Abstract
Enroflaxacin (EFX) is one of the most frequently used broad-spectrum synthetic quinolones veterinary drugs and its concentration ranges from 0.3 to 142mg/kg in manure. The misuse/ overuse of antibiotics release residues in various environment, such as soil, agricultural farms, waste water treatment plants, lakes, rivers and ground water. Samples were collected from the veterinary hospital of Valsad district and Pardi (drug affected area). Isolation was performed using Thiosulfate citrate bile salts sucrose medium and Sabourauds medium, 12 isolates of bacteria (YS-1, GM-1, BS, YM, YNL, YS-2, GM-2, GNS, G-1, G-2, GNL and OS) and 3 isolates of fungi (FY, FB, FG) were obtained. These isolates were exposed to three different concentration (5,25,70mmol) of 50 and 150 mg of EFX each to check their tolerance. From which 11 isolates of bacteria were susceptible and 1 isolated bacteria(YM-1) and 3 fungi(FG, FB, FY) were resistant. Field test was performed to check the effect of higher concentration of EFX on isolate YM-1 and all three fungi in soil collected from drug affected area which are able to tolerate the known amount of EFX in bioassay. After 4 days at 200 mmol concentration of EFX no growth of bacteria was observed by SPC but all the three fungi are able to tolerate this concentration of EFX. As no growth was observed in field test at 200mmole concentration, this concentration was exposed to Physical and Biological degradation. Physical degradation was performed using Ultraviolet rays at different interval of time from 1min,…,21min and the smallest zone size of 38mm with strain GM-1 was observed at 21minutes, which shows degradation of EFX after 21 minutes of exposure. Biological degradation of EFX was performed using all 3 isolated fungi in Sabourauds medium and consideration amount of breakdown of EFX was obtain using chemical oxygen demand(COD) colorimetric method. The fungi FB was able to degrade more amount of EFX after exposure for 15 days. OD was measured at 420nm at an interval of 5 days. TLC was performed to check the degraded EFX and the Rf value of degraded EFX was 0.05 and that of standard EFX was 0.7. The fungi FB which can degrade higher amount of EFX in biological method, was identified to be related to Aspergillus niger DTO 370-I7 by molecular identification.