Algal and cyanobacterial biomass as potential dye biodecolorizing material: a review

Biosorption of Remazol Brilliant Blue R textile dye using Clostridium beijerinckii by biorefinery approach

The current study proposes RBBR biosorption by Clostridium beijerinckii DSMZ 6422 biomass remaining after biobutanol production from pumpkin peel (PP) by a zero-waste approach. Efficient biobutanol production was achieved by investigating initial PP concentrations (5-20% without or with enzymatic hydrolysis) and fermentation time. According to this, the highest concentrations of biobutanol and total ABE were obtained as 4.87 g/L and 8.13 g/L in the presence of 10% PP without enzymatic hydrolysis at 96 h. Furthermore, based on the zero-waste approach, C. beijerinckii DSMZ 6422 biomass obtained after biofuel production was used as a biosorbent for the removal of RBBR dye. Response surface methodology (RSM), commonly utilized for the experimental design, was used to specify the optimized biosorption conditions of RBBR, including initial dye concentration (50-200 mg/L), initial pH (2-6), biosorbent concentration (1-3 g/L), and contact time (0-240 min). The highest biosorption under optimized conditions with RSM was 98% in the presence of 194.36 mg/L RBBR and 2.65 g/L biosorbent at pH 2 and 15 min. This is the first report in the literature about the biosorption of RBBR dye by anaerobic C. beijerinckii biomass after the biobutanol production process. This study also shows the efficient usage of agricultural and microbial wastes in different areas based on zero-waste applications.

Recent Strategies for the Remediation of Textile Dyes from Wastewater: A Systematic Review

The presence of dye in wastewater causes substantial threats to the environment, and has negative impacts not only on human health but also on the health of other organisms that are part of the ecosystem. Because of the increase in textile manufacturing, the inhabitants of the area, along with other species, are subjected to the potentially hazardous consequences of wastewater discharge from textile and industrial manufacturing. Different types of dyes emanating from textile wastewater have adverse effects on the aquatic environment. Various methods including physical, chemical, and biological strategies are applied in order to reduce the amount of dye pollution in the environment. The development of economical, ecologically acceptable, and efficient strategies for treating dye-containing wastewater is necessary. It has been shown that microbial communities have significant potential for the remediation of hazardous dyes in an environmentally friendly manner. In order to improve the efficacy of dye remediation, numerous cutting-edge strategies, including those based on nanotechnology, microbial biosorbents, bioreactor technology, microbial fuel cells, and genetic engineering, have been utilized. This article addresses the latest developments in physical, chemical, eco-friendly biological and advanced strategies for the efficient mitigation of dye pollution in the environment, along with the related challenges.

Insight into dissolved organic nitrogen transformation and characteristics: Focus on printing and dyeing wastewater treatment process

Textile industry discharges large amounts of printing and dyeing wastewater (PDW) containing high concentration of refractory dissolved organic nitrogen (DON). However, the DON transformation and characteristics during PDW treatment, and its potential environment impact receive little concern. Treatment groups of dyeing wastewater (G-RB5), printing wastewater (G-Urea) and domestic wastewater (G-NH₄Cl) with Reactive Black 5 (RB5), Urea and NH₄Cl as influent nitrogen species were set to compare the DON behavior during the hydrolytic acidification-aerobic-anoxic process. G-RB5 exhibited higher DON concentrations with greater fluctuations, and its effluent dominated low molecular weight (LMW) and hydrophilic DON, showing high bioavailability (67.6%) and low biodegradation (8.0%). In the aerobic section, the concentration of microorganism-derived DON in G-RB5 was higher but the nitrogen species were fewer than G-Urea and G-NH₄Cl. Grey relational analysis revealed that Proteobacteria and Thauera were the common bacteria strains showing high association degree (γ > 0.9) with biodegradable DON (ABDON) in all groups; while microbes related with biodegradable DON (BDON) varied between groups. The higher contents of DON, ABDON, LMW-DON and hydrophilic DON induced by RB5 highlight the importance of controlling DON from textile industry to mitigate the potential risk like algae growth stimulation, which needs more attention in future.

Fungal assisted bio-treatment of environmental pollutants with comprehensive emphasis on noxious heavy metals: Recent updates

In the present time of speedy developments and industrialization, heavy metals are being uncovered in aquatic environment and soil via refining, electroplating, processing, mining, metallurgical activities, dyeing and other several metallic and metal based industrial and synthetic activities. Heavy metals like lead (Pb), mercury (Hg), cadmium (Cd), arsenic (As), Zinc (Zn), Cobalt (Co), Iron (Fe), and many other are considered as seriously noxious and toxic for the aquatic environment, human, and other aquatic lives and have damaging influences. Such heavy metals, which are very tough to be degraded, can be managed by reducing their potential through various processes like removal, precipitation, oxidation-reduction, bio-sorption, recovery, bioaccumulation, bio-mineralization etc. Microbes are known as talented bio-agents for the heavy metals detoxification process and fungi are one of the cherished bio-sources that show noteworthy aptitude of heavy metal sorption and metal tolerance. Thus, the main objective of the authors was to come with a comprehensive review having methodological insights on the novel and recent results in the field of mycoremediation of heavy metals. This review significantly assesses the potential talent of fungi in heavy metal detoxification and thus, in environmental restoration. Many reported works, methodologies and mechanistic sights have been evaluated to explore the fungal-assisted heavy metal remediation. Herein, a compact and effectual discussion on the recent mycoremediation studies of organic pollutants like dyes, petroleum, pesticides, insecticides, herbicides, and pharmaceutical wastes have also been presented.

Lysinibacilli: A Biological Factories Intended for Bio-Insecticidal, Bio-Control, and Bioremediation Activities

Microbes are ubiquitous in the biosphere, and their therapeutic and ecological potential is not much more explored and still needs to be explored more. The bacilli are a heterogeneous group of Gram-negative and Gram-positive bacteria. Lysinibacillus are dominantly found as motile, spore-forming, Gram-positive bacilli belonging to phylum Firmicutes and the family Bacillaceae. Lysinibacillus species initially came into light due to their insecticidal and larvicidal properties. Bacillus thuringiensis, a well-known insecticidal Lysinibacillus, can control many insect vectors, including a malarial vector and another, a Plasmodium vector that transmits infectious microbes in humans. Now its potential in the environment as a piece of green machinery for remediation of heavy metal is used. Moreover, some species of Lysinibacillus have antimicrobial potential due to the bacteriocin, peptide antibiotics, and other therapeutic molecules. Thus, this review will explore the biological disease control abilities, food preservative, therapeutic, plant growth-promoting, bioremediation, and entomopathogenic potentials of the genus Lysinibacillus.

Microbial Degradation of Azo Dyes: Approaches and Prospects for a Hazard-Free Conversion by Microorganisms

Azo dyes have become a staple in various industries, as colors play an important role in consumer choices. However, these dyes pose various health and environmental risks. Although different wastewater treatments are available, the search for more eco-friendly options persists. Bioremediation utilizing microorganisms has been of great interest to researchers and industries, as the transition toward greener solutions has become more in demand through the years. This review tackles the health and environmental repercussions of azo dyes and its metabolites, available biological approaches to eliminate such dyes from the environment with a focus on the use of different microorganisms, enzymes that are involved in the degradation of azo dyes, and recent trends that could be applied for the treatment of azo dyes.