SELECTED PAPERS 



licheniformis converts nitrate into a mixture of nitrogen and nitrous 

 oxide, the fact that under moderate aeration these reduction products 

 are replaced by ammonia favours the idea of a common precursor for 

 both types of products, as accepted in the scheme given above. In some 

 way free oxygen should then counteract the dimerization of the interme- 

 diately formed HNO, thus preserving it for further hydrogenation. 



How this may be, Verhoeven's observations on the ammonia pro- 

 duction from nitrate brings the dissimilatory nitrate reduction fully in 

 line with dissimilatory processes like respiration, sulphate and car- 

 bonate reduction, as is evidenced by the following equations : 



2 +4H -> 2 OH 2 

 H 2 S0 4 +8H -> SH 2 +4H 2 

 H 2 C0 3 +8H -> CH 4 +3H 2 

 HNO3+8H -> NH 3 +3H 2 



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