Algal-Based Remediation of Synthetic Dyes: A Mini Review

Received 01 Jan, 2025

Accepted 12 Feb, 2025

Published 31 Mar, 2025

A wide variety of algal species have been employed in the breakdown and removal of synthetic dyes from the environment. This paper reviews the various algal species having the potential to remediate synthetic dyes based on published literature. Algae mostly employ the following processes, bioaccumulation, biodegradation, biosorption and photodegradation for dye removal. The notable species of algae that have been employed in the remediation of dyes are Ulva lactuca, Gracilaria, Sargassum, Laminaria, Fucus vesiculosus (macroalgae), Chlorella vulgaris and Spirogyra (microalgae). These species aid in the regulation of contamination in the environment through accumulating and metabolizing the dyes into less harmful substances.

INTRODUCTION

Synthetic dyes are compounds with complex xenobiotic characteristics and chemical structures that are highly resistant to degradation. They exist in different forms and are employed in industrial sectors like textile, tannery, cosmetics and food among others¹. Dyes enter the environment due to several anthropogenic human activities, which is leading to serious irreversible ecological damage, thus, affecting human health and other biological systems², Concerning the aforementioned reasons, the neutralization of these dyes tends to be of great concern, as it will aid in a significant decrease in environmental contamination^3,4. The employment of biological methods to neutralize dyes such as the use of living cells like in algae is very vital^5,6.

Algae-based remediation (phycoremediation) has emerged as an eco-friendly, cost-effective and sustainable alternative for dye degradation and adsorption. Algae possess unique abilities to uptake, degrade, or transform toxic dyes using their metabolic pathways⁷. Additionally, they contribute to oxygen production and nutrient cycling, making them a promising tool for integrated wastewater treatment. Exploring the potential of algal species in dye remediation can help develop efficient bioremediation strategies and contribute to sustainable wastewater management^7,8. Some of the important gaps that have not yet been documented are the detailed metabolic pathways involved in dye breakdown by the algal species, application on large-scale industrial wastewater treatment, strain-specific efficiency and as well, the impact of dye mixtures^9,10.

Phycoremediation involves the complete elimination or biotransformation of environmental pollutants by algal species^11-15. According to Rao et al.¹⁶ phycoremediation is the involvement of certain algal species in the removal or isolation and storage of toxic and non-toxic substances from different forms of waste, which is achieved through metabolic uptake, accumulation, or biotransformation⁵. It is nature-friendly, relatively cheap, generate limited odour and as well consumes less energy¹⁷. García et al.¹⁸ referred to phycoremediation as a safe technology that employs non-pathogenic, photosynthetic organisms (algae) that possess antagonistic effects that enable them to eliminate excessive bacterial loads in the environment. It is mostly associated with the reclamation of wastewater as most algae dwell in aquatic environments. The quality of wastewater undergoing algal treatment determines the algal sludge toxicity which is usually treated before disposal^2,5. The by-product of algal remediation can be transformed into useful components like aquatic feed or growth promoters in plants¹⁹. Moreover, certain algal species exhibit specialized abilities to convert toxic substances to unstable less harmful variants²⁰. Algal mineralization of synthetic compounds is mainly achieved via the trapping and conversion of solar radiation to energy¹⁶. However, there are some limitations associated with the use of algae for remediation, for example, the high toxicity of some dyes may inhibit algal growth, deterring their remediation efficiency. Fluctuations in factors such as pH, illumination, temperature, nutrients, salinity, dye concentration, quantity of Biosorbent and agitation may interfere with algal remediation. Also, the process of algal remediation relatively takes longer periods to attain significant dye removal^5,17.

Algae are photosynthetic organisms with a simple cellular organization that can withstand extreme environmental factors like heavy metals contamination, increased salt levels, imbalance of nutrients and intense temperatures²¹. Algae are highly effective at removing various contaminants owing to their fast growth, extended cellular surfaces and ability to absorb and metabolize pollutants^22,23. Algal species (both micro and macroalgae) have been reported to metabolize dyes either via biosorption onto their surface or enzymatic degradation^14,24,25. The ability of some algal species to adapt to diverse feeding mechanisms (autotrophic, heterotrophic and mixotrophic) enables them to effectively remediate pollutants such as dyes¹⁶. The rate and extent of dye degradation are influenced by the chemical structure of dyes and algal species involved²⁶.

Algal species from Chlorella and Scenedesmus have been reported with the capability to remediate wastewater from different industrial sources as they often flourish in sewage, have increased growth rates and as well high potential in pollutant removal¹⁶. A study conducted by Yan and Pan²⁶ revealed the potentiality of Chlorella pyrenoidosa, Chlorella vulgaris and Oscillatoria tenuis in the biodegradation and bio decolorization of over 30 azo dyes to basic aromatic amines. Another research by Obaid⁷ reported effective dye removal by the algal species Chroococcous, Chlorococcum, Desmococcus and Cosmarium. This review aims at disclosing how algae remove synthetic dyes using certain mechanisms, which subsequently, provides an alternative for mitigating environmental pollution caused by these dyes.

ALGAL MECHANISMS FOR DYE REMOVAL

Biosorption: Biosorption is a passive mechanism that is associated with the binding of dye molecules (chromophores) to functional groups (like hydroxyl, amino, carboxyl and phosphate groups) on the algal cell walls which is triggered by electrostatic attraction and complexation¹⁷. Nair et al.⁸ reported that algal biosorption may be accomplished via either van der Waals force or electrostatic forces exerted between the dyes and biomass (physisorption) or through the establishment of covalent bonds between biomass and dyes (chemisorption). The kind and characteristics of the functional groups exhibited by algae vary by the species. Algae are recognized for having an extensive cellular surface and high binding affinity that aid them in adsorbing dyes and other pollutants²⁷. The algal cell wall is made up of cellulose along with diverse polysaccharides and proteins, serving as binding sites for different pollutants. Both live and decayed algal biomass have been reported in the effective adsorption of various synthetic dyes^8,28. The live algae utilize these dyes as nutrient sources for growth by transforming them into simpler carbon compounds⁵. The effectiveness of algal biosorption of dyes depends on the optimization of certain parameters which include temperature, pH, light, pollutant levels, competing ions and the biosorbent quantity^28,29.

Several kinds of research have reported various algal species as natural bio-adsorbents for removing synthetic dyes from industrial wastewater, some of which include Chlorella vulgaris, Codium decorticatum, Chlamydomonas variabilis, Enteromorpha flexuosa, E. intestinalis Spirulina platensis, Spirulina (Arthrospira) species, Ulva lactuca, Spirogyra species, Nannochloropsis oculata, Phormidium species, Pithophora species, Sargassum swartzii and Scenedesmus quadricauda^8,24,27-35.

Bioaccumulation: Bioaccumulation is an active pollutant detoxification process that activates many metabolic activities within algal cells. It is also referred to as the ability of algae to take up pollutants like dyes into their cells for metabolism or storage^5,36. The capability of algae to accumulate contaminants is dependent upon the species, contaminant levels and other environmental factors³⁷. Algae accumulate dyes either by active transport through various transporters or by the process of endocytosis that requires energy. The dyes accumulate as nutrients within the algal cytoplasm with the aid of different transport proteins on the cell surface²⁸. The oxidative stress induced by the accumulated dyes is usually regulated by antioxidant enzymes secreted by the algae⁵. Furthermore, algae can also reduce the toxic impact of dyes by storing them in vacuoles or binding them to various kinds of proteins³⁸. Bioaccumulation of dyes is achieved by certain algal species like Chlorella vulgaris, Cyanobacteria and Sargassum species³⁹.

Biodegradation: Biodegradation is an active process that deals with the conversion or breakdown of dye molecules into less toxic or non-toxic compounds by certain algae with the help of specialized enzymes or cellular metabolites²⁸. This often occurs through enzymatic reactions and involves the activities of novel enzymes like laccases, peroxidases or azoreductases that may sometimes completely neutralize the dye molecules in water and carbon dioxide. In some instances, these enzymes transform the dyes into useful mineral elements through a process called biomineralization^40-42. Interestingly, several algal species have been reported to be effective in dye remediation due to the possession of the azoreductase enzyme. Some of these species include Chlorella vulgaris, Lyngbya lagerheimii, Nostoc linckia, Oscillatoria species, Oscillatoria limnetica, Oscillatoria rubescens, Elakatothrix viridis, Volvox aureus, Haematococcus species, Scenedesmus obliquus, Spirogyra species (CRW1), Cladophora species (PKS33), which degraded dyes like methyl red, orange II, G-Red (FN-3G), basic cationic, basic fuchsin, malachite green MB, safranin, Congo red, reactive blue, reactive black 71, indigo, disperse red 1, direct blue, direct red 31 and acid orange^8,43-48.

Photodegradation: Photodegradation is a process employed by certain algae that is associated with their release of oxygen during photosynthesis which can often speed up the breakdown of dyes in the presence of solar radiation (photocatalytic degradation)⁴⁹. It often involves the initiation of a redox reaction upon the interaction of a photocatalyst (on the algal surface) with the dye molecule when exposed to light which subsequently leads to the creation of oxygen groups (like hydroxyl), superoxide radicals and hydrogen peroxide⁴⁹. This is very vital in the mineralization of synthetic azo dyes from wastewater in the presence of nanoparticles serving as catalysts⁵⁰. During algal photodegradation of dyes, photons are absorbed and intracellularly degraded through the process of photodissociation⁵¹ Sargassum sp. induced with nanoparticles displayed an effective photodegradation of malachite green due to exposure to a visible light source⁵². Lebron et al.⁵³ studied the photocatalytic reduction of methylene blue dye with the dried biomass of two microalgal species (Chlorella pyrenoidosa and Spirulina maxima) and the result revealed an effective color removal.

ALGAL STRAINS EMPLOYED IN THE REMEDIATION OF SYNTHETIC DYES

A wide range of algal species have been reported to have high potential in neutralizing synthetic dyes. Some of these species will be discussed in this section.

Cyanobacteria: Cyanobacteria (blue-green algae) are bacteria characterized by photosynthetic abilities that are important in ecological processes like pollution control. They have been employed in the remediation of various synthetic dyes including species of Aphanocapsa elachista, Phormidium autumnale (UTEX1580), Hydrocoleum oligotrichum, Chroococcus minutus and Gloeocapsa pleurocapsales. Some of the dyes that were mineralized by these species are indigo, disperse orange 2RL, Tracid red B5, reactive yellow 3RN, reactive black NN, methyl red, basic fuchsin, acid orange, amido black 10R and FF sky blue^54-58.

Microalgal species: Microalgae are diverse microscopic, unicellular, photosynthetic, aquatic organisms. They are of great importance as they participate in various ecosystem services such as absorption of excess atmospheric carbon dioxide and pollutant uptake^15,20.

Chlorella species are green microalgae inhabiting freshwater, marine, or brackish ecosystems. They are the most common microalgae used in dye removal and this is due to their great potential in the tolerance of dye polluted environments^7,34,59. Chlorella vulgaris has been reported to possess high efficiency in dye remediation from industrial effluent or wastewater. They have been used in the breakdown of dyes like ethidium bromide, remazol black B, remazol red RR, remazol brilliant blue R, remazol golden yellow RNL, malachite green, reactive red 195, reactive red 198, reactive yellow 176, reactive yellow 3RN, reactive black NN, reactive orange 122, reactive green 19, reactive violet 1, disperse orange 2RL, Tracid red B5, Tectilon yellow 2G, Congo red, brilliant blue R, napthol green B, Brazil wood, orange G and G-red (FN-3G)^32,57,60-63. Other species of Chlorella, C. pyrenoids and C. marina, have also shown a promising potential in dye remediation^45,64,65.

Other important microalgal species that have proven to be very effective removal of a wide range of synthetic dye removal are Spirogyra species, Scenedesmus quadricauda, S. bijugatus, S. officinalis, Elakatothrix viridis, Volvox aureus, Valoria bryopsis, Padina pavonica, Coelastrella species, Acutodesmus obliquus, Microspora species, Anabaena oryzae, Wollea saccata, Chara vulgaris, Enteromorpha intestinalis, Haematococcus pluvialis, Iridaea cordata, Oscillatoria limnetica, Chlamydomonas reinhardtii, Spirulina platensis, S. maxima, Isochrysis galbana, Tetraselmis species, Nannochloropsis species, Dunaliella salina, Desmodesmus species, Desmodesmus subspicatus, Oedogonium subplagiostomum, Laminaria digitata, Bifurcaria bifurcata, Turbinaria conoides, Raphidocelis subcapitata, Chaetophora elegans, Chlorococcum sp., Ulothrix species, Navicula species, Nitzschia perminuta, Chroococcus minutus, Gloeocapsa pleurocapsales, Phormidium ceylanicum, Hydrocoleum oligotrichum, Cosmarium species, Vaucheria species and Phaeodactylum tricornutum^{14,28,39,53,55,66-74}.

Macroalgal species: A quite number of researches have reported the high effectiveness of macroalgal species in dye remediation⁷⁵. Some representatives of the dye degrading macroalgal species are Stoechospermum marginatum, Ulva lactuca, U. fasciata, Sargassum crassifolium, S. dentifolium, S. swartzii, S. glaucescens, S. muticum, S. latifolium, Gracilaria corticata, G. parvispora, Caulerpa racemosa, C. scalpelliformis, Fucus vesiculosus, Nizamuddinia zanardinii and Gelidium corneum which were reported to have remediated dyes like acid orange II, acid black 1, malachite green, crystal violet, methyl orange, methylene blue, eriochrome black T, remazol brilliant blue, sandocryl golden yellow and reactive red C2G^{8,14,53,75-87}.

ALGAL CONSORTIA EMPLOYED IN DYE REMEDIATION

Algal consortia is a co-culture of algal species or hybrid culture of algal and other microbial species like bacteria and fungi that are used for remediation of dye from wastewater or effluents⁸⁸. This strategy has proven to be very sustainable in the remediation of dye-contaminated environments due to their synergistic effects and enhanced capabilities⁸⁹. In a consortium, each of the strains or species may target specific sites on the dye molecules or may utilize the metabolites produced by another strain or species. Although the use of microbial consortia in dye removal has proven to be very effective, there is limited data on the development of algal consortia for dye remediation⁸⁹.

Moghazy et al.⁸¹ used a consortium of Ulva fasciata and Sargassum dentifolium in the complete neutralization of methylene blue dye. Another study, a consortium of Scenedesmus obliquus and Oscillatoria sp. was employed in the effective remediation of reactive orange 122 and reactive red 194⁹⁰. Effective remediation of malachite green was also observed while using an algal consortium of Chlorella, Cosmarium and Euglena species with the application of an artificial neural network (ANN)^14,91,92. Dye wastewater was successfully treated with a consortium of microalgae, Chlorella sorokiniana and a fungus, Aspergillus species⁹³. Some research revealed the effectiveness of mixed cultures of algae and yeast in the degradation of dyes, implying that microbial consortia can also yield beneficial outcomes for decolourization of dyes^8,14. Ayed et al. ⁹⁴ used an algal-bacterial consortium (Pseudomonas putida, Chlorella and Lactobacillus plantarum) for the complete degradation of CI RB 40 reactive azo dye under optimized conditions.

CONCLUSION

Numerous algal species have demonstrated high effectiveness in degrading various synthetic dyes, either individually or in combination. This has significantly contributed to mitigating the environmental impact of these pollutants. Ongoing research continues to explore new algal species capable of dye mineralization, utilizing advanced biotechnological strategies. Consequently, further discoveries in this field are anticipated shortly.

SIGNIFICANCE STATEMENT

This review presents the mechanisms and techniques governing algal remediation of synthetic dyes, focusing on recent advancements. It consolidates knowledge on algal species, their metabolic pathways and interactions with other organisms, while identifying research gaps in optimizing dye degradation and assessing economic feasibility for large-scale use. It also emphasizes the significance of dye pollution mitigation using algal systems. The employment of new and more advanced biotechnological approaches such as genetically engineered microalgae and hybrid treatment systems may optimize the efficiency of dye removal.

REFERENCES

1. Sani, Z.M., 2023. Bacillus species with dye-remediation potential-A mini review. UMYU J. Microbiol. Res., 8: 212-226.
2. Giovanella, P., G.A.L. Vieira, I.V.R. Otero, E.P. Pellizzer, B. de Jesus Fontes and L.D. Sette, 2020. Metal and organic pollutants bioremediation by extremophile microorganisms. J. Hazard. Mater., 382.
3. Khan, A.U., A.N. Khan, Abdul Waris, M. Ilyas and D. Zamel, 2022. Phytoremediation of pollutants from wastewater: A concise review. Open Life Sci., 17: 488-496.
4. Akter, T., A.T. Protity, M. Shaha, M. Al Mamun and Abu Hashem, 2023. The Impact of Textile Dyes on the Environment. In: Nanohybrid Materials for Treatment of Textiles Dyes, Ahmad, A., M. Jawaid, M.N.M. Ibrahim, A.A. Yaqoob and M.B. Alshammari (Eds.), Springer, Singapore, ISBN: 978-981-99-3901-5, pp: 401-431.
5. Shackira, A.M., N.G. Sarath and J.T. Puthur, 2022. Phycoremediation: A means for restoration of water contamination. Environ. Sustainability, 5: 25-38.
6. Panwar, P., P. Mahajan and J. Kaushal, 2023. Microbial bioremediation of Azo dyes: An environmentally sustainable technology. Rem. J. Environ. Cleanup Costs Technol. Tech., 33: 151-165.
7. Obaid, Z.H., 2024. Potential environmental and health risks of textile dyes and mechanisms treatment for environmental safety by algae-based technologies: A review. Mesopotamia Environ. J., 8: 16-31.
8. Nair, V.K., K. Selvaraju, S. Samuchiwal, F. Naaz, A. Malik and P. Ghosh, 2023. Phycoremediation of synthetic dyes laden textile wastewater and recovery of bio-based pigments from residual biomass: An approach towards sustainable wastewater management. Processes, 11.
9. Gayathiri, E., P. Prakash, K. Selvam, M.K. Awasthi and R. Gobinath, et al., 2022. Plant microbe based remediation approaches in dye removal: A review. Bioengineered, 13: 7798-7828.
10. Shindhal, T., P. Rakholiya, S. Varjani, A. Pandey and H.H. Ngo et al., 2021. A critical review on advances in the practices and perspectives for the treatment of dye industry wastewater. Bioengineered, 12: 70-87.
11. Rao, P.H., R.R. Kumar, B.G. Raghavan, V.V. Subramanian and V. Sivasubramanian, 2011. Is phycovolatilization of heavy metals a probable (or possible) physiological phenomenon? An in situ pilot-scale study at a leather-processing chemical industry. Water Environ. Res., 83: 291-297.
12. Abdel-Raouf, N., A.A. Al-Homaidan and I.B.M. Ibraheem, 2012. Microalgae and wastewater treatment. Saudi J. Biol. Sci., 19: 257-275.
13. Thakur, M., S. Bajaal, N. Rana and M.L. Verma, 2020. Microalgal Technology: A Promising Tool for Wastewater Remediation. In: Microbial Technology for Health and Environment, Arora, P.K. (Ed.), Springer, Singapore, ISBN: 978-981-15-2679-4, pp: 25-56.
14. Bhardwaj, D. and N. Bharadvaja, 2021. Phycoremediation of effluents containing dyes and its prospects for value-added products: A review of opportunities. J. Water Process Eng., 41.
15. Yeheyo, H.A., A.M. Ealias, G. George and U. Jagannathan, 2024. Bioremediation potential of microalgae for sustainable soil treatment in India: A comprehensive review on heavy metal and pesticide contaminant removal. J. Environ. Manage., 363.
16. Rao, P.H., R.R. Kumar and N. Mohan, 2019. Phycoremediation: Role of Algae in Waste Management. In: Environmental Contaminants: Ecological Implications and Management, Bharagava, R.N. (Ed.), Springer, Singapore, ISBN: 978-981-13-7904-8, pp: 49-82.
17. Ayele, A., D. Getachew, M. Kamaraj and A. Suresh, 2021. Phycoremediation of synthetic dyes: An effective and eco-friendly algal technology for the dye abatement. J. Chem., 2021.
18. García, J., R. Mujeriego and M. Hernández-Mariné, 2000. High rate algal pond operating strategies for urban wastewater nitrogen removal. J. Appl. Phycol., 12: 331-339.
19. Rao, P., R.R. Kumar, B.G. Raghavan, V.V. Subramanian and V. Sivasubramanian, 2011. Application of phycoremediation technology in the treatment of wastewater from a leather-processing chemical manufacturing facility. Water SA, 37: 7-14.
20. Leong, Y.K. and J.S. Chang, 2020. Bioremediation of heavy metals using microalgae: Recent advances and mechanisms. Bioresour. Technol., 303.
21. Maurya, R., T. Ghosh, C. Paliwal, A. Shrivastav and K. Chokshi et al., 2014. Biosorption of methylene blue by de-oiled algal biomass: Equilibrium, kinetics and artificial neural network modelling. PLoS ONE, 9.
22. Gupta, S.K., F.A. Ansari, A. Shriwastav, N.K. Sahoo, I. Rawat and F. Bux, 2016. Dual role of Chlorella sorokiniana and Scenedesmus obliquus for comprehensive wastewater treatment and biomass production for bio-fuels. J. Cleaner Prod., 115: 255-264.
23. Olguı́n, E.J., 2003. Phycoremediation: Key issues for cost-effective nutrient removal processes. Biotechnol. Adv., 22: 81-91.
24. Sani, Z.M., A.S. Dalhatu, B.S. Adam, K. Mohammed, Y.Y. Muhammad and S. Ibrahim, 2021. Bioremediation of some reactive dyes commonly used in fabric re-dyeing by Chlorella vulgaris. Asian J. Environ. Ecol., 15: 10-19.
25. Daneshvar, N., A. Aleboyeh and A.R. Khataee, 2005. The evaluation of electrical energy per order (E_Eo) for photooxidative decolorization of four textile dye solutions by the kinetic model. Chemosphere, 59: 761-767.
26. Yan, H. and G. Pan, 2004. Increase in biodegradation of dimethyl phthalate by Closterium lunula using inorganic carbon. Chemosphere, 55: 1281-1285.
27. Zohoorian, H., H. Ahmadzadeh, M. Molazadeh, M. Shourian and S. Lyon, 2020. Microalgal Bioremediation of Heavy Metals and Dyes. In: Handbook of Algal Science, Technology and Medicine, Konur, O. (Ed.), Academic Press, Cambridge, Massachusetts, ISBN: 9780128183052, pp: 659-674.
28. Chugh, M. and N. Bharadvaja, 2022. Phycoremediation of dyes: An overview on mechanism, challenges, and prospects. Ecol. Environ. Conserv., 28: 752-757.
29. Ahmad, A., S.H. Mohd-Setapar, C.S. Chuong, A. Khatoon, W.A. Wani, R. Kumar and M. Rafatullah, 2015. Recent advances in new generation dye removal technologies: Novel search for approaches to reprocess wastewater. RSC Adv., 5: 30801-30818.
30. Aksu, Z. and S. Tezer, 2005. Biosorption of reactive dyes on the green alga Chlorella vulgaris. Process Biochem., 40: 1347-1361.
31. Kumar, K.V., V. Ramamurthi and S. Sivanesan, 2006. Biosorption of malachite green, a cationic dye onto Pithophora sp., a fresh water algae. Dyes Pigm., 69: 102-107.
32. El-Kassas, H.Y. and L.A. Mohamed, 2014. Bioremediation of the textile waste effluent by Chlorella vulgaris. Egypt. J. Aquat. Res., 40: 301-308.
33. Sani, Z.M., I. Garba, A.K. Maigari, S.A. Umar, A. Kabir and I. Bala, 2022. Biosorption of crystal violet dye solution by Aspergillus striatus, Bacillus megaterium, Chlorella vulgaris and Fusarium equiseti. Niger. J. Microbiol., 36: 6102-6110.
34. Abreu, A.P., R. Martins and J. Nunes, 2023. Emerging applications of Chlorella sp. and Spirulina (Arthrospira) sp. Bioengineering, 10.
35. Al-Hammadi, M. and M. Güngörmüşler, 2024. New insights into Chlorella vulgaris applications. Biotechnol. Bioeng., 121: 1486-1502.
36. Kumar, L. and N. Bharadvaja, 2020. Microorganisms: A Remedial Source for Dye Pollution. In: Removal of Toxic Pollutants Through Microbiological and Tertiary Treatment, Shah, M.P. (Ed.), Elsevier, Amsterdam, Netherlands, ISBN: 9780128210147, pp: 309-333.
37. Kwarciak-Kozłowska, A., L. Sławik-Dembiczak and B. Bańka, 2014. Phycoremediation of wastewater: Heavy metal and nutrient removal processes. Environ. Prot. Nat. Resour., 25: 51-54.
38. Arunakumara, K.K.I.U. and Z. Xuecheng, 2008. Heavy metal bioaccumulation and toxicity with special reference to microalgae. J. Ocean Univ. China, 7: 60-64.
39. Abdelfattah, A., S.S. Ali, H. Ramadan, E.I. El-Aswar and R. Eltawab et al., 2023. Microalgae-based wastewater treatment: Mechanisms, challenges, recent advances, and future prospects. Environ. Sci. Ecotechnol., 13.
40. Madadi, R., A.A. Pourbabaee, M. Tabatabaei, M.A. Zahed and M.R. Naghavi, 2016. Treatment of petrochemical wastewater by the green algae Chlorella vulgaris. Int. J. Environ. Res., 10: 555-560.
41. Baghour, M., 2019. Algal Degradation of Organic Pollutants. In: Handbook of Ecomaterials, Martínez, L.M.T., O.V. Kharissova and B.I. Kharisov (Eds.), Springer, Cham, Switzerland, ISBN: 978-3-319-68255-6, pp: 565-586.
42. Satya, A.D.M., W.Y. Cheah, S.K. Yazdi, Y.S. Cheng and K.S. Khoo et al., 2023. Progress on microalgae cultivation in wastewater for bioremediation and circular bioeconomy. Environ. Res., 218.
43. El-Sheekh, M.M., M.M. Gharieb and G.W. Abou-El-Souod, 2009. Biodegradation of dyes by some green algae and cyanobacteria. Int. Biodeterior. Biodegrad., 63: 609-704.
44. Waqas, R., M. Arshad, H.N. Asghar and M. Asghar, 2015. Optimization of factors for enhanced phycoremediation of reactive blue azo dye. Int. J. Agric. Biol., 17: 803-808.
45. Sinha, S., R. Singh, A.K. Chaurasia and S. Nigam, 2016. Self-sustainable Chlorella pyrenoidosa strain NCIM 2738 based photobioreactor for removal of direct Red-31 dye along with other industrial pollutants to improve the water-quality. J. Hazard. Mater., 306: 386-394.
46. Ishchi, T. and G. Sibi, 2020. Azo dye degradation by Chlorella vulgaris: Optimization and kinetics. Int. J. Biol. Chem., 14: 1-7.
47. Abou-El-Souod, G., R.A. Hamouda and M. El-Sheekh, 2020. Influence of heavy metal as co-contamination on biodegradation of dyes by free and immobilized Scenedesmus obliquus. Desalin. Water Treat., 182: 351-358.
48. Gelebo, G.G., L.H. Tessema, K.T. Kehshin, H.H. Gebremariam and E.T. Gebremikal et al., 2020. Phycoremediation of synthetic dyes in an aqueous solution using an indigenous Oscillatoria sp., from Ethiopia: Phycoremediation of synthetic dyes. Ethiopian J. Sci. Sustainable Dev., 7: 14-20.
49. Chowdhury, A.P., K.S. Anantharaju, K. Keshavamurthy and S.L. Rokhum, 2023. Recent advances in efficient photocatalytic degradation approaches for azo dyes. J. Chem., 2023.
50. Bint E Tahir, A.Z. and I. Zahoor, 2024. Photocatalysis and photodegradation of water: A review of processes and advancements. Int. J. Chem. Biochem. Sci., 25: 404-413.
51. Dubey, S., C.W. Chen, D. Haldar, V.S. Tambat and P. Kumar et al., 2023. Advancement in algal bioremediation for organic, inorganic, and emerging pollutants. Environ. Pollut., 317.
52. Rabie, A.M., M.R. Abukhadra, A.M. Rady, S.A. Ahmed and A. Labena et al., 2020. Instantaneous photocatalytic degradation of malachite green dye under visible light using novel green Co-ZnO/algae composites. Res. Chem. Intermed 46: 1955-1973.
53. Lebron, Y.A.R., V.R. Moreira and L.V. de Souza Santos, 2021. Biosorption of methylene blue and eriochrome black T onto the brown macroalgae Fucus vesiculosus: Equilibrium, kinetics, thermodynamics and optimization. Environ. Technol., 42: 279-297.
54. Parikh, A. and D. Madamwar, 2005. Textile dye decolorization using cyanobacteria. Biotechnol. Lett., 27: 323-326.
55. Abou-El-Souod, G.W. and M.M. El-Sheekh, 2016. Biodegradation of basic fuchsin and methyl red by the blue green algae Hydrocoleum oligotrichum and Oscillatoria limnetic. Environ. Eng. Manage. J., 15: 279-286.
56. Dellamatrice, P.M., M.E. Silva-Stenico, L.A.B. de Moraes, M.F. Fiore and R.T.R. Monteiro, 2017. Degradation of textile dyes by cyanobacteria. Braz. J. Microbiol., 48: 25-31.
57. El-Sheekh, M.M., G.W. Abou-El-Souod and H.A. El Asrag, 2018. Biodegradation of some dyes by the green Alga Chlorella vulgaris and the cyanobacterium Aphanocapsa elachista. Egypt. J. Bot., 58: 311-320.
58. Zhang, H., K. Zhang, M. Gao, Z. An, C. Tang and X. Yan, 2022. Degradation efficiency of the azo dye acid orange 2 and microbial community characteristics in a rotating algal biofilm reactor. J. Water Process Eng., 50.
59. Wu, J.Y., C.H. Lay, M.C. Chiong, K.W. Chew and C.C. Chen et al., 2020. Immobilized Chlorella species mixotrophic cultivation at various textile wastewater concentrations. J. Water Process Eng., 38.
60. Hernández-Zamora, M., E. Cristiani-Urbina, F. Martínez-Jerónimo, H.V. Perales-Vela and T. Ponce-Noyola et al., 2015. Bioremoval of the azo dye Congo Red by the microalga Chlorella vulgaris. Environ. Sci. Pollut. Res., 22: 10811-10823.
61. Abd Ellatif, S., M.M. El-Sheekh and H.H. Senousy, 2021. Role of microalgal ligninolytic enzymes in industrial dye decolorization. Int. J. Phytorem., 23: 41-52.
62. Chin, J.Y., L.M. Chng, S.S. Leong, S.P. Yeap, N.H.M. Yasin and P.Y. Toh, 2020. Removal of synthetic dye by Chlorella vulgaris microalgae as natural adsorbent. Arabian J. Sci. Eng., 45: 7385-7395.
63. Selvan, S.T., B.M. Dakshinamoorthi, R. Chandrasekaran, S. Muthusamy, D. Ramamurthy and S. Balasundaram, 2023. Integrating eco-technological approach for textile dye effluent treatment and carbon dioxide capturing from unicellular microalga Chlorella vulgaris RDS03: A synergistic method. Int. J. Phytorem., 25: 466-482.
64. Pathak, V.V., R. Kothari, A.K. Chopra and D.P. Singh, 2015. Experimental and kinetic studies for phycoremediation and dye removal by Chlorella pyrenoidosa from textile wastewater. J. Environ. Manage., 163: 270-277.
65. da Rosa, A.L.D., E. Carissimi, G.L. Dotto, H. Sander and L.A. Feris, 2018. Biosorption of rhodamine B dye from dyeing stones effluents using the green microalgae Chlorella pyrenoidosa. J. Cleaner Prod., 198: 1302-1310.
66. Brahmbhatt, N.H. and R.T. Jasrai, 2016. The role of algae in bioremediation of textile effluent. Int. J. Eng. Res. Gen. Sci., 4: 443-453.
67. Escudero, L.B., P.N. Smichowski and G.L. Dotto, 2017. Macroalgae of Iridaea cordata as an efficient biosorbent to remove hazardous cationic dyes from aqueous solutions. Water Sci. Technol., 76: 3379-3391.
68. Liu, J.H., L. Zhang, D.C. Zha, L.Q. Chen, X.X. Chen and Z.M. Qi, 2018. Biosorption of malachite green onto Haematococcus pluvialis observed through synchrotron Fourier-transform infrared microspectroscopy. Lett. Appl. Microbiol., 67: 348-353.
69. Ajaz, M., S. Shakeel and Abdul Rehman, 2020. Microbial use for azo dye degradation-A strategy for dye bioremediation. Int. Microbiol., 23: 149-159.
70. Hamouda, R.A., N.E.A. El-Naggar, N.M. Doleib and A.A. Saddiq, 2020. Bioprocessing strategies for cost-effective simultaneous removal of chromium and malachite green by marine alga Enteromorpha intestinalis. Sci. Rep., 10.
71. Mahajan, P. and J. Kaushal, 2020. Phytoremediation of azo dye methyl red by macroalgae Chara vulgaris L.: Kinetic and equilibrium studies. Environ. Sci. Pollut. Res., 27: 26406-26418.
72. Maruthanayagam, A., P. Mani, K. Kaliappan and S. Chinnappan, 2020. In vitro and in silico studies on the removal of methyl orange from aqueous solution using Oedogonium subplagiostomum AP1. Water Air Soil Pollut., 231.
73. Ibrahim, M.R., R.A. Hamouda, A.A. Tayel and M.A. Al-Saman, 2021. Anti-cholesterol and antioxidant activities of independent and combined microalgae aqueous extracts in vitro. Waste Biomass Valorization, 12: 4845-4857.
74. Wang, X., S. Ma and F. Kong, 2024. Microalgae biotechnology: Methods and applications. Bioengineering, 11.
75. Omar, H., A.M. El-Gendy and K. Al-Ahmary, 2018. Bioremoval of toxic dye by using different marine macroalgae. Turk. J. Bot., 42: 15-27.
76. Aravindhan, R., J.R. Rao and B.U. Nair, 2007. Removal of basic yellow dye from aqueous solution by sorption on green alga Caulerpa scalpelliformis. J. Hazard. Mater., 142: 68-76.
77. Daneshvar, E., M. Kousha, M.S. Sohrabi, A. Khataee and A. Converti, 2012. Biosorption of three acid dyes by the brown macroalga Stoechospermum marginatum: Isotherm, kinetic and thermodynamic studies. Chem. Eng. J., 195-196: 297-306.
78. Kousha, M., E. Daneshvar, M.S. Sohrabi, M. Jokar and A. Bhatnagar, 2012. Adsorption of acid orange II dye by raw and chemically modified brown macroalga Stoechospermum marginatum. Chem. Eng. J., 192: 67-76.
79. Jerold, M. and V. Sivasubramanian, 2016. Biosorption of malachite green from aqueous solution using brown marine macro algae Sargassum swartzii. Desalin. Water Treat., 57: 25288-25300.
80. Daneshvar, E., A. Vazirzadeh and A. Bhatnagar, 2019. Biosorption of methylene blue dye onto three different marine macroalgae: Effects of different parameters on isotherm, kinetic and thermodynamic. Iran. J. Sci. Technol. Trans. A: Sci., 43: 2743-2754.
81. Moghazy, R.M., A. Labena and S. Husien, 2019. Eco-friendly complementary biosorption process of methylene blue using micro-sized dried biosorbents of two macro-algal species (Ulva fasciata and Sargassum dentifolium): Full factorial design, equilibrium, and kinetic studies. Int. J. Biol. Macromol., 134: 330-343.
82. López-Miranda, J.L., R. Silva, G.A. Molina, R. Esparza, A.R. Hernandez-Martinez, J. Hernández-Carteño and M. Estévez, 2020. Evaluation of a dynamic bioremediation system for the removal of metal ions and toxic dyes using Sargassum spp. J. Mar. Sci. Eng., 8.
83. Saldarriaga-Hernandez, S., E.F. Nájera-Martínez, M.A. Martínez-Prado and E.M. Melchor-Martínez, 2020. Sargassum-based potential biosorbent to tackle pollution in aqueous ecosystems-An overview. Case Stud. Chem. Environ. Eng., 2.
84. Bonyadi, Z., E. Nasoudari, M. Ameri, V. Ghavami, M. Shams and M. Sillanpää, 2022. Biosorption of malachite green dye over Spirulina platensis mass: Process modeling, factors optimization, kinetic, and isotherm studies. Appl. Water Sci., 12.
85. Nielsen, B.V., S. Maneein, J.D. Anghan, R.M. Anghan, M.M. Al Farid and J.J. Milledge, 2022. Biosorption potential of sargassum for removal of aqueous dye solutions. Appl. Sci., 12.
86. El-Sheekh, M.M., M.A. Deyab, N.I. Hassan and S.E. Abu Ahmed, 2023. Bioremediation of malachite green dye using sodium alginate, Sargassum latifolium extract, and their silver nanoparticles. BMC Chem., 17.
87. Fawzy, M.A., A.S. Aloufi, S.H.A. Hassan, A.H. Alessa, A.A. Alsaigh, M. Koutb and I.R. Abdel-Rahim, 2023. Sustainable use of marine macroalga Sargassum muticum as a biosorbent for hazardous crystal violet dye: Isotherm, kinetic and thermodynamic modeling. Sustainability, 15.
88. Akansha, K., T. Kaur, A. Yadav, D. Kour and A.K. Rai et al., 2023. Microbe-mediated remediation of dyes: Current status and future challenges. J. Appl. Biol. Biotechnol., 11: 1-23.
89. Kusumlata, B. Ambade, A. Kumar and S. Gautam, 2024. Sustainable solutions: Reviewing the future of textile dye contaminant removal with emerging biological treatments. Limnological Rev., 24: 126-149.
90. El-Sheekh, M.M., A.R. El-Shanshoury, G.W. Abou-El-Souod, D.Y. Gharieb and S.M. El Shafay, 2021. Decolorization of dyestuffs by some species of green algae and cyanobacteria and its consortium. Int. J. Environ. Sci. Technol., 18: 3895-3906.
91. Khataee, A.R., M. Zarei and M. Pourhassan, 2010. Bioremediation of malachite green from contaminated water by three microalgae: Neural network modeling. CLEAN Soil Air Water, 38: 96-103.
92. Raval, N.P., P.U. Shah and N.K. Shah, 2017. Malachite green “a cationic dye” and its removal from aqueous solution by adsorption. Appl. Water Sci., 7: 3407-3445.
93. Tang, W., X. Xu, B.C. Ye, P. Cao and A. Ali, 2019. Decolorization and degradation analysis of Disperse Red 3B by a consortium of the fungus Aspergillus sp. XJ-2 and the microalgae Chlorella sorokiniana XJK. RSC Adv., 9: 14558-14566.
94. Ayed, L., N. Ladhari, R. El Mzoughi and K. Chaieb, 2021. Decolorization and phytotoxicity reduction of reactive blue 40 dye in real textile wastewater by active consortium: Anaerobic/aerobic algal-bacterial-probiotic bioreactor. J. Microbiol. Methods, 181.