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Today, the use of nutrients derived from natural bioactive compounds application in the food, pharmaceutical, and cosmetic industries is on the increase. This paper aimed to evaluate the amino acids profile (essential and non-essential) and pigments composition (chlorophyll a , carotenoids, and phycocyanin) of Arthrospira platensis (a blue-green microalga) cultivation in a flat-plate photobioreactor under various types of light-emitting diodes (red: 620-680 nm, white: 380-780 nm, yellow: 570-600nm, blue: 445-480 nm). The maximum biomass concentration (604.96 mg L -1 ) occurred when the red LED was applied for cultivation, and the minimum biomass concentration (279.39 mg L -1 ) was obtained under blue LED. The sequence of pigments and amino acids concentrations (mg L -1 culture volume ) was approximately in accordance with the biomass productivity. It means the red light produces the maximum concentration of pigments (chlorophyll a : 5.42, carotenoids: 2.92, phycocyanin: 67.54 mg L -1 ) and amino acids (essential amino acids: 110.47, nonessential amino acids: 179.10 mg L -1 ). Nevertheless, when these values were measured in mg per g of dry weight, the utmost contents were observed in microalgal products cultivated under blue LED. These consequences are due to the highest cell productivity and the most extended length of cells that occurred under red and blue LEDs, respectively.

Membrane photobioreactors (MPBRs) have gained significant attention due to their ability to support microalgae activities such as cultivation, harvesting, and production of beneficial products. Despite various efforts to mitigate membrane fouling, a fundamental issue in membrane processes, in these systems, a cost-effective and less energy-consuming method is still needed. This study examines the impact of the cross-sectional area of the riser and the baffle material on membrane fouling in an internal loop airlift MPBR. The use of hydrophilic polyester-polypropylene (PES-PP) baffles proves to be more effective than plexiglass baffles. Specifically, in configurations with d  = 0.7 cm and d  = 1.4 cm, R C / R T decreased by approximately 20% and 13%, respectively, compared to plexiglass baffles. As for the values of R P / R T at a distance of d  = 0.7, nearly a 5% increase was observed, and at a distance of d  = 1.4, an increase of approximately 11% was observed. This is due to the development of the cake layer on the matrix structure of the PES-PP baffles instead of the membrane itself. The most optimal outcomes were reached while working with PES-PP at a distance of 0.7 cm, as it prolonged the membrane fouling time to 46 h.

This study reports the development of a magnetic and pH-responsive nanocarrier for targeted delivery and controlled release of doxorubicin (DOX). A multifunctional magnetic chitosan nanocomposite (FA-PAMAMG2-MCS) was fabricated by grafting poly(amidoamine) dendrimer and folic acid onto the MCS surface for active targeting. DOX was loaded into this core-shell bio-nanocomposite via adsorption. Structural and morphological characterization of the prepared nanomaterials was performed using XRD, FT-IR, VSM, TGA, BET, FE-SEM/EDX, and TEM techniques. Adsorption capacity of the FA-PAMAMG2-MCS was optimized by changing diverse parameters, such as pH, initial drug concentration, temperature, contact time, and adsorbent dosage. The maximum adsorption capacity for DOX was 102.85 mg g -1 at 298 K. The in-vitro drug release curve at pHs 5.6 and 7.4 manifested a faster drug release from the prepared nanocarrier in acidic environments and, conversely, a slower release in neutral environments over 48 h. The release kinetics followed Peppas-Sahlin models, showing non-Fickian behavior. Moreover, the in-vitro cytotoxicity studies against the human breast cancer (MDA-MB 231) cell line demonstrated the remarkable anticancer activity of the DOX@FA-PAMAMG2-MCS and declared its potency for nanomedicine applications. This multifunctional system could overcome limitations of conventional chemotherapeutic agents through pH-triggered drug release, enabling targeted cytotoxicity against cancer cells., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Cyanobacteria are photosynthetic aquatic microorganisms with light and dark photosynthesis reactions. In the present study, the effect of various light spectrums on light and dark reactions in Spirulina platensis was investigated. Chlorophyll a and phycocyanin as light reaction pigments and vitamin B 12 as a product of dark reaction were examined. S. platensis was exposed to four different color LEDs (white, red, blue, and yellow) at a fixed intensity. In light reaction, chlorophyll-a has the highest amount in blue, red, white, and yellow by 61.23, 45.46, 34.85, and 22.55 mg·g -1 , respectively. Those microalgae cultured in the blue color produced the highest amount of Chlorophyll a and c-phycocyanin. For C-phycocyanin, the highest to the lowest amount belong to blue, red, yellow, and white light by 168.6, 102.4, 85.77, and 53.81 mg·g -1 . The amount of vitamin B 12 , from high to low is related to blue, red, white, and yellow light by 68.91, 59.73, 52.56, and 10.2 µg·g -1 . The trend of vitamin B 12 's production was similar to the chlorophyll a . In conclusion, blue color can increase the production of vitamin B 12 while keeping light reaction products at their highest level.

In this study, the effect of two membrane cleaning methods, such as aeration and addition of granular particles in a hybrid membrane photobioreactor (HMPBR) including Spirulina sp. with the concentration of 1.5 g·L -1 was investigated. Three different spargers [i.e., different diameters of orifice ( d o ): 0.5, 1, and 1.5 mm] and granular particles (i.e., three packing ratios of 0.5, 1, and 1.5%) were used. The results showed that with the increase in granular packing ratio, R c / R t decreased significantly. The best result was achieved by combining aeration with an orifice diameter of 1.5 mm and a granular packing ratio of 1.5%, which led to the lowest R c / R t value (0.38), while R c / R t value with a d o of 1.5 mm was 0.68 without particles. In contrast, the ratio of pore blocking resistance to total resistance ( R p / R t ) increased by 4.2% under the combined application of 1.5 mm of orifice diameter and 1.5% of granular packing ratio. The results from protein concentrations in the cake layer showed that as the d o became larger, cake protein concentration decreased by 40%, whereas increasing the granular packing ratio from 0.5 to 1.5% increased protein concentration by 60% in the cake layer.

The wastewater produced in a pulp and paper industry is one of the most polluted industrial wastewaters, and therefore its treatment requires complex processes. One of the simple and feasible processes in pulp and paper wastewater treatment is coagulation and flocculation. Overusing a chemical coagulant can produce a large volume of sludge and increase costs and health concerns. Therefore, the use of natural and plant-based coagulants has been recently attracted the attention of researchers. One of the advantages of using Ocimum basilicum as a coagulant is a reduction in the amount of chemical coagulant required. In this study, the effect of basil mucilage has been investigated as a plant-based coagulant together with alum for treatment of paper recycling wastewater. Response surface methodology (RSM) was used to optimize the process of chemical coagulation based on a central composite rotatable design (CCRD). Quadratic models for colour reduction and TSS removal with coefficients of determination of R 2  > 96 were obtained using the analysis of variance. Under optimal conditions, removal efficiencies of colour and total suspended solids (TSS) were 85% and 82%, respectively.

Treatment of industrial wastewater by electrocoagulation (EC) is one of the most efficient methods to remove pollutants. Paper-recycling wastewater is a complex mixture containing toxic and recalcitrant substances, indicating complexity and difficulty of its treatment. The aim of the present study was to assess the effectiveness of paper-recycling wastewater treatment by EC process using aluminum (Al) and iron (Fe) plate electrodes. Removal of chemical oxygen demand (COD), total suspended solids (TSS), color and ammonia from paper-recycling mill effluent was evaluated at various electrolysis times (10-60 min), voltage (4-13 V) and pH (3.5-11). The optimum process conditions for the maximum removal of COD, TSS, color and ammonia from paper-recycling industry wastewater have been found to be pH value of 7, treatment time of 60 min and voltage of 10 V. Under optimum operating conditions, the removal capacities of COD, TSS, color and ammonia were 79.5%, 83.4%, 98.5% and 85.3%, respectively. It can be concluded that EC could be considered as an effective alternative for treatment of paper-recycling wastewater., Competing Interests: Compliance with ethical standardsThe authors would like to declare that there is no conflict of interest with this research and in the publication.

A novel method was developed to assess the viability of activated sludge present in a biological wastewater treatment process and signify its distinction from respirometric activity. The respirometric activity and viability of activated sludge at high cell density, such as typically encountered in membrane bioreactors, were investigated in batch and fed-batch systems. The method for measuring the viability of activated sludge was based on the sludge permittivity monitored online by a capacitive sensor. Results from permittivity measurement were compared with usual biological activity measurement through oxygen uptake rate determination. The similar downward trend was observed for both measurements. The respirometric activity and permittivity, respectively, reduced to 50% and 68% of initial value in the fed-batch system and 18% and 27% of initial value for the batch system which was due to quantitative and qualitative changes in the microbial culture in the activated sludge. The novel method allows to made distinction between viable versus dead and inactive versus active microbial cells in the activated sludge system and can be used for better and more efficient control of the biological processes.