Microbial degradation of pesticides can help decrease their load in soil. Many microorganisms like bacteria, actinomycetes and fungi are able to degrade pesticides by using them as an energy source. Biodegradation is influenced by the interaction of microbes, soil properties, and pesticides. Key physicochemical soil factors like pH, moisture, and organic matter impact the degradation rate, with moisture generally favoring faster degradation due to increased microbial activity. Hydrolytic reactions are often the first step in microbial metabolism of pesticides. Management practices such as tillage and manuring can also affect soil characteristics and microbial properties involved in pesticide breakdown.

1. EFFECTS OF PHYSIOCHEMICAL
FACTORS ON BIODEGRADATION OF
PESTICIDES.
Practical assignment
Submitted to :dr.ishtiaq ahmad
By:rabia naeem (2018-amj-001)
Nimra yaseen( 2018-amj-022)

2. Microbial degradation of pesticides
To decrease the load of pesticides in soil ,degradation by
micro organisms has given sufficient encouragement,
MO transforms or inactivate pesticides. soil
microorganisms make use of the pesticide or pesticide
metabolite as an energy or nutrient source, resulting in
decreased persistence of the pesticide

3. • Many micro organism like bacteria , actinomycetes and
fungi are found to degrade pesticide:
bacteria pesticides fungi pesticides
achromobacter DDT, carbaryl Aspergillys spp. Atrazine,
simagine
agrobacterium Chlorophan Penicillium
chrysogenum
parathion,dieldri
n
enterobacter DDT Candida
tropicals
phenols
micrococcus Aldrin, dieldrin phanerochaeta DDT
nocardia Phenolic
pesticides
Sachromycese
spp.
thiocarbonates

4. • Biodegradation is influenced by microbe-soil-pestiside interaction
• Soil factors includes PH, soil moisture,organc matter
• PH
degradation rate of pesticides is slow in soils with a pH of < 6.0
because Strong adsorptlve bonds between the pesticides and soil
colloids, coupled with a low bacterial activity, may contribute to the lack
of enhanced degradation in acidic soils
MOISTURE
soil moisture favors faster degradation because of increases in
microbial activity in moist soils.
ORGANIC MATTER
Soil organic matter content limits the availability of pesticide to
microorganisms by increasing adsorption and does not seem to favor
microbial catabolism of pesticides

5. • HYDROLYTIC REACTONS
• hydrolytic reactions are the most significant ones in the
microbial metabolism of pesticides
• Pesticide catabolism by adapted soil microorganisms
usually involves an initial hydrolysis, followed by further
metabolism and utilization of hydrolysis products as
carbon or nutrient sources
• The presence of p-nitrophenol, a hydrolysis metabolite of
parathion, has been reported to induce accelerated
degradation of parathion, with an increase in the
population of parathion-hydrolyzing microbes that utilize
p-nitrophenol as the energy source for their proliferation

6. • MANAGEMENT PRACTICES
• Management practices used In crop production, including
tillage and manuring, affect a number of factors such as
physical, chemical, and biological characteristics of the
soil, microbial activity, and microbial diversity .
•