Evaluating the potential of thermo-alkaliphilic microbial consortia for azo dye biodegradation under anaerobic-aerobic conditions: Optimization and microbial diversity analysis

• Published in: Journal of environmental management 2022-12, Vol.323, p.116235-116235, Article 116235
• Main Authors: Tizazu, Samson, Tesfaye, Getaneh, Andualem, Berhanu, Wang, Aijie, Guadie, Awoke
• Format: Article
• Language: English
• Subjects: Consortia; Halotolerant; Reactive red 141; Rift valley; Shala hot spring; Thermo-alkaliphilic
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2022.116235

Wastewaters in textile industry are mainly characterized by higher pH, color, salt and chemical oxygen demand (COD) values, which are environmentally undesirable. Among these textile effluent characteristics, color removal is the most challenging task. In this study, the potential of Rift Valley halotolerant and thermo-alkaliphilic microbial consortia (collected from Shala hot spring located in Ethiopia) for azo dye biodegradation under anaerobic-aerobic conditions were evaluated. Optimization and microbial diversity analysis were done using Reactive Red 141. Under optimum conditions of pH (9), temperature (55 °C), salinity (0.5%), and nutrients, microbial consortia can remove >98% color and 92.7 ± 7.3% COD under anaerobic and aerobic conditions, respectively. In addition, the consortia was capable of decolorizing initial dye concentrations of 100–1000 mg/L, and various dye types including Everzol Blue LX, RY 84, RR 239, RB 198 and RY 700. The 16S rRNA gene sequence results showed that Bacteroidetes (25.3%) > Proteobacteria (21.0%) > Chloroflexi (18.5%) > Halobacterota (6.2%) dominant phyla. Based on the findings, non-color effluent adapted Rift Valley halotolerant and thermo-alkaliphilic bacterial consortia can be a potential candidate for bioremediation of textile and other industries characterized by higher salinity, temperature and pH. [Display omitted] •Various optimum conditions (pH = 9, temperature = 55 °C, salt = 0.5%) were investigated.•Anaerobically, Rift Valley hot spring microbes remove >98% RR 141 dye in 6 h.•Under aerobic culturing condition, the bacterial consortia can remove 92.7 ± 7.3% COD.•Bacteroidota, Proteobacteria and Chloroflexi are the dominant phyla identified.•Halotolerant-thermo-alkliphilic microbes fits for textile effluent treatment.