Strategies to enhance biohydrogen production from microalgae: A comprehensive review.

Microalgae represent a promising renewable feedstock for the sustainable production of biohydrogen. Their high growth rates and ability to fix carbon utilizing just sunlight, water, and nutrients make them well-suited for this application. Recent advancements have focused on improving microalgal hydrogen yields and cultivation methods. This review aims to summarize recent developments in microalgal cultivation techniques and genetic engineering strategies for enhanced biohydrogen production. Specific areas of focus include novel microalgal species selection, immobilization methods, integrated hybrid systems, and metabolic engineering. Studies related to microalgal strain selection, cultivation methods, metabolic engineering, and genetic manipulations were compiled and analyzed. Promising microalgal species with high hydrogen production capabilities such as Synechocystis sp., Anabaena variabilis, and Chlamydomonas reinhardtii have been identified. Immobilization techniques like encapsulation in alginate and integration with dark fermentation have led to improved hydrogen yields. Metabolic engineering through modulation of hydrogenase activity and photosynthetic pathways shows potential for enhanced biohydrogen productivity. Considerable progress has been made in developing microalgal systems for biohydrogen. However, challenges around process optimization and scale-up remain. Future work involving metabolic modeling, photobioreactor design, and genetic engineering of electron transfer pathways could help realize the full potential of this renewable technology.

In vitro antibiofilm, antibacterial, antioxidant, and antitumor activities of the brown alga Padina pavonica biomass extract.

The antibiofilm, antibacterial, antioxidant, and anticancer activities of the methanolic extract of Padina pavonica L. were determined. Results deduced that the algal extract had a high biofilm formation inhibitory action done via crystal violet (CV) assay, to 88-99%. The results showed a strong antibacterial against the identified bacteria species. Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, Klebsiella pneumonia, Bacillus subtilis, and the extract had moderate antibacterial activity against Escherichia coli, Pseudomonas fluorescens and Streptococcus agalactiae. The algal extract has a concentration-dependent DPPH radical scavenging activity (84.59%, with IC50 = 170.31 µg/ml). The inhibitory percent of P. pavonica methanolic extract in vitro antiproliferative activity was 1.79-98.25% with IC50 = 15.14 µg/ml against lung carcinoma. Phenols, terpenes, amino acids, alkaloids, flavones, alcohols, and fatty acids were among the metabolites whose biological actions were evaluated. In conclusion, for the first time, P. pavonica methanolic extract exhibited effective antibiofilm, antibacterial, antioxidant, and anticancer activities. .

Synergistic antibacterial effects of Ulva lactuca methanolic extract alone and in combination with different antibiotics on multidrug-resistant Klebsiella pneumoniae isolate.

Various antibiotics are available, including gentamicin, chloramphenicol, ampicillin, amoxicillin, and streptomycin, but they have some restrictions. Many microorganisms are resistant to these medications. A new antimicrobial source must be found or developed to solve this issue. Inhere, extract from seaweeds Ulva lactuca was investigated for its antibacterial activity using a well diffusion assay against Klebsiella pneumoniae, and a promising inhibition zone diameter was recorded to be 14.04 mm. The biochemical structure of the antibacterial compound was determined via GC-MS and FTIR analysis. Also, a micro-dilution assay was used to calculate the minimum concentration that makes inhibition (MIC) to be 1.25 mg/ml from U. extract reliable to prevent the visibility of any bacterial growth, this was followed by examining the antibacterial effect of U. Lactuca methanolic extract alone and the synergetic effect of U. Lactuca methanolic extract in combination with two different antibiotics (gentamicin and chloramphenicol). This was assayed by the agar well diffusion method to achieve promising and strong inhibiting power against K. pneumoniae. It was deduced that the maximum synergism could be achieved by adding 2.5 mg/ml of Ulva methanolic extract to gentamicin (4 µg/ml), and the results were illustrated obviously via transmission electron microscope in which severe morphological deteriorations were experienced by the treated cells. From this study, we can conclude that U. lactucae extract has the power to aid antibiotics in reducing the growth of pathogenic K. pneumoniae.

Antibacterial and anti-corona virus (229E) activity of Nigella sativa oil combined with photodynamic therapy based on methylene blue in wound infection: in vitro and in vivo study.

Microbial skin infections, antibiotic resistance, and poor wound healing are major problems, and new treatments are needed. Our study targeted solving this problem with Nigella sativa (NS) oil and photodynamic therapy based on methylene blue (MB-PDT). Antibacterial activity and minimum inhibitory concentration (MIC) were determined via agar well diffusion assay and broth microdilution, respectively. Transmission electron microscopy (TEM) proved deformations in Staphylococcus aureus ATCC 6538. Gas chromatography-mass spectrometry identified useful compounds that were suggested to be responsible for the potency of the oil. NS oil was tested as an antivirus against low pathogenic coronavirus (229E). Therapies examined, MB-PDT, NS, and MB-PDT + NS oil, to accelerate wound healing. The antibacterial efficacy against S. aureus was promising, with a MIC of 12.5% and TEM showing injured cells treated with NS oil. This oil inhibited 229E virus up to 42.85% and 32.14%. All tested therapies were successful in accelerating wound healing. The most successful was combined therapy (MB-PDT + NS oil), with a faster healing time. The combined therapy (MB-PDT + NS oil) reduced bacterial counts, which may be a key factor in accelerating wound healing. Skin wound histology was investigated; blood hematology and biochemical analysis did not change significantly after the safe combination treatment. A combination treatment could facilitate healing in a simple and inexpensive way in the future. Based on the results of the in vitro and in vivo studies, it was determined that NS oil had antibacterial and anti-corona virus activity when used in conjunction with photodynamic treatment based on methylene blue to treat wound infections.

New investigation of anti-inflammatory activity of Polycladia crinita and biosynthesized selenium nanoparticles: isolation and characterization.

BACKGROUND: Marine macroalgae have gained interest recently, mostly due to their bioactive components. Polycladia crinita is an example of marine macroalgae from the Phaeophyceae class, also known as brown algae. They are characterized by a variety of bioactive compounds with valuable medical applications. The prevalence of such naturally active marine resources has made macroalgae-mediated manufacturing of nanoparticles an appealing strategy. In the present study, we aimed to evaluate the antioxidant and anti-inflammatory features of an aqueous extract of Polycladia crinita and biosynthesized P. crinita selenium nanoparticles (PCSeNPs) via a carrageenan-induced rat paw edema model. The synthesized PCSeNPs were fully characterized by UV-visible spectroscopy, FTIR, XRD, and EDX analyses. RESULTS: FTIR analysis of Polycladia crinita extract showed several sharp absorption peaks at 3435.2, 1423.5, and 876.4 cm-1 which represent O-H, C=O and C=C groups. Moreover, the most frequent functional groups identified in P. crinita aqueous extract that are responsible for producing SeNPs are the -NH2-, -C=O-, and -SH- groups. The EDX spectrum analysis revealed that the high percentages of Se and O, 1.09 ± 0.13 and 36.62 ± 0.60%, respectively, confirmed the formation of SeNPs. The percentages of inhibition of the edema in pretreated groups with doses of 25 and 50 mg/kg, i.p., of PCSeNPs were 62.78% and 77.24%, respectively. Furthermore, the pretreated groups with 25, 50 mg/kg of P. crinita extract displayed a substantial decrease in the MDA levels (P < 0.00, 26.9%, and 51.68% decrease, respectively), indicating potent antioxidant effect. Additionally, the pretreated groups with PCSeNPs significantly suppressed the MDA levels (P < 0.00, 54.77%, and 65.08% decreases, respectively). The results of immune-histochemical staining revealed moderate COX-2 and Il-1ß expressions with scores 2 and 1 in rats pre-treated with 25 and 50 mg/kg of free extract, respectively. Additionally, the rats pre-treated with different doses of PCSeNPs demonstrated weak COX-2 and Il-1ß expressions with score 1 (25 mg/kg) and negative expression with score 0 (50 mg/kg). Both antioxidant and anti-inflammatory effects were dose-dependent. CONCLUSIONS: These distinguishing features imply that this unique alga is a promising anti-inflammatory agent. Further studies are required to investigate its main active ingredients and possible side effects.

Bioadsorption of Fe (II) ions from aqueous solution using Sargassum latifolium aqueous extract and its synthesized silver nanoparticles.

Algal extracts are used in the environmentally safe and economically advantageous biosynthesis of silver nanoparticles, which does not require the use of hazardous chemicals, high temperatures, pressures, or energies. In the current study, we created silver nanoparticles from the extract of the marine brown alga Sargassum latifolium, analyzed them with Transmission Electron Microscopy (TEM), FTIR, and UV-visible spectrophotometers, and used them to show how well they could remove Fe (II) ions from aqueous solutions. UV scan analyses of S. latifolium aqueous extract of silver nanoparticles showed a maximum peak at 450 nm. This peak is considered a characteristic peak for silver nanoparticles. Also, FTIR analysis of S. latifolium aqueous extract revealed various functional groups such as - OH, -NH, -CH, -COOH, CO, and C-C, which are responsible for bioadsorption of Fe (II). TEM also demonstrated that the synthesized nanoparticles were spherical, distinct, and regular, with particles size about 6.03-15.16 nm. S. latifolium aqueous extract silver nanoparticles were more effective than its aqueous extract in removing Fe (II) from an aqueous solution. The removal efficiency of Fe (II) by nanoparticles was 83%, while by the aqueous extract was 69%. The optimal conditions for bioadsorption of Fe (II) were pH 4, contact time 150, and adsorbent dose 0.01 g.

No work has been reported yet for utilization of marine brown algae Sargassum latifolium aqueous extract to synthesize silver nanoparticles and its application of Fe (II) bioadsorption from aqueous solution.

Impact of immobilized algae and its consortium in biodegradation of the textile dyes.

In biological engineering, cell immobilization is a modern technique for immobilizing free cells in a small space. Disintegration and elimination of azo dyes [Reactive Orange 122 (orange 2RL) and Reactive Red 194 (Reactive Red M-2BF)] were investigated by using Chlorococcum sp. and Chlorococcum sp. mixed with Scenedesmus obliquus, respectively. After 7 days of incubation, the maximum decolorization was spotted at 40 ppm for Reactive Orange 122 and 20 ppm for Reactive Red 194 by Chlorococcum sp. and Chlorococcum sp. mixed with S. obliquus, respectively. The findings revealed that the best decolorization activity was found at pH 11 and 25 °C under aeration conditions. BG11 was considered the best medium for azo dye decolorization with a high decolorization percentage. Additionally, different concentrations of nitrogen and phosphorus show the high activity of decolorization of both dyes. Referring to vitamins (thiamin and Ascorbic acid), all studied concentrations showed high decolorization activity with immobilized Chlorococcum sp. mixed with S. obliquus; however, different concentrations (20, 40, and 60 mg/l) of thiamin showed completely decolorization of Reactive Red 194 after 3 days, and 60 mg/l of ascorbic acid showed completely decolorization of Reactive Orange 122 after 5 days of inoculation. FT-IR and GC-Ms analysis for azo dyes after and before treatment with Immobilization of Chlorococcum sp. and Chlorococcum sp. mixed with Scenedesmus obliquus were detected. Novelty statement: The natural carrier algae and its consortium combined with a suitable immobilization technique were considered in this study, which is non-toxic, enhanced their bioremediation potential for dyes, and allowed multiple uses of biocatalysts. The novel use of the immobilization and its consortium of algae on the degradation efficiency of azo dyes and studying the effect of physicochemical conditions on decolorization and degradation of azo dyes. Application of immobilization techniques using microalgae could be excellent bioremediation of wastewaters.

Chemical Composition, Antioxidant, and Antitumor Activity of Fucoidan from the Brown Alga Dictyota dichotoma.

Brown macroalgae are a rich source of fucoidans with many pharmacological uses. This research aimed to isolate and characterize fucoidan from Dictyota dichotoma var. dichotoma (Hudson) J.V. Lamouroux and evaluate in vitro its antioxidant and antitumor potential. The fucoidan yield was 0.057 g/g algal dry wt with a molecular weight of about 48.6 kDa. In terms of fucoidan composition, the sulfate, uronic acid, and protein contents were 83.3 ± 5.20 mg/g fucoidan, 22.5 ± 0.80 mg/g fucoidan, and 26.1 ± 1.70 mg/g fucoidan, respectively. Fucose was the primary sugar component, as were glucose, galactose, mannose, xylose, and glucuronic acid. Fucoidan exhibited strong antioxidant potential that increased by more than 3 times with the increase in concentration from 0.1 to 5.0 mg/mL. Moreover, different concentrations of fucoidan (0.05-1 mg/mL) showed their ability to decrease the viability of Ehrlich ascites carcinoma cells in a time-dependent manner. These findings provided a fast method to obtain an appreciable amount of natural fucoidan with established structural characteristics as a promising compound with pronounced antioxidant and anticancer activity.

Lychaete pellucida as a novel biosorbent for the biodegradation of hazardous azo dyes.

The majority of textile wastes are made up of toxic dyes. Additionally, because these compounds are soluble, wastewater may include significant concentrations. In this work, the green alga Lychaete pellucida is used for the bioremoval of four common azo dyes, Reactive Blue 4 (RB4), Reactive Red 120 (RR120), Reactive Brilliant Yellow 3G (RBY3G), and Reactive Green12 (RG12), with the application of two models of sorption isotherms, Langmuir and Freundlich. The spectrophotometer method was used to identify optimum conditions (temperature, pH, dye concentrations, algal biomass, and contact time) to remove these dyes onto dry freshwater macroalgae. The optimum pH for L. pellucida was 8. The optimum biosorbent amount is 2 g/L. Then, the best-removed dye concentration was 5 mg/L, the optimum contact duration was 120 min, and the optimum temperature was 25 °C. Under optimum conditions, the percent of dye removal was about 95% for all used azo dyes. This is the first report on the use of Lychaete pellucida for the efficient biodegradation of hazardous azo dyes.

Trophic status determination of the Egyptian Eastern Mediterranean Sea based on phytoplankton diversity and their biochemical contents.

The present study attempted to test the applicability of using phytoplankton as a bioindicator for assessing water quality along the Eastern Alexandria coast, Egypt. Eight stations were selected to cover the different characteristics of seawater during the summer 2022. Six algal groups were detected in different ratios: Bacillariophyceae, Cyanophyceae, Dinophyceae, Chlorophyceae, Silicoflagellata, and Euglenophyceae. Phytoplankton abundance was found highest at the Port Said (PS) beach, and the lowest abundance was detected at Ras El Bar (RB) beach. According to the evaluation of phytoplankton abundance, all the studied stations are oligotrophic state except PS was eutrophic. Based on Chl a concentration, the selected stations could be described as good-bad from west to east. The Shannon diversity and Pielou evenness indexes classified the studied stations as being moderate pollution except for PS and RB stations. The existence of organic pollution indicators species like Navicula, Synedra, and Euglena is a warning indication of the declining water quality especially in B and M stations. The biochemical compositions of the collected phytoplankton were spatial fluctuated. Protein and carbohydrates were the dominant macromolecules in the phytoplankton community compared with lipids. These macromolecules are used to assess trophic states whereas the ratio between protein and carbohydrate > 1 represents a healthy coast as observed in some stations. Thus, phytoplankton should be considered a bioindicator within Water Framework Directive monitoring programs for the Mediterranean Sea. For the long-term monitoring of the Mediterranean Sea's ecosystem, it is recommended that the macromolecules of phytoplankton should be determined.

Antitumor immunity and therapeutic properties of marine seaweeds-derived extracts in the treatment of cancer.

Marine seaweeds are important sources of drugs with several pharmacological characteristics. The present study aims to evaluate the antitumor and antitumor immunological potentials of the extracts from the brown alga Padina pavonica and the red alga Jania rubens, inhibiting the Egyptian marine coasts. Hep-G2 cell lines were used for assessment of the antitumor efficacy of Padina pavonica and Jania rubens extracts in vitro, while Ehrlich ascites carcinoma (EAC) cells were applied to gain more antitumor immunity and antitumor insights of P. pavonica and J. rubens extracts in vivo. In vitro antitumor potentials of P. pavonica and J. rubens extracts were analyzed against human liver cancer Hep-G2 cells by MTT and trypan blue exclusion assays. In vivo antitumor immunological potentials of P. pavonica and J. rubens extracts at low, high, and prophylactic doses were analyzed by blood counting and flow cytometry in mice challenged with Ehrlich ascites carcinoma (EAC) cells. In vitro results revealed that P. pavonica and J. rubens extracts caused significant decreases in the number and viability of Hep-G2 cells in a dose-dependent manner as compared to untreated Hep-G2 cells or Cisplatin®-treated Hep-G2 cells. In vivo findings showed that P. pavonica and J. rubens extracts at low, high, and prophylactic doses significantly reduced the number and viability of EAC tumor cells accompanied by increases in EAC apoptosis compared to naïve EAC mouse. Additionally, P. pavonica and J. rubens extracts at low and prophylactic doses remarkably increased both the total WBC count and the relative numbers of lymphocytes and decreased the relative numbers of neutrophils and monocytes. Flow cytometric analysis showed that P. pavonica and J. rubens extracts at the treatment and the prophylactic doses resulted in a significant increase in the phenotypic expressions of CD4+ T, CD8+ T, and CD335 cells compared to naïve EAC mouse. Overall, both extracts P. pavonica and J. rubens possess potential antitumor and antitumor immunological effects with less toxicity, opening new approaches for further studies of the chemical and biological mechanisms behind these effects.

Biological control of Fusarium tomato-wilt disease by cyanobacteria Nostoc spp.

This study investigated the effect of foliar application of extract and culture of Nostoc calcicola and Nostoc linckia on the Fusarium oxysporum f. sp. lycopersici (FOL) that infects tomatoes (Solanum lycopersicum) plant in vitro and in vivo. Cyanobacterial isolates were isolated from saline soils at El-Hamoul and Seidy Salem locations Kafr Elsheikh, Egypt, and identified to be N. calcicola and N. linckia Bioactive compounds of extract were analyzed by Gas chromatography-mass spectrometry (GC-MS). Dry weight, carotene, chlorophyll content, and total phenolic compounds of isolates were measured. Plant height, dry weight, fruit number, and fruit weight of tomatoes were estimated. GC/MS analysis showed 49 and 35 bioactive compounds in extracts of N. calcicola and N. linckia, respectively. N. calcicola possesses the highest values of chlorophyll a, carotenoid, and total phenol contents in dry weight compared with N. linckia. After 100 days of tomato growth, the results showed the highest yield of tomato fruits with the application of N. calcicola and N. linckia compared with the untreated plants and the plants which were infected with Fusarium, suggesting that N. calcicola and N. linckia can serve as a new bioagent for biological control of the soil fungus Fusarium oxysporum f. sp. lycopersici (FOL).

A Review of Microalgae- and Cyanobacteria-Based Biodegradation of Organic Pollutants.

This review proposes a new bioremediation method based on the diverse functionalities of algae. A greenway for cleansing wastewater is more ecologically friendly and environmentally sustainable than prior methods with other bacteria. New bioremediation technology employing algae and cyanobacteria for the removal of a wide range of organic contaminants is reasonable and has great potential. The prevalence of organic contaminants in aquatic habitats may endanger the health and well-being of several marine creatures. Agriculture, industry, and household trash are just a few of the human-caused sources of organic pollutants that contaminate waterways around the world. Before wastewater can be released into waterways, it must be cleaned. Algae-based wastewater treatment systems are becoming increasingly popular because of their environmental sustainability and lack of secondary pollutants. According to the kind of pollutant, the physicochemical properties of wastewater, and the algal species, algae and cyanobacteria can absorb and accumulate a wide spectrum of organic pollutants at different rates. In addition, phytoremediation is a cost-effective alternative to conventional treatments for degrading organic contaminants. Phycoremediationally produced algal biomass may also be an important part of the bioenergy value chain. This article focuses on microalgae and cyanobacteria species, which may remove many organic contaminants from water systems.

Antiviral activity of algae biosynthesized silver and gold nanoparticles against Herps Simplex (HSV-1) virus in vitro using cell-line culture technique.

As therapeutic antiviral agents, biological nanoparticles can fight the drug-resistant types of viruses helping the antiviral drug development. In this study, two blue-green algal strains; Oscillatoria sp. and Spirulina platensis were used, mediated by green Ag2O|AgO-NPs and Au-NPs, respectively. For NPs characterization, the UV/Vis spectroscopy were used where their formation and crystallinity were proven with λmax values for silver and gold NPs of 432 and 552 nm, respectively. The transmission electron microscope (TEM) X-ray diffraction showed a spherical-shaped Ag2O|AgO-NPs (size; 14.42 to 48.97) while Au-NPs appeared with octahedral, pentagonal and triangular structures (size; 15.60-77.13 nm). The reducing, capping, and stabilization activities of algal polysaccharides and proteins were indicated via FTIR spectroscopy. Both Ag2O|AgO-NPs and Au-NPs were investigated against Herpes Simplex virus (HSV-1) that has been indicated by its reduction activity of cytopathic effect (CPE). Cytotoxicity was evaluated on Vero cells and measured by MTT assay. Results showed a 90% reduction in CPE of HSV-1 applying Ag2O|AgO-NPs, and Au-NPs at 31.25 µL., with a high reduction rate (49.23%) with Ag2O|AgO-NPs than that of Au-NPs (42.75%). Current results proved the efficiency of green nanotechnology application with both Ag2O|AgO-NPs, and Au-NPs as reducing and inhibitory agents for the HSV-1 replication.

Role of microalgal ligninolytic enzymes in industrial dye decolorization.

In this study, the decolorization efficiency of seven microalgae isolates; Nostoc muscorum, Nostoc humifusum, Spirulina platensis, Anabaena oryzae, Wollea saccata, Oscillatoria sp. and Chlorella vulgaris was investigated for dye decolorization. The highest decolorization percentages of Brazilwood, Orange G, and Naphthol Green B dyes (99.5%, 99.5%, and 98.5%, respectively) were achieved by Chlorella vulgaris. However, the maximum efficiency for dye decolorization percentages of CV and malachite green dyes were exhibited by A. oryzae (97.4%) and W. saccata (93.3%). Ligninolytic enzymes activity assay was carried out for laccase and lignin peroxidase enzymes, which revealed a high efficiency of the C. vulgaris, A. oryzae and W. saccata to lignin containing compound degradation. The highest laccase production recorded by C. vulgaris with Brazilwood, Orange G, and Naphthol Green B dyes (665.0, 678.6, and 659.5 U/ml, respectively). Similarly, C. vulgaris gave a high lignin peroxidase enzyme production with the above three dyes respectively (306.00, 298.34, and 311.45 U/ml). In addition, A. oryzae and W. saccata showed the highest production of the laccase enzyme (634.6 and 577.45 U/ml, respectively) with CV and malachite green dyes. The degradation products have been characterized after decolorization and verified using FTIR analysis. The high decolorization percentages achieved by C. vulgaris, A. oryzae and W. saccata make them potential candidates for bioremediation and pre-processing to remove dyes from textile effluents.

Green synthesis, characterization applications of iron oxide nanoparticles for antialgal and wastewater bioremediation using three brown algae.

This study aims at controlling excess nutrients, including nitrogen and phosphorus, and harmful algae that pollute the marine environment using biosynthesized iron oxide nanoparticles. Aqueous extracts of brown seaweeds named Petalonia fascia, Colpomenia sinuosa, and Padina pavonica were selected for iron oxide nanoparticles' biosynthesis. The extracts were used as reductants of ferric chloride, and dark brown colors due to Fe3O4-NPs biosynthesis were observed. Iron signals were recorded in EDX spectra. FTIR analyses showed that the three algae extracts contained proteins and lipids that have the ability to proceed dual functions of bioreduction and stabilization of Fe3O4-NPs, suggesting that proteins in P. fascia, C. sinuosa, and P. pavonica extracts reduced FeCl3, and the aromatic compounds stabilized the biogenic Fe3O4-NPs. The biosynthesized Fe3O4-NPs via P. pavonica had the best nitrogen reduction percentage, followed by C. sinuosa and P. fascia for both concentrations 2 and 4 µg mL-1. The best results of phosphorus removal and Chlorophyll a (Chl a) reduction percentages using the Fe3O4-NPs concentrations were 2 and 4 µg mL-1 with nanoparticles synthesized via P. fascia and P. pavonica, respectively. The highest reduction in optical density for both 2 and 4 µg mL-1 was achieved by the nanoparticles synthesized by P. fascia. Novelty StatementApplication of nanoparticles using seaweeds extracts could be alternative safe bioremediation of wastewaters. Currently, iron oxide nanoparticles are used to reduce nitrogen and phosphorus and reduce the blooming of harmful algae; little information about this issue has been reported. Such study also presented the anti-algal impacts of Fe3O4-NPs by tracing optical density and Chl a concentrations in the examined real seawater samples. Modern biotechnology to develop phytoremediation and seaweeds to enhance these remediation methods can be adopted.

Phycological and bacteriological assessment of drinking water in schools of Tanta city, Egypt.

Frequent water analysis is required to discover pollutants, describe water characteristics, and create a database for the water type that must be cleansed and treated in order to generate healthy water and, as a result, determine the best treatment method. In this regard, the goal of this research was to evaluate the overall physicochemical, phycological, and bacteriological properties of tap water samples taken periodically from 12 different Tanta city schools. In total, 57 algal species were identified throughout the investigation, 33 species belonging to Chlorophyta, 13 species to Bacillariophyta, and 11 species to Cyanophyta. Phytoplankton species richness and diversity were relatively stable in each school all year round. Chlorella, Cyclotella, Scenedesmus, which are organically pollution-tolerant genera according to Palmer's pollution index, were observed in the present study. Throughout the research seasons, total and fecal coliform bacteria were positively correlated (r = 0.94) in all of the study area sites. The counts of pollution indicators were more in groundwater than treated water.

Therapeutic Uses of Red Macroalgae.

Red Seaweed "Rhodophyta" are an important group of macroalgae that include approximately 7000 species. They are a rich source of structurally diverse bioactive constituents, including protein, sulfated polysaccharides, pigments, polyunsaturated fatty acids, vitamins, minerals, and phenolic compounds with nutritional, medical, and industrial importance. Polysaccharides are the main components in the cell wall of red algae and represent about 40-50% of the dry weight, which are extensively utilized in industry and pharmaceutical compounds, due to their thickening and gelling properties. The hydrocolloids galactans carrageenans and agars are the main red seaweed cell wall polysaccharides, which had broad-spectrum therapeutic characters. Generally, the chemical contents of seaweed are different according to the algal species, growth stage, environment, and external conditions, e.g., the temperature of the water, light intensity, nutrient concentrations in the ecosystem. Economically, they can be recommended as a substitute source for natural ingredients that contribute to a broad range of bioactivities like cancer therapy, anti-inflammatory agents, and acetylcholinesterase inhibitory. This review touches on the main points of the pharmaceutical applications of red seaweed, as well as the exploitation of their specific compounds and secondary metabolites with vital roles.

Lockdowns and reduction of economic activities during the COVID-19 pandemic improved air quality in Alexandria, Egypt.

Parallel reductions in atmospheric aerosols (particulate matter (PM)) and nitrogen dioxide (NO2) accompanied the drastic measures that were adopted to limit the spread of COVID-19. The results of this preliminary study conducted in northern Egypt revealed that ambient PM10, PM2.5, and NO2 levels decreased by 22.8%, 29.3%, and 25.9%, respectively, after the lockdown started on March 13, 2020. These reductions in concentrations significantly (p ˂ 0.01) correlated with the decrease in transportation and industrial and other economic activities. Furthermore, PM and NO2 concentrations radically reduced during the full lockdown on Easter, Ramadan, and Eid Al-Fitr. The findings of this study will help the World Health Organization (WHO) and other health regulators to combat COVID-19 in the world. This study is part of an ongoing research related to the current pandemic.

Monitoring the degradation capability of novel haloalkaliphilic tributyltin chloride (TBTCl) resistant bacteria from butyltin-polluted site.

Tributyltin (TBT) is recognized as a major environmental problem at a global scale. Haloalkaliphilic tributyltin (TBT)-degrading bacteria may be a key factor in the remediation of TBT polluted sites. In this work, three haloalkaliphilic bacteria strains were isolated from a TBT-contaminated site in the Mediterranean Sea. After analysis of the 16S rRNA gene sequences the isolates were identified as Sphingobium sp. HS1, Stenotrophomonas chelatiphaga HS2 and Rhizobium borbori HS5. The optimal growth conditions for biodegradation of TBT by the three strains were pH 9 and 7% (w/v) salt concentration. S. chelatiphaga HS2 was the most effective TBT degrader and has the ability to transform most TBT into dibutyltin and monobutyltin (DBT and MBT). A gene was amplified from strain HS2 and identified as TBTB-permease-like, that encodes an ArsB-permease. A reverse transcription polymerase chain reaction analysis in the HS2 strain confirmed that the TBTB-permease-like gene contributes to TBT resistance. The three novel haloalkaliphilic TBT degraders have never been reported previously.