242 BACTERIOLOGICAL CHEMISTRY 



2. CH3. M (.'Hg.^ 



>C< + O ^ >(!-() ■+ HgO 



CH3/ \UH CIH3/ 



isopropyl alcohol) (acetone) 



3. (a) — CHOH O /OH OH 



I // / / 



I C-H C^ — OH C = 



O (CH0H)3 1 I 



+ H2O I ^H +0 I 



I > (CH0H)4 > (CH0H)4 > (CH0H)4 + HgO 



OH I I I 



CH2OH CH2OH CH2OH 



CH2OH 



(glucose) (glucose hydrate) (gluconic acid) 



(6) OH OH 



/ / 



c=o c=o 



(CH0H)3 + O > (CH0H)3 + HoO 



HCOH CO 



CH2OH CH2OH 



(gluconic acid) (5-ketogluconic acid) 



A. suhoxydans oxidises glucose to gluconic acid and 

 5-ketogluconic acid in an acid medium ; if the medium 

 is kept natural by carrying out the fermentation in 

 presence of calcium carbonate, 2-ketogluconic acid is 

 formed. 



The point to be noted in each of these examples is 

 the activation of two hydrogen atoms (shown in bold 

 type in the formulae) and their transfer to an oxygen 

 atom. The reactions can all be induced to occur anaerobi- 

 cally if a suitable hydrogen acceptor like methlyene blue 

 is provided in place of the oxygen. A. suhoxydans 

 restricts its activities to the oxidation of the secondary 



alcohol group, ^CHOH, to the keto group, ^C = 0, but 

 A, xylinum, Bertrand's sorbose bacillus, which also 

 oxidises the same group in the same way, producing 

 /-sorbose. 



