PRODUCTS OF THE LOWER FUNGI 295 



high from pentoses and glycerol as it is from hexoses, 

 which suggests that it is not formed by a series of oxido- 

 reductions from glucose, for instance, as its structure 

 would at first sight indicate : — 



M^OlRl CO 



HOCiHiiHOiCH ^ HOC CH 



|i :.:": M " II II 



HCiOHi-HiCCHaOH HC CCH^OH 



XoT^ Xo/ 



(glucose) (kojic acid) 



It appears more likely that the sugars first of all undergo 

 breakdown to a common intermediate which is then 

 built up into kojic acid. The intermediate appears not 

 to be acetaldehyde since the formation of kojic acid is 

 not hindered by fixation of acetaldehyde by dimedon or 

 sulphite. Aspergillus flavus and A. parasiticus, which 

 both produce kojic acid from glucose in culture, when 

 plasmolysed by chloroform or toluene, convert starch, 

 maltose, sucrose or glucose into glucosone, CHoOH. 

 (CHOHJaCO.CHO. ^4. flavus converts glucosone into 

 kojic acid in normal culture, suggesting that glucosone 

 may be an intermediate between glucose and kojic acid. 

 A less likely alternative is that all sugars are first con- 

 verted into a single reserve polysaccharide and that this 

 is the source of the sugar which is the immediate precursor 

 of the kojic acid ; thus five hexose units might unite to 

 give a C30 polysaccharide, and six pentose units or ten 

 triose units condense to give the same polysaccharide. 

 The difficulty is that the number of oxygen bridges 

 would be different in each case. A further objection to 

 the suggestion that reserve carbohydrates are involved 

 is that kojic acid is not formed when dry mycelium is 

 used as carbon source for the mould. 



Challenger has suggested that kojic acid may arise by 

 the condensation of two molecules of dihydroxyacetone 

 and oxidation : — 



