The extensive production of petroleum-based synthetic detergents worldwide presents a huge challenge to sustainability and environmental safety. Efforts are being made to find alternatives from the nature. The study tested plant-based surfactants including soapnut from Sapindus mukorossi and Sapindus trifoliatus and soapbark extract from Quillaja saponaria with anionic surfactants (sodium lauryl sulphate and linear alkyl benzene sulphonate) and commercial detergents (powder and liquid) through wastewater quality analysis and toxicity tests on zebrafish (Danio rerio). A wastewater quality index was used to compare the physicochemical properties of laundry wastewater. Wastewater from all the surfactants tested were acceptable, but acute toxicity tests confirmed that soapnuts and anionic surfactants are more toxic than commercial detergents and Quillaja. Aerobic treatment using microbial consortia neutralises saponins three times more efficiently than natural biodegradation, with up to 60 % saponin degradation within 15 - 30 days. Soapnuts are a proven source of natural surfactant, with applications in industry, animal husbandry, and agriculture, and they have the potential to meet the demand for green detergents and net-zero carbon emission goals. For soapnuts to be environmentally acceptable, the wastewater generated from them and their products must be treated with a combination of aerobic degradation, adsorption and filtration until the saponins are adequately removed.

Coir-Nanocellulose (CNC) has been employed for the reinforcement of Poly(vinyl) alcohol (PVA) films which was further incorporated with neem (Azadirachta indica) extract (NE) to impart antimicrobial characteristics. The three films of PVA, PVA-CNC and PVA-CNC-NE were structurally characterised using SEM, FT-IR and XRD, which confirmed physical and chemical interactions between the components of PVA, CNC and NE. Compared to control PVA, the developed composite films showed improved mechanical, optical, thermal and water resistance properties. PVA film had a moisture content of 6.4%, which got reduced to 5.07% for PVA-CNC-NE films. Incorporation of CNC & NE resulted in enhanced water resistance and reduced solubility of the composite films to 12.35%. Better tensile properties were observed for CNC and NE composite films with an increased Young’s modulus of 1246 MPa, which was 310 MPa for control PVA film. The incorporation of NE on to the composite film help develop antimicrobial and antifungal properties which was attributed to the presence of nimbolinin, nimbin and azadirachtin present in neem extract. The antimicrobial studies revealed better performance with Zone of Inhibition (ZoI) of 9 mm for Staphylococcus aureus and 14 mm for Pseudomonas aeruginosa in case of PVA-CNC-NE films. Moving onward, the different studies performed inveterate the development of PVA-CNC-NE bionanocomposite films with enhanced properties to be utilized as effective alternative in the packaging industry, through further research efforts that justifies its practical utility.

The purpose of this work was to characterize and identify the bacteria isolated from highly polluted locations that could potentially be able to withstand extremely toxic heavy metals. The study area selected for bacterial isolation from sediment samples was Kuzhikandam Creek, a tributary of the Periyar River and one of the world's most hazardous hotspots, located in Kochi's Eloor industrial region. Heavy metal analysis of chromium, copper, and lead in sediment samples was performed, and the results showed that the concentrations were greater than permissible limits. Several metal-resistant bacteria were isolated from sediments, which, upon further screening in solid media at different concentrations of chromium, copper, and lead, found three highly resistant species (S1B1, S2B2, and S3B3), one from each site. The phenotypic and biochemical characterization of these bacteria was examined using standard procedures. The ability of these species to generate biofilm was examined using methods like the crystal violet assay (qualitative assessment) and also using the scanning electron microscope. The antibiotic susceptibility of these species was tested with six different antibiotics, which are used in various disease treatments. These isolates, sequenced using the 16S rRNA Sanger dideoxy method, have been identified as Staphylococcus arlettae, Bacillus paramycoides, and Cellulosimicrobium funkei.

Plastic pollution has quadrupled over the past years and has become a global concern due to its direct impact on life forms. The present study analysed whether the plastic debris in aquatic environments could act as the substratum for the antimicrobial-resistant (AMR) bacteria to form biofilm for survival. We have collected various plastic debris (n = 32) from six sites of the Periyar River, the drinking water source for the entire city and one of the most polluted rivers in Kerala (India). The chemical composition of plastics was screened via FTIR analysis and found that they comprised two types, viz., polyethylene and polypropylene. Bacteria isolated from the samples were screened for the AMR characteristics towards eight different classes of antibiotics. All isolates showed 100% resistance towards colistin and obtained the MAR index value of 0.1-0.4 range. Six representative bacterial isolates with high multiple antibiotic resistance (MAR) index were selected and identified by 16sRNA sequencing as Lysinibacillus mangiferihumi, Bacillus pumilus, Bacillus safensis, Bacillus cereus, Bacillus altitudins and Bacillus pumilus. In vitro biofilm formation was experimented on the purchased plastic samples in artificial media and river water using two selected strains, Bacillus pumilus and Bacillus cereus. Significant variations were observed in biofilm growth in different media (P < 0.05) regardless of plastic types (P > 0.05). The extracellular polymeric substances (EPS) and the characteristic holes on the surface morphology were visualized in SEM analysis, thus indicating the conditioning of the plastics by the isolates for biofilm formation.

Chlorpyrifos, one of the most frequent organophosphorus pesticides, has been linked to major health problems and widespread environmental degradation. It is imperative to remove this herbicide from its point source of contamination since the risk of their off-site migration poses a health concern to non-target organisms. The objective of the present study was to investigate the biodegradation of chlorpyrifos 20% emulsifiable concentration (EC) utilizing a consortium of bacteria that had previously been isolated from a pesticide-contaminated site and are chlorpyrifos tolerant (S27I and S28I). Free cells and immobilized cells with chlorpyrifos as the only carbon source were used to analyze the biodegradation. Charcoal-alginate and kaolin-alginate were the immobilization matrices employed in the investigation. By using gas chromatography-mass spectrophotometer analysis, the degradation of chlorpyrifos was investigated. When compared to free cells, immobilized bacterial isolates showed the greatest amount of biodegradation in the investigation. Consortium (C1) among the isolates degraded chlorpyrifos most quickly compared to S27I and S28I. The study also examined the toxicity of chlorpyrifos at doses of 10, 25, 50, 75, and 100 ppm on the green gram seeds' morphological parameters. Increased chlorpyrifos concentrations resulted in appreciable variations in the germination percentage, shoot length, and root length. The green gram germination study was used to evaluate the detoxification of chlorpyrifos following its breakdown.

Human needs have led to the development of various products which are produced in the industries. These industries in turn have become a source of various environmental concerns. As industries release regulated and unregulated contaminants into the water bodies, it has become a serious concern for all living organisms. Various emerging contaminates from industries like pesticides, pharmaceuticals drugs like hormones, antibiotics, dyes, etc., along with byproducts and new complexes contaminate the water bodies. Numerous traditional approaches have been utilized for the treatment of these pollutants; however, these technologies are not efficient in most cases as the contaminants are mixed with complex structures or as new substances. Advanced technologies such as bioreactor techniques, advanced oxidation processes, and so on have been used for the treatment of industrial wastewater and have served as an alternative way for wastewater treatment. Overall, biological treatment techniques based on bioreactors provide a long-term and ecologically useful solution to industrial wastewater contamination. They play an important role in saving water resources and encouraging a greener sustainable future for mankind. The current review outlines the industrial effluents that are released into water bodies, contaminating them, as well as the numerous traditional and novel treatment procedures used for industrial wastewater treatment.

Considering the exclusive environmental conditions and geological characteristics, Indian flora is extensive and rich in medicinal plants. From primeval times, plant parts and their metabolites have been widely explored for various practices including medicinal as well as culinary. The phytochemicals present in these plants are potential reducing agents for the bio-fabrication of these nanoparticles. The non-toxic nature and combination of the plant phytochemicals with precursor ions act as key aspects for synthesized nanoparticles. The present review highlights the potential applications of Inorganic nanoparticles synthesized from 148 traditionally used medicinal plants present in the Indian geographical region. In addition, parameters that influence the green synthesis of Inorganic nanoparticles such as the extraction methods, solvents used for extraction, the concentration of precursor and plant phytochemicals, pH, temperature, reaction time, and characterization techniques of the nanoparticles are discussed. Thus, the review provides information on the research that has been done in the area of green synthesis using Indian medicinal plants.

Large quantities of pesticides have been released into the environment due to the tremendous development of industry and agriculture. These emerging pollutants are a major risk in the present era. Intimate coupling of photocatalysis and biodegradation (ICPB), a novel wastewater treatment approach that combines the benefits of biological treatment and photocatalytic reactions, has shown significant promise as a low-cost, environmentally friendly, and long-term treatment option. The key principle of ICPB is to transform bio-recalcitrant pollutants into biodegradable products by photocatalysing them on the surface of porous carriers. Then they are completely mineralized into carbon dioxide and water by the microbes present in the interior of the carrier. This chapter provides information regarding the fate, behavior, and effects of pesticides, the mechanism of ICPB, photocatalysts, and carriers used in ICPB, and discusses the application of ICPB to deal with organic pollution.

The development of an efficient and robust photocatalyst is of great importance for the effective treatment of toxic pollutants. In this study, novel Ag3PO4 microspheres were decorated on the nanorod embedded flower-like BiOBr designed for the effective photodegradation of methyl orange (MO) and malachite green (MG) dyes. The synthesized particle was characterized to understand the structural and morphological features using HR-TEM, XRD, SEM, PL, ESR, FT-IR, XPS, EIS and N2 adsorption and desorption. The degradation rate constants for MG (0.0132 min-1) were 3.47 and 3.14 times greater than BiOBr and Ag3PO4. Similarly, the rate constants for MO degradation (0.0151 min-1) are 3.87 and 3.97 times greater than BiOBr and Ag3PO4. The effect of initial MG and MO dye concentration, reaction pH, nanocomposite (NC) concentration was investigated. The NC exhibited excellent visible light photodegradation of 99.8% for MO and 93.4% for MG dyes at 180 min and 200 min respectively. A S-scheme heterojunction were proposed as the possible mechanism for the photodegradation of the dyes. The prepared photocatalyst exhibits excellent structural stability and reusability. The toxicity of the intermediates were predicted by the ecotoxicity analysis using ECOSAR software where the end products were less toxic than parent MG and MO. The degradation pathway were elucidated to predict the possible intermediates and to confirm the complete mineralization of the compound using GC-MS analysis. The proposed study can be implemented for practical application for the degradation of organic pollutants present in the water bodies. (c) 2022 Elsevier B.V. All rights reserved.

The wide usage of antibiotics and their improper management have led to the global dissemination of antimicrobial resistance (AMR). An antibiotic-resistant microbe, the biological emerging contaminant, is a major threat in the modern age. This chapter provides baseline information regarding the various sources, pathways, and removal strategies of AMR bacteria. Sewage inputs and improper treatment systems lead to pollution of natural water systems, the most prone ecosystem to antibiotic resistance. The problem comprises challenges to both the health care and environment sectors. The episodes of pandemics and the emergence of new diseases underline the need for continuous monitoring and regional surveillance networks for antimicrobial resistance.

Soapnuts and other saponin-rich plant materials are known for their phytochemistry and pharmacology. After a gap of two decades, there has been a sudden spate in research on soapnuts with experiments on a wide range of applications. The present review compiles these different aspects of research to explore the possibility of creating a circular economy around soapnut. We are looking at the study from the cradle-to-grave approach. Of the twelve soapnut species present globally, this paper focuses on three- Sapindus mukorossi, S. trifoliatus syn laurifolia, and S. emarginatus. The saponin content varies among the three species, making it difficult to ascertain the critical micelle concentration (CMC), an important functional aspect. Recent research in applications includes surfactants in industry, laundry, bioremediation, biopesticide, poultry feed supplement, biodiesel, biochar, and pharmacology. As an alternative to laundry detergent, soapnut works best at CMC. The ecological services of the tree are restricted to terrestrial ecosystems, while the fruit is toxic to aquatic animals. More research is needed to establish the permissible limits for soapnut saponins in wastewater and their biodegradability before soapnuts can be accepted as a biobased surfactant. Nevertheless, research indicates that it will be beneficial to propagate soapnuts as a sustainable supplement to petroleum-based surfactants and fuels. With many by-products from soapnuts, it is possible to attain zero wastage. Propagation techniques, including natural regeneration, selective crop breeding, vegetative propagation, and tissue culture, have been explored to promote high-quality crops. Planting the appropriate variety of soapnuts could provide a sustainable agroforestry crop that is resilient to climate change.

Mikania micrantha, Sphagneticola trilobata and Chromoleana ordata are three important invasive alien plant species. Alien plant species have caused serious damage to natural ecosystems and plantation crops in many parts of the world. Presently their invasion was observed in agriculture land of Kerala also. The successful invasion of these plants depends on their wide eco-physiological tolerance, strong reproductive ability and allelopathic effects. The study mainly focuses to compare these three invasive plants based their inhibitory effects on crop seeds. Bioassay on the allelopathic effects of leaf extract of these invasive plants showed significant inhibition on crop seeds namely Capsicum annuam, Amaranthus sp and Oryza sativa. Phytochemical screening of the aqueous leaf extract revealed the presence of a variety of secondary metabolites such as phenolic, flavonoids, alkaloids and terpenes. Quinone was observed only in the extract of Sphagneticola trilobata. Allelopathic potential of these plants may facilitate their successful invasion.

Periyar river originates from the Sivagiri peaks of Sundaramala in Tamilnadu with a total length about 300kms in which 244kms in Kerala. Periyar river helps in power generation, domestic water supply, irrigation, tourism, industrial production, fisheries etc. River is undergoing eco degradation due to various anthropogenic stresses. Most prominent industries are situated on the banks of Periyar river. Effluents discharged from these chemical factories to Periyar river eventually reaches to Cochin estuary. Detection of toxic heavy metals which are bio accumulative and carcinogenic from various parts of river is alarming. Eloor, the industrial area situated at the banks of Periyar river recorded a higher rate of nervous system disorders, congenital malformations, circulatory and respiratory disorders, and a wide range of other diseases because of the action of toxic pollutants. Pollutants affect the river quality and even pollute the groundwater resources. Industries are ignoring this warning and none of the works is reported regarding the effluent treatment. There is no proper treatment system for these heavy metals which is discharging to the Periyar river by industries. There is an urgent need to develop an efficient, cost effective waste water treatment system to remove heavy metals and other toxic pollutants.

Saponin was extracted from soapnuts of three species found in India- Sapindus mukorossi, Sapindus trifolatus and Sapindus emarginatus. A modified Vanillin Sulphuric Acid Assay was employed to measure saponin content. Aqueous extract of dried soapnut pericarp was prepared by four methods- ultrasonication, ultrasonication using 50% ethanol-water, maceration and boiling. Saponin, being water soluble, does not require reflux or soxhlet extraction using organic solvents. The modified method used 1% aqueous vanillin solution and 65% Sulphuric acid. Full colour development occurred without heating. Results revealed that S. trifoliates has 34% more saponin than Quillaja standard. S. emarginatus and S. mukorossi contain 80% and 78% more sapogenin than S. trifoliatus respectively. There was no statistically significant difference in the yield of the four extraction methods. Boiling hastens filtration of extract. This method is quicker and needs fewer chemicals to assess saponin content in Sapindus spp.