Biology Forums - Study Force

Lo guys, im a first year science student, would be grateful for any help on this one but i have a quesition asking me to describe the similarities and differences between biological fixation of nitrogen into ammonia in plant microbes and the industrial process (Haber-Bosch) in terms of the reaction conditions. I understand how both processes work but im unable to answer this properly. Any ideas?

Lo!

In nature, the nitrogen cycle requires the works of enzymes, namely nitrogenase which converts atmospheric nitrogen (N2) into amonia. The haber-process on the other hand does not use a protein (enzyme) to convert N2 gas into amonia. Instead it uses a form of magnetite (iron oxide) as the catalyst. So you see the differene? In nature the catalyst is an enzyme whereas the haber process using a metal. In fact, this is done at 15–25 MPa (pascals) and between 300 and 550 °C, passing the gases over four beds of catalyst, with cooling between each pass to maintain a reasonable equilibrium constant. In nature, this is done at the temperature of the soil or roots and the pressure exerted by the soil.

Another difference is that in nature, nitrogen fixation is performed by bacteria, in particular Rhizobium spp., Bradyrhizobium spp., Sinorhizobium spp., Azotobacter spp., and Klebsiella spp. that live mutualistically with roots of plants. The haber process is performed in industrial scales or chemicaly in a lab.

A similarity is that both processes produce 2 molecules of amonia at the end, see:

Nature: N2 + 6 H+ + 6 e? --> 2 NH3

Haber: N2 (g) + 3 H2 (g) --> 2 NH3 (g)

Bio_man 8)

Many thank 8)

I dont feel so bad now as i was pretty much there 8)

Ta again

Pleasure.