Assessment of Genotoxicity of Zinc Oxide Nanoparticles Using Mosquito as Test Model.

The widespread applications of ZnO NPs in the different areas of science, technology, medicine, agriculture, and commercial products have led to increased chances of their release into the environment. This created a growing public concern about the toxicological and environmental effects of the nanoparticles. The impact of these NPs on the genetic materials of living organisms is documented in some cultured cells and plants, but there are only a few studies regarding this aspect in animals. In view of this, the present work regarding the assessment of the genotoxicity of zinc oxide nanoparticles using the mosquito Culex quinquefaciatus has been taken up. Statistically significant chromosomal aberrations over the control are recorded after the exposure of the fourth instar larvae to a dose of less than LD20 for 24 h. In order to select this dose, LD20 of ZnO NPs for the mosquito is determined by Probit analysis. Lacto-aceto-orcein stained chromosomal preparations are made from gonads of adult treated and control mosquitoes. Both structural aberrations, such as chromosomal breaks, fragments, translocations, and terminal fusions, resulting in the formation of rings and clumped chromosomes, and numerical ones, including hypo- and hyper-aneuploidy at metaphases, bridges, and laggards at the anaphase stage are observed. The percentage frequency of abnormalities in the shape of sperm heads is also found to be statistically significant over the controls. Besides this, zinc oxide nanoparticles are also found to affect the reproductive potential and embryo development as egg rafts obtained from the genetic crosses of ZnO nanoparticle-treated virgin females and normal males are small in size with a far smaller number of eggs per raft. The percentage frequencies of dominant lethal mutations indicated by the frequency of unhatched eggs are also statistically significant (p < 0.05) over the control. The induction of abnormalities in all of the three short-term assays studied during the present piece of work indicates the genotoxic potential of ZnO NPs, which cannot be labeled absolutely safe, and this study pinpoints the need to develop strategies for the protection of the environment and living organisms thriving in it.

An alternative approach towards nitrification and bioremediation of wastewater from aquaponics using biofilm-based bioreactors: A review.

Aquaponics combines the advantages of aquaculture and hydroponics as it suits the urban environment where a lack of agricultural land and water resources is observed. It is an ecologically sound system that completely reuses its system waste as plant fertilizer. It offers sustainable water savings, making it a supreme technology for food production. The two major processes that hold the system together are nitrification and denitrification. The remains of fish in form of ammonia reach the bio filters where it is converted into nitrite and further into nitrate in presence of nitrifying and denitrifying bacteria. Nitrate eventually is taken up by the plants. However, even after the uptake from the flow stream, the effluent contains remaining ammonium and nitrates, which cannot be directly released into the environment. In this review it is suggested how integrating the biofilm-based bioreactors in addition to aquaculture and hydroponics eliminates the possibility of remains of total ammonia nitrogen [TAN] contents, leading to bioremediation of effluent water from the system. Effluent water after releasing from a bioreactor can be reused in an aquaculture system, conditions provided in these bioreactors promote the growth of required bacteria and encourages the mutual development of plants and fishes and eventually leading to bioremediation of wastewater from aquaponics.

The eco-friendly approach of cocktail enzyme in agricultural waste treatment: A comprehensive review.

Agricultural development over the past decade has majorly contributed to the world's bioeconomy, but is the rise in agricultural activities just resulting in the best? Farming, food processing, livestock handling and other agro-based actions show an incremental rise in environmental deterioration by generating millions of tonnes of organic and inorganic solid waste across the globe. Incautious waste handling practices (incineration and landfilling) is resulting in greenhouse gas emissions, land pollution, groundwater contamination, soil erosion and chronic health hazards. Lately the concept of bioconversion has gained importance in valorising agro-waste (lignocellulosic biomasses) into value added products like biofuels, biogas, single cell proteins and biochar to effectively control waste and reduce the dependency on non-renewable feedstocks (fossil fuels). Biomass hydrolysis via enzymes is improved in terms of cost, efficiency, catalysis, stability and specificity by enrolling the use of enzyme cocktails to synergistically degrade lignocellulose into monomeric sugars and further into valued products. Enzyme blends like that of Xylanase + Pectinase + Cellulase shows 76.5% fermentation within 30 h by using banana peel as substrate for biofuel production. Other sectors like paper industries have also explored the use of enzyme blends of Xylanase + Pectinase + α-amylase + Protease+ lipase for bio-bleaching showing reduction in 50% chemical usage and 19.5% kappa number with adjacent increase in tensile strength by 23.55%. The scope of the present review is to highlight the technicalities of the concepts mentioned above, include qualitative data from different relatable studies and prove how the use of enzyme cocktails is an eco-friendly approach towards agro-waste management.