9J4 RESPIRATION 



than the Embden-Meyerhof, wc may consider ethanol production as 

 at least suggestive of the pathway. Formation of ethanol from glucose 

 is rather common among the fungi. Early work, chiefly with species 

 of Aspergillus, Fusarium, Mucor, and Penicillium, is reviewed by 

 Wehmer (317), Czapek (69), and Foster (84). A number of the wood- 

 destroying basidiomycetes form detectable amounts of ethanol in 

 culture (178, 221, 232, 233, 319); other ethanol producers include 

 Ashbya gossypii (194), Rhizopus spp. (121, 310, 314), Diplodia 

 tubericola (121), Dematium pullulans (278), Mortierella spp. (233), 

 Neurospora crassa (232), Stemphylium radicinum (178), and, probably, 

 several of the Fungi Imperfecti (20). The most active producers are 

 in the genus Fusarium, and, as will be seen later, a functional Embden- 

 Meyerhof pathway is present in F. lini. 



Under the usual experimental conditions ethanol is oxidized con- 

 currently with its formation, so that an accurate stoichiometry is im- 

 possible (5, 194, 255). However, under anaerobic conditions not 

 permitting either growth or ethanol oxidation it has been possible to 

 show that the production of alcohol and carbon dioxide from glucose 

 follows the quantitative predictions of the Embden-Meyerhof pathway 

 (62, 290, 302). Species of a given genus vary considerably in their 

 accumulation of alcohol under growth conditions; this has been 

 studied especially in Aspergillus (21, 292, 333). 



Ethanol production by fungi is generally favored by restricted 

 aeration (168, 285, 290), although even under conditions of rapid 

 aeration some fungi form large amounts of alcohol (176, 314). The 

 accumulation of ethanol, like that of other carbon-containing metab- 

 olites, is greatest in media relatively high in carbohydrate (146) and 

 low in nitrogen and minerals (243). 



Ethanol oxidation in Fusarium lini is a special case of a more 

 general capacity to oxidize primary and secondary alcohols (111, 112); 

 ethanol is oxidized to acetaldehyde, 2-butanol to 2-butanone, and 2,3- 

 butylene glycol to acetoin. 



Acetaldehyde, the precursor of ethanol in the yeast fermentation, is 

 formed, sometimes in appreciable amounts, by growing cultures or 

 resting preformed mats of several fungi (16, 22, 27, 171, 176, 211, 221, 

 255, 257, 279, 286). Most of these forms are ethanol producers, and 

 the acetaldehyde may be formed either as a precursor of ethanol or 

 during oxidation of it (112). 



In the yeast fermentation small amounts of glycerol are formed; 

 more is produced in the presence of sulfite or at alkaline pH. The 

 same observations have been made with fungi (211, 287). 



Pyruvic acid is frequently produced in isolatable amounts by fungi 



