The answers to these questions are covered both in the lecture material and the text book What reaction, oxidation or reduction, is key to uranium bioremediation? How does the role of energy production lead to the action of bioremediation by microorganisms? What are xenobiotics and what are some examples? What is the role of microbes in the bioremediation of xenobiotics? Explain how the bioremediation of the herbicide 2, 4, 5-1 shown below, produces energy lord microbes. Solution 1. Bioremediation is a process which involves the use of microorganisms to remove or neutralize from contaminants, such as polluted soil or water. In the absence of oxygen, bacteria are able to respire various electron acceptors for the energy required for its metabolism. At the environmentally neutral pH, the aquaous U has a similar redox couple to Fe(III), therefore Fe(III)-reducing bacteria are able to respire aquaous U as an alternative electron acceptor, reducig it to insoluble U. Reduction of Uranium is the key reaction for the bioremediation of uranium, For the bioremediation of Uranium the process is stimulated by adding electron donor such as acetate, lactate or ethanol from which electrons can be taken up by bacteria to gain the energy to promote the enzymatic (microbial) reduction of aquaous U to insoluble U in anaerobic condition. The end product of this process would be uraninite. 3. Xenobiotics are the synthetic compounds found in living organisms, which are not produced by and foreign to that organisms. They are also synthetic substances (doesn\'t produced naturally) which are found in higher concentration than its normal level in the entire biological system. Examples of xenobiotics are: Halocarbons: consist of halogen group in their structure and used in solvents, pesticides, propellents etc. Due to their volatile nature, they often escape and destruct the ozone layer. Synthetic polymers: mainly used to form polyester, polyvinyl chloride etc Carcinogen, food additives, drugs are also examples of the xenobiotics. Normally the degradation of xenobiotics by microorganisms is very rare, as the availability of the xenobiotics to the microorganisms is very low as compared to its concentration in environment. However, when certain microbes are exposed to these xenobiotics continuously, they develop the ability to degrade the compounds. Mutations in microbes occur in such a way so that its active site can shows increased affinity towards the xenobiotics and some mutates to form new enzymatic pathway for degradation of xenobiotics. Use of mixed population is very effective for bioremediation of xenobiotics. It creates the cometabolism process n their combined effect is higher than the individual alone. Genetic engineering can also be used to modify microbes for degrading xenobiotics. 4. The microbes while degrading herbicide 2,4,5-T, it produces an end product named succinate + acetate. Succinate is the intermediate of the TCA (TriCarboxylicAcid) cycle, so it.

1. The answers to these questions are covered both in the lecture material and the text book What
reaction, oxidation or reduction, is key to uranium bioremediation? How does the role of energy
production lead to the action of bioremediation by microorganisms? What are xenobiotics and
what are some examples? What is the role of microbes in the bioremediation of xenobiotics?
Explain how the bioremediation of the herbicide 2, 4, 5-1 shown below, produces energy lord
microbes.
Solution
1. Bioremediation is a process which involves the use of microorganisms to remove or
neutralize from contaminants, such as polluted soil or water. In the absence of oxygen, bacteria
are able to respire various electron acceptors for the energy required for its metabolism. At the
environmentally neutral pH, the aquaous U has a similar redox couple to Fe(III), therefore
Fe(III)-reducing bacteria are able to respire aquaous U as an alternative electron acceptor,
reducig it to insoluble U. Reduction of Uranium is the key reaction for the bioremediation of
uranium, For the bioremediation of Uranium the process is stimulated by adding electron donor
such as acetate, lactate or ethanol from which electrons can be taken up by bacteria to gain the
energy to promote the enzymatic (microbial) reduction of aquaous U to insoluble U in anaerobic
condition. The end product of this process would be uraninite. 3. Xenobiotics are the synthetic
compounds found in living organisms, which are not produced by and foreign to that organisms.
They are also synthetic substances (doesn't produced naturally) which are found in higher
concentration than its normal level in the entire biological system. Examples of xenobiotics are:
Halocarbons: consist of halogen group in their structure and used in solvents, pesticides,
propellents etc. Due to their volatile nature, they often escape and destruct the ozone layer.
Synthetic polymers: mainly used to form polyester, polyvinyl chloride etc Carcinogen, food
additives, drugs are also examples of the xenobiotics. Normally the degradation of xenobiotics
by microorganisms is very rare, as the availability of the xenobiotics to the microorganisms is
very low as compared to its concentration in environment. However, when certain microbes are
exposed to these xenobiotics continuously, they develop the ability to degrade the compounds.
Mutations in microbes occur in such a way so that its active site can shows increased affinity
towards the xenobiotics and some mutates to form new enzymatic pathway for degradation of
xenobiotics. Use of mixed population is very effective for bioremediation of xenobiotics. It
creates the cometabolism process n their combined effect is higher than the individual alone.
Genetic engineering can also be used to modify microbes for degrading xenobiotics. 4. The
microbes while degrading herbicide 2,4,5-T, it produces an end product named succinate +
acetate. Succinate is the intermediate of the TCA (TriCarboxylicAcid) cycle, so it can enter TCA
which ultimately leads to production of energy via electron transport of Oxygen. Acetate is also a

2. fermentation product which gives energy to the microbial cell important for their growth and
activation. Thus by degrading the herbicide, microbes get these two important metabolism
intermediate and produce energy by using them