Microbial communities drive flux of acid orange 7 and crystal violet dyes in water-sediment system.

Unchecked dye effluent discharge poses escalating environmental and economic concerns, especially in developing nations. While dyes are well-recognized water pollutants, the mechanisms of their environmental spread are least understood. Therefore, the present study examines the partitioning of Acid Orange 7 (AO7) and Crystal Violet (CV) dyes using water-sediment microcosms and reports that native microbes significantly affect AO7 decolorization and transfer. Both dyes transition from infused to pristine matrices, reaching equilibrium in a fortnight. While microbes influence CV partitioning, their role in decolorization is minimal, emphasizing their varied impact on the environmental fate of dyes. Metagenomic analyses reveal contrasting microbial composition between control and AO7-infused samples. Control water samples displayed a dominance of Proteobacteria (62%), Firmicutes (24%), and Bacteroidetes (9%). However, AO7 exposure led to Proteobacteria reducing to 57% and Bacteroidetes to 3%, with Firmicutes increasing to 34%. Sediment samples, primarily comprising Firmicutes (47%) and Proteobacteria (39%), shifted post-AO7 exposure: Proteobacteria increased to 53%, and Firmicutes dropped to 38%. At the genus level, water samples dominated by Niveispirillum (34%) declined after AO7 exposure, while Bacillus and Pseudomonas increased. Notably, Serratia and Sphingomonas, known for azo dye degradation, rose post-exposure, hinting at their role in AO7 decolorization. Conversely, sediment samples showed a decrease in the growth of Bacillus and an increase in that of Pseudomonas and Serratia. These findings emphasize the significant role of microbial communities in determining the environmental fate of dyes, providing insights on its environmental implications and management.

Regulation and safety measures for nanotechnology-based agri-products.

There is a wide range of application for nanotechnology in agriculture, including fertilizers, aquaculture, irrigation, water filtration, animal feed, animal vaccines, food processing, and packaging. In recent decades, nanotechnology emerged as a prospective and promising approach for the advancement of Agri-sector such as pest/disease prevention, fertilizers, agrochemicals, biofertilizers, bio-stimulants, post-harvest storage, pheromones-, and nutrient-delivery, and genetic manipulation in plants for crop improvement by using nanomaterial as a carrier system. Exponential increase in global population has enhanced food demand, so to fulfil the demand markets already included nano-based product likewise nano-encapsulated nutrients/agrochemicals, antimicrobial and packaging of food. For the approval of nano-based product, applicants for a marketing approval must show that such novel items can be used safely without endangering the consumer and environment. Several nations throughout the world have been actively looking at whether their regulatory frameworks are suitable for handling nanotechnologies. As a result, many techniques to regulate nano-based products in agriculture, feed, and food have been used. Here, we have contextualized different regulatory measures of several countries for nano-based products in agriculture, from feed to food, including guidance and legislation for safety assessment worldwide.

Application of filamentous phages in environment: A tectonic shift in the science and practice of ecorestoration.

Theories in soil biology, such as plant-microbe interactions and microbial cooperation and antagonism, have guided the practice of ecological restoration (ecorestoration). Below-ground biodiversity (bacteria, fungi, invertebrates, etc.) influences the development of above-ground biodiversity (vegetation structure). The role of rhizosphere bacteria in plant growth has been largely investigated but the role of phages (bacterial viruses) has received a little attention. Below the ground, phages govern the ecology and evolution of microbial communities by affecting genetic diversity, host fitness, population dynamics, community composition, and nutrient cycling. However, few restoration efforts take into account the interactions between bacteria and phages. Unlike other phages, filamentous phages are highly specific, nonlethal, and influence host fitness in several ways, which make them useful as target bacterial inocula. Also, the ease with which filamentous phages can be genetically manipulated to express a desired peptide to track and control pathogens and contaminants makes them useful in biosensing. Based on ecology and biology of filamentous phages, we developed a hypothesis on the application of phages in environment to derive benefits at different levels of biological organization ranging from individual bacteria to ecosystem for ecorestoration. We examined the potential applications of filamentous phages in improving bacterial inocula to restore vegetation and to monitor changes in habitat during ecorestoration and, based on our results, recommend a reorientation of the existing framework of using microbial inocula for such restoration and monitoring. Because bacterial inocula and biomonitoring tools based on filamentous phages are likely to prove useful in developing cost-effective methods of restoring vegetation, we propose that filamentous phages be incorporated into nature-based restoration efforts and that the tripartite relationship between phages, bacteria, and plants be explored further. Possible impacts of filamentous phages on native microflora are discussed and future areas of research are suggested to preclude any potential risks associated with such an approach.

Ecotoxic potential of a presumably non-toxic azo dye.

Microbes have potential to convert non-toxic azo dyes into hazardous products in the environment. However, the role of microbes in biotransforming such presumably non-toxic dyes has not been given proper attention, thereby, questions the environmental safety of such compounds. The present study assessed salinity driven microbial degradation of an unregulated azo dye, Acid orange 7 (AO7), under moderately halophilic conditions of textile effluent. The halophilic microbial consortium from effluent decolorized ~97% AO7 (50-500mgL-1). The consortium efficiently decolorized the dye at different pH (5-8) and salinity (5-18% NaCl). The 16S rRNA sequence analyses confirmed the presence of Halomonas and Escherichia in the consortium. The FTIR and GC-MS analyses suggested microbial consortium degrade AO7 following symmetric and asymmetric cleavage and yield carcinogenic/mutagenic aromatic byproducts viz. aniline, 1-amino-2-naphthol, naphthalene, and phenyldiazene. In contrast to AO7, the biodegraded products caused molecular, cellular and organism level toxicity. The degraded products significantly reduced: radicle length in root elongation assay; shoot length/biomass in plant growth assays; and caused chromosomal abnormalities and reduced mitotic index in Allium cepa bioassay. We demonstrated that under saline conditions of textile effluent, halophilic microbes convert a presumably non-toxic azo dye into hazardous products. The study calls to review the current toxicity classification of azo dyes and develop environmentally sound regulatory policies by incorporating the role of environmental factors in governing dye toxicity, for environmental safety.

Isolation and identification of Bacillus megaterium YB3 from an effluent contaminated site efficiently degrades pyrene.

Industrial effluents contaminated sites may serve as repositories of ecologically adapted efficient pyrene degrading bacteria. In the present study, six bacterial isolates from industrial effluents were purified using serial enrichment technique and their pyrene degrading potential on pyrene supplemented mineral salt medium was assessed. 16S rRNA sequence analysis showed that they belong to four bacterial genera, namely Acinetobacter, Bacillus, Microbacterium, and Ochrobactrum. Among these isolates, Bacillus megaterium YB3 showed considerably good growth and was further evaluated for its pyrene-degrading efficiency. B. megaterium YB3 could degrade 72.44% of 500 mg L(-1) pyrene within 7 days. GC-MS analysis of ethyl acetate extracted fractions detected two relatively less toxic metabolic intermediates of the pyrene degradation pathway. B. megaterium YB3 also tested positive for catechol 1, 2-dioxygenase and aromatic-ring-hydroxylating dioxygenase indole-indigo conversion assays. Considering the ability and efficiency of B. megaterium YB3 to degrade high pyrene content, the strain can be used as a tool to develop bioremediation technologies for the effective biodegradation of pyrene and possibly other PAHs in the environment.