The mineral salt media.
The Bacillus megaterium ability was evaluated in this paper to degrade the Glyphosate. organophosphorus pesticides, The bacteria re-cultured that isolated from other researches of Baghdad soils and morphological identification and biochemical tests besides by selectivity media. The (5 and 25) ppm showed the highest growth results were within two days to two months on mineral salt media. The highest glyphosate degradation ratio % were (70) % per 25 ppm/two months. Incubation period Increasing led to highest glyphosate degradation ratio% at (25) ppm led to conclusion that bacteria digestive the pesticides as carbon and nitrogen sources and will be well harvest it form contaminated areas.
Glyphosate is an organophosphate which is a heterogeneous compound, utilized on the grasses leaves and broadleaf plants due its non-selectivity pesticides. In the seventies was the first registration in the United State by Monsanto (Roundup) . Glyphosate stops a shikimic acid enzyme pathway which is essential for some microorganisms and plants. In trace analysis, Glyphosate is a difficult herbicide, has a good water solubility that causes difficulty in determination its physical and chemical properties .
The microorganism ability to eliminate pollutants is one of the bioremediation methods . Bioremediation is applied as an auxiliary strategy due to its inoffensive to ecology, economic worth, reduce environmental poison, and validation [4, 5, 6, 7, 8]. Metabolic is one of the microorganism degradation methods across pesticides in soils, also catabolism strategies and the enzymes of co-metabolism . Organic-pesticides fate in the ecology system can be marked by utilizing biodegradation as a major agent. The study purpose is to achieve and inspect the domestic bacterial separated on broken down different glyphosate concentrations that can be remaindered in soil and detect residues concentration from bacteria digestive via HPLC after extraction.
2. Material and methods
Chemosate. The trade name of “Glyphosate”, bought from the local market. Materials were available and supply in Remediation Pollutants Center. The Mineral Salt Media (MSM), was used in growing
|0.2||KH2PO4||Sterilized separately at 125 °C/25 min (part A)|
|1||(NH4)2SO4||All mixed and added to part A of 1-liter flask, and adjust (pH 7.0 ± 0.3)|
2.2 Re-growth and identification of
|10||Glucose||1liter distillate water|
adjust (pH 7.0 ± 0.3)
incubate28-30 °C/48 h.
2.3 Glyphosate degradation ratio via
The degradation ratio % investigated for (1-2) months, extracted through added equal volume each ethyl acetate and MSM which utilized as a reagent, for twice time, centrifuged at 3000 rpm/10 minutes, filtered then anhydrous sodium sulfate utilized as dry factor followed glass-fiber paper (Whatman GF/B) . In Eq. (1), measured the degradation ratio:
P = the rate of degradation of Glyphosate,
C1 = Glyphosate dose in sample.
C0 = control .
2.4 Metabolite analysis
|HPLC condition analysis|
|UV–Vis detector||254 nm|
|Manual Injector Equipped||20-μL loop|
|Mobile Phase||Acetic acid (1%) + methanol (6:4 (v/v).|
|Flow Rate||1.0 ml /min|
Pest.con = pesticide concentration in sample (mg/L)
Asa = sample peak area
Csa = sample concentration, mg/L
As = standard. peak.area
Cs = standard concentration, mg/L
3. Results and discussion
3.1 Re-growth and identification of
|Spore shape||Rod-like/ flagella spores|
|Colonies||Round to irregular /yellow to brown or black after prolonged incubation|
|Temperature||3-20 °C/ 35-45 °C,optimun30°C|
|Catalase||+||Nitrate reduction / Degradation of tyrosine||+/−|
|Starch Hydrolysis||+||Casein hydrolysis||+|
|Citrate utilization||+||Indol/ Methyl Red||—|
|Esculin hydrolysis||+||Arginine dihydrolase||—|
|Gelatin hydrolysis||+||Tryptophan deaminase||—|
Bacillus megateriumhydrolyzes and bacteria growth
3.2.1 Growth of
In Figure 1, the results show that the highest
3.2.2 Degradation rate%
The highest degradation rate% for Glyphosate by
3.2.3 Glyphosate residues by HPLC test
Organophosphorus pesticides microbial degradation and the bioremediation progress development for contaminated soils depend on the introduction of microbe’s biodegrading .
In this study,