Biodegradation Using Fungal Isolates

Biodegradation Using Fungal Isolates Dr. Jayanthi Abraham* Anjali.M, Caroline Jessica Solomon, V.Vinothini. Abstract Biodegradation is a sustainable and eco friendly way to clean up contaminated environments. The biological processes harnessed play a major role in the removal of contaminants and they make use of the catabolic versatility of microorganisms to degrade/covert compounds which are toxic and difficult to breakdown. The study was done to determine the biodegradation of profenofos using fungal strains. Two fungal strains were isolated and characterized by 18srRNA sequencing. Minimum inhibitory concentration was checked on the fungal isolates. Growth kinetics was performed using Czpax Dox broth to understand the growth pattern of the fungal isolates in the presence and absence of profenofos. The biodegradation of the pesticide was then performed using the isolates grown on minimal and mineral media. Analytical characterizations of profenofos were also done using HPLC, GCMS, and FTIR. Key words: Profenofos, Gro wth kinetics, Biodegradation, fungal isolates. 1. Introduction Modern agricultural practices include the use of various chemical supplements in the form of pesticides such as fungicides, herbicides, and insecticides which are used to manage different groups of pests to maximize crop yield and to meet the demands for higher supplies of food and other agricultural products for the fast-growing human population. Various  benefits are derived from the use of pesticides, however they also cause a wide array of toxicological and environmental problems and often persist in the environment for long periods of time. Organophosphorus insecticides are one of the most commonly used pesticides in agricultural practices. Out of a large number of organophosphate pesticides, profenofos is the one that is most widely used because of its broad spectrum of activity. Profenofos: O-4-bromo-2-chlorophenyl-O-ethyl S-propyl phosphorothioate (C11H15BrClO3PS, Molecular mass 373.6 g/mol]) is widely used for agricultural purposes in India and some other countries such as Australia, China, Pakistan, Egypt and Korea. [1][2][3][4][5][6].It is classified as moderately hazardous(toxicity class II) pesticide by WHO. Profenofos iw widely used on cotton, to control the tobacco budworm, cotton bollworm, armyworm, cotton aphid, mealy bugs, cotton strainers, whiteflies, spider mites, plant bugs, leafhoppers and flea hoppers ,they are used as effective pesticide for watermelon, Chilli peppers, tomatoes, soya beans . An estimated 85% of all profenofos is used to control lepidopteron species (the worm complex) at varying rates. It is a non systemic insecticide and acaricide which is found to have contact and stomach action. Like any other pesticide its effect on non target organisms is unavoidable and they eventually find their way into the food chain. Morphological, reproductive, enzymatic, hormonal and genotoxic effects exhibited by this pesticide have been reported[2]. Profenofos was found to be highly toxic to different organisms including mammals [8] insects  [9], and [6][11] Profenofos has been found to cause cholinesterase inhibition in humans; it over stimulates the nervous system causing nausea, dizziness, confusion, and at very high exposures, respiratory paralysis and death. It has been found that various bacteria such as Pseudomonas diminuta, Flavobacteria sp , Pseudomonas putida , Burkholderia gladioli [12] Pesudomonas aeruginosa , Staphylococcus aureus and Bacillus subtilis . fungi and actinomycetes [13] are able to degrade these pesticides in the soil. Fungi however have been found to be more efficient in doing so. There are several methods which can be used to degrade pesticides which have accumulated in the environment, these process are Photo catalytic degradation, Ozonation, Oxidative processes, Phytoremediation, photo-fenton reactions and bioremediations (Zenilda et al.). Of all these systems bioremediations is found to be most effective because it brings about complete mineralisation unlike in the case of physicalor chemical treatment. Treatment can be done insitu without having to excavate contaminated soil, thus it becomes extremely cost effective.