Kinetic Study of the Biodegradation of Acephate by Indigenous Soil Bacterial Isolates in the Presence of Humic Acid and Metal Ions

Abstract

Many bacteria have the potential to use specific pesticides as a source of carbon, phosphorous, nitrogen and sulphur. Acephate degradation by microbes is considered to be a safe and effective method. The overall aim of the present study was to identify acephate biodegrading microorganisms and to investigate the degradation rates of acephate under the stress of humic acid and most common metal ions Fe(III) and copper Cu(II). Pseudomonas azotoformanss strain ACP1, Pseudomonas aeruginosa strain ACP2, and Pseudomonas putida ACP3 were isolated from acephate contaminated soils. Acephate of concentration 100 ppm was incubated with separate strain inoculums and periodic samples were drawn for UV—visible, FTIR (Fourier-transform infrared spectroscopy) and MS (Mass Spectrometry) analysis. Methamidophos, S-methyl O-hydrogen phosphorothioamidate, phosphenothioic S-acid, and phosphenamide were the major metabolites formed during the degradation of acephate. The rate of degradation was applied using pseudo-first-order kinetics to calculate the half-life (t1/2) values, which were 14.33–16.72 d−1 (strain(s) + acephate), 18.81–21.50 d−1 (strain(s) + acephate + Cu(II)), 20.06 –23.15 d−1 (strain(s) + acephate + Fe(II)), and 15.05–17.70 d−1 (strains + acephate + HA). The biodegradation efficiency of the three bacterial strains can be ordered as P. aeruginosa > P. putida > P. azotoformans. The present study illustrated the decomposition mechanism of acephate under different conditions, and the same may be applied to the removal of other xenobiotic compounds.

Interactions between Humic Substances and Microorganisms and Their Implications for Nature-like Bioremediation Technologies

“…Reductive biodegradation mediated by HSs can arguably be effective not only in water but also in solid substrates where anoxic conditions can be found, such as paddy soils [ 228 ]. Instead, most studies showing facilitated biodegradation of organic pollutants after HS amendment explained the observed effect either by mitigating the activity of HSs on bacteria in the presence of a toxicant [ 85 , 230 , 231 ] or by increasing its bioavailability [ 19 , 21 , 51 ]. Another promising area for HS application to reduce soil contamination is an enzymatic transformation and covalent binding of organic pollutants to HSs (oxidative coupling).…”

Biodegradation of phorate by bacterial strains in the presence of humic acid and metal ions

“…At different time intervals, the relative growth of the isolates was checked at 600 nm using a double beam UV-VIS 1800 spectrophotometer (Shimadzu India Ltd.). After, this the degradation of phorate was determined using 250 mg/L of phorate with supplementation of metal ions and humic acid (HA) concentrations [2,17]. An uninoculated medium with 250 mg/L phorate was included as a control sample.…”

COVID-19: Environment concern and impact of Indian medicinal system

“…There are few well-known approaches to clean the environmental compartments including waste management [ [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] , [24] , [25] ]. Techniques like nitrifying-enriched activated sludge (NAS) approach [ [26] , [27] , [28] , [29] , [30] ], microorganisms based approach [ [31] , [32] , [33] ] and conventional activated sludge (CAS) approaches [ 27 , 27 , 28 , 29 , 30 ] are most effective to clean the environment.…”