212 SECTIONAL ADDRESSES 



facture of nitro-glycerine, the most important constituent of high explo- 

 sives. The blockade of the Allies prevented the import into Germany of 

 fats and oils utilised in the preparation of glycerine, and attention was 

 therefore paid to the possibility of its production by fermenting sugar 

 which was available as raw material. Ordinary fermentation of sugar 

 takes place either in neutral or slightly acid solution, but for over sixty 

 years it has been known that it can proceed in the presence of various 

 alkaline salts. The fermentation reaction proceeds instantaneously and 

 it is impossible to gain an insight into the mechanism of the process by 

 isolating an intermediate product. C. Neuberg has given a scheme for 

 alcoholic fermentation which shows methyl-glyoxal as the probable 

 first stage of the process ; this is oxidised to pyruvic acid, which is in its 

 turn decarbonylated to acetaldehyde and carbon dioxide. The problem 

 which was tackled was whether the acetaldehyde could be ' trapped ' 

 before it had been oxidised or reduced. Theoretically then for every 

 molecule of acetaldehyde fixed a corresponding molecule of glycerol is to 

 be expected. W. Connstein and K. Ludecke in 1914 began by adding a 

 number of alkaline compounds such as sodium carbonate and sodium 

 acetate. Infection by lactic-acid bacteria, however, occurred to such an 

 extent that not only was a large quantity of sugar consumed but the glycerine 

 was so contaminated that it was difficult to purify. The alkaline salts 

 were next replaced by disodium sulphite, which, when added to the mash 

 even in very considerable quantities, does not interfere with the action 

 of the yeast, and in addition is a valuable antiseptic. This method 

 was patented in 191 5. Apparently it was learned in the United States 

 that ' the Germans were producing glycerine in large quantities by a 

 fermentation process, sugar being the material used,' and federal chemists 

 were set to work on a similar investigation. The general theoretical 

 reasoning again proved fruitful, and successful methods were worked 

 out and patented in the United States, England, the former Austria- 

 Hungary, Switzerland and Japan. During the War the monthly German 

 production of glycerine by this method exceeded 1,000,000 kilograms and 

 twenty to twenty- five per cent, of the sugar used was converted into 

 glycerine. In the United States twenty per cent, glycerine was obtained 

 by fermenting molasses and syrups with Californian wine yeasts. The old 

 method of commercial production has now been reverted to more or less 

 generally because of being the more economical. 



In recent years the use of commercial diastase (Takadiastase, Kashi- 

 wagi-diastase, Digestin, Protozyme, Oryzyme, Polyzyme and other trade 

 names) has spread extensively especially in America ; it originated in 

 Japan. The diastase is of fungal origin, being manufactured from Asper- 

 gillus flavus-Ory zee, the species of Japanese koji. Cultivation is carried 

 out on bran (wheat-bran in U.S.A., rice-bran in Japan) or some other 

 cheap, bulky, fibrous substance, sterilised, moistened and spread out on 

 trays. Inoculation is made at a suitable temperature and the fungus 

 rapidly extends over the mass. Growth is stopped at the time of maximum 

 enzymic activity, which is soon after spore-formation, the resulting 

 liquid is then pressed through percolators and filtered through infusorial 

 earth or merely strained. For commercial use the extract is preserved by 



