ALCOHOL, SUGARS AND GLYCERIN. 419 



307. Destruction and Formation of other Organic 

 Substances by Mycoderma. 



In addition to the organic acids, the alcohol in beer, wine and 

 fruit wines is subjected to complete destruction by Mycoderma 

 fungi, being, on the one hand, oxidised to carbon dioxide and 

 water, and on the other employed by the fungi as an organic 

 structural material. This last circumstance was deduced by 

 A. SCHULZ (I.), who expressed the view that "the film fungus 

 is capable of itself forming its constituent organic compounds, 

 and requires only ammonia and alcohol for that purpose." This 

 opinion was confirmed by MEISSNER (XL). Schulz employed 

 in his experiments an artificial nutrient solution, containing 

 magnesium sulphate and alcohol, in addition to potassium 

 phosphate and lime. In one case ammonium nitrate was added 

 to the solution, as the source of nitrogen, asparagin being used 

 in another, and ammonium tartrate in the third. The fungus 

 thrived in all three cases, and consumed a large portion of the 

 alcohol, thus indicating the capacity of Mycoderma to supply 

 their nitrogen requirements from ammonium nitrate and to utilise 

 alcohol in the building up of their cell contents. It must, however, 

 be mentioned that Schulz did not work with pure cultures, and 

 that the race used by him apparently belonged to the genus Pichia. 

 An important complement of these experiments was afforded 

 by the investigations of Meissner, as also by the previous experi- 

 ments of WINOGEADSKY (XI.), which were afterwards confirmed 

 by A. Kossowicz (III.) see p. 209, vol. ii. These showed that 

 pure cultures of Mycoderma also exert the activity first recognised 

 by Schulz. In addition to the aforesaid nitrogenous food-stuffs, 

 MEISSNER (VIII.) used ammonium phosphate and chloride, which 

 he added to an artificial nutrient solution along with the neces- 

 sary ash constituents. The energetic growth demonstrated that 

 Mycoderma can be supplied in nitrogen by these substances as 

 well, and consequently part of the alcohol in the nutrient solution 

 is oxidised, a part being utilised in building up the cell body. 



The sugars are attacked by the various Mycoderma species in 

 a different manner and with varying intensity. H. VAN LAER 

 (VIII.), for example, reported that dextrose is not attacked in 

 Nageli's nutrient solution by Mycoderma ; whereas in yeast water 

 it forms a better food-stuff than alcohol. Maltose and saccharose 

 are attacked |in very different degree ; and in this case also it 

 appears that the degradation depends entirely on the nature of 

 the nurient material. " When different sources of carbon are 

 added simultaneously to the nutrient solution, the one that is 

 most readily assimilable is degraded first ; and it is not until the 

 alcohol has disappeared that the disaccharides are attacked." 

 When maltose, saccharose and dextrose are added to the yeast 



