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Following the circular bioeconomy concept, this work studies the potential of an industrial wastepaper residue as an alternative raw material for dissolving pulp‐grade production. Prehydrolysis‐kraft cooking (PHK), elemental chlorine‐free (ECF) bleaching, and acid‐washing treatments were applied to achieve that aim. Considering the high lignin and hemicellulose content of the raw material, it was submitted to PHK pulping to enhance its cellulose content by removing those components. This processing resulted in a remarkable increase of 84 % in pulp Fock reactivity (from 45.6 % to 84.1 %). The dissolution extension and time in solvent systems LiCl/DMAc and NMMO/H2O were discussed regarding the pulp physicochemical properties. The dissolving pulp produced under this work showed great potential as raw material for textile applications, particularly highlighting the innovative process developed to improve its solubility. [ABSTRACT FROM AUTHOR]

The optimization of wastewater treatment technologies using biological processes is no longer limited to improving the removal of organic matter and nutrients, as it is possible to reduce area and energy consumption, and recover value-added by-products. In this context, the microalgae–bacteria consortium is an alternative for reducing costs, as microalgae produce the oxygen required by bacteria to oxidize organic matter through photosynthesis. Additionally, it is possible to extract different by-products such as lipids, biofertilizers, biogas, alginate-type exopolymers, and others. Furthermore, bioflocculation occurs naturally through the adhesion of microalgae to the surface of bacterial flocs, without the addition of chemical products. This review discusses the main systems that utilize the microalgae–bacteria consortium, the metabolism of the microalgae–bacteria consortium, and its performance in removing organic matter and nutrients, as well as the effect of operating conditions on the physical properties of the biomass. Among the highlighted systems are sequencing batch and single-batch reactors, high-rate ponds, and continuous flow reactors. Among the systems discussed in this work, the sequential batch reactor configurations found better biomass formation and production of extracellular polymeric substances and the continuous flow reactors showed lower installation and operating costs. From this perspective, the potential for full-scale application of each system can be evaluated once the optimum operating conditions have been defined and the limitations of each system have been understood. [ABSTRACT FROM AUTHOR]

The impregnability of Portuguese maritime pine (Pinus pinaster Ait.) subjected to microwave (MW) drying was tested, and the hydrophobicity, anti-swelling efficiency (ASE), and water repellence efficiency (WRE) were evaluated. Small wood heartwood samples of Portuguese maritime pine and two distinct MW treatment settings were employed. The levels of ASE and WRE of the wood elements were evaluated throughout four cycles of drying in an oven and soaking in water. Because of MW applied energy, the wood pine samples were satisfactorily impregnated with the preservative product. Regarding the absolutely dry densities of the samples, very subtle reductions were measured, and they were statistically equivalent to the average density of the non-MW-treated group. Slight improvements were identified in the WRE values of wood samples dried in the microwave. In terms of ASE, both MW-treated groups had a statistically significant increase. The MW treatment decreased the volumetric swelling of the maritime pine wood specimens. Hence, this study raises new insights and previously unexplored paths that can contribute to the expansion and greater application of MW technology in maritime pine and other species. [ABSTRACT FROM AUTHOR]

Microwave (MW) drying of wood has gained popularity in the field of wood modification. The rise in temperature during MW drying leads to increased steam pressure, enhancing wood permeability but potentially decreasing mechanical properties. Understanding temperature and moisture behaviors during MW drying is crucial for its industrial application in wood drying. Therefore, this study aimed to characterize the temperature and moisture behaviors during MW drying of small Portuguese maritime pine (Pinus pinaster Aiton.) wood samples to support a wider use of this technology. The effects on water uptake and the compressive strength parallel to the grain were also investigated. The results indicated three distinct phases in the MW drying rates, with an average of 0.085% of water removed per second. Moreover, the temperature underwent three distinct stages: an initial rapid increase, a period of constant temperature, and a slight decrease until drying was complete. At the beginning of MW drying, the temperatures were below 100 °C, with average temperatures ranging from 126 to 145 °C. Specimens with lower initial moisture content had higher temperatures, and a positive correlation was found between initial moisture content and drying time. In contrast, negative correlations were found between the initial moisture content and average temperature, as well as average temperature and MW drying time. Additionally, the operating condition parameters used in MW drying of pine samples enhanced water impregnability by 65%, generating a slight reduction of 11% in compressive strength. It was also noticed that the initial moisture content did not impact MW-dried samples' water uptake or compressive strength. Finally, although small clear wood samples of maritime pine were utilized, the temperature and moisture patterns observed closely matched real-scale specimens. Thus, the findings corroborate a wide utilization of MW technology for wood drying, mainly demonstrating positive possibilities for structural-sized wood specimens. [ABSTRACT FROM AUTHOR]

BACKGROUND: Chlorella vulgaris is being explored for several applications such as biodiesel production, nutrient supplementation, animal feed and pharmaceutical products. In this study, the performance of a batch culture under progressive light intensity and the effect of hydrogen peroxide (H2O2) concentration on lipid accumulation were investigated. RESULTS: Under progressive light intensity (60 to 300 μmol m−2 s−1), a 43% biomass increase was achieved in comparison with the control light conditions (60 μmol m−2 s−1), whereas a 300 μmol m−2 s−1 light intensity caused growth inhibition to the culture. In addition, an increase in carotenoid content from 0.102 mg g−1 biomass (control) to 0.460 mg g−1 (progressive light) and lipid accumulation from 31.0 mg g−1 (control) to 36.5 mg g−1 (progressive light) was observed. However, the moderate illumination conditions (60 μmol m−2 s−1) induced a very significant increase of chlorophyll b, regarding the progressive light mode, increasing the photosynthetic efficiency. After the growth phase, the biomass was subjected to stress conditions by adding H2O2 to the culture medium at different concentrations: 0.75 mmol L−1 increased the lipid content of the biomass from 3.6% to 10.3% in a 3‐day test, reaching lipid productivity of 70.4 mg L−1 day−1, an increase of ≈40% compared to the phosphate starvatiod for the same culture time. CONCLUSION: The progressive light system allowed an increase in biomass and lipid accumulation. Together with the exposure to H2O2, this work provides a new approach for lipid and pigment production from microalgae. © 2022 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]