factorial design, using 25, 50, and 75% of the standard concentration of these nutrients in the CHU13 medium. Proteins, carbohydrates, lipids, pigments, and hydrocarbons were extracted and quantified. It is the first time that B. terribilishydrocarbons were extracted and characterized, using an innovative methodology validated by GC-MS. Lipids were characterized by GC-FID. The possible applications of B. terribilisoils were described. The maximum specific growth rate obtained was 0.49 day−1with raceway cultivation. The stress condition increased lipids and hydrocarbons up to 49% and 29%, respectively, but the percentage of proteins decreased from 32 to 26%. The percentage of carbohydrates (15%) and pigments (0.41–0.86%) remained similar in the stressed and non-stressed cultivation. B. terribilisoils are suitable for biofuel synthesis, as it is composed of long-chain hydrocarbons and a higher amount of saturated and monounsaturated fatty acids. This study helps fill the gap of information about cultivation, stress, and composition of B. terribilis, supporting decision-making on the cultivation parameters and applications of this microalgae in a biorefinery context.

Polymeric hydrogels are crosslinked networks that form three-dimensional materials, offering unique tailored properties and diverse applications. Cellulose is a natural biopolymer abundant in hydroxyl groups, which holds great potential for hydrogel synthesis via chemical and physical crosslinking. Cellulose-based hydrogels possess potential advantageous characteristics, which enable their use in several fields, such as environmental, medical, agriculture, and most recently in energy fields. Nevertheless, challenges related to mechanical properties and degradation of these polymers persist. To address these limitations, the incorporation of multiple networks in cellulose hydrogels has been explored, combining the desirable features of each type of network to enhance overall performance. Hydrogels can be classified into various types of networks, including single crosslinking (physical or chemical), double-crosslinked hydrogels, grafted hydrogels, semi-interpenetrating polymeric networks (semi-IPN), and interpenetrating polymeric networks (IPN). Exploring the different network types that a hydrogel can form is a way to improve its characteristics regarding mechanical properties, temperature stability, morphological structure, stimuli-responsive behavior, and swelling and release kinetics of active compounds incorporated in it. The intricate nature of interactions within cellulose hydrogels poses a challenge to grasping the nuanced differences in strategies employed to create each unique network. Therefore, this manuscript elucidates the differences between the main types of networks that can be created in cellulose hydrogels, their synthesis methods, benefits, and limitations, serving as a valuable resource to guide future research about cellulose-based hydrogels.

Water Treatment Sludge (WTS) is a solid residue generated in large volumes. This material (in raw or modified form) was never evaluated for endocrine disruptors removal. Thus, the novelty of this work is to evaluate the removal of 17β Estradiol (E2) and 17α Ethinylestradiol (EE2) using adsorbents manufactured from WTS. The WTS underwent heat treatment, resulting in the Physically Modified Sludge (PMS). Then, PMS was chemically activated, giving rise to the sludge activated with phosphoric acid (PAS) or with potassium hydroxide (PHS). The adsorbents were characterized by TGA, ASAP, SEM, FTIR, XRD, XRF, and pH-PZC. The adsorption process was evaluated regarding the adsorbent dosage, kinetic, and isotherms. The modifications imposed on WTS were effective, increasing 1.6 times the surface area and pore volume. The adsorbents presented silica, quartz, and kaolinite in their compositions, and a pH-PZC around 6. The conditions that favor the removal of both endocrine disruptors were: 0.5 g of adsorbent, 100 μg.L−1of initial concentration, pH of 5.5, and 240 min of stirring. PHS was the most promising adsorbent for E2 (with an adsorption capacity of 10.86 μg.g−1) and PMS for EE2 (removing 6.48 μg.g−1of contaminant). The equilibrium time and fits kinetic models varied in function of the adsorbate concentration. The interaction between adsorbents-adsorbates occurs by chemisorption at the active sites and similar fits to Langmuir and Freundlich isotherm models were obtained. From the results obtained, a promising application for WTS residues and an alternative for E2 and EE2 removal from the aqueous solution was proposed.