Patent GB-458922-A (GB)
Title: Improvements in or relating to manufacture of solvents by fermentation
IPC: C12P7/28
Filed: 1935-03-23
Abstract: Butyl and isopropyl alcohols and acetone are produced by fermenting a sugary mash with bacteria characterized by their inability to liquefy gelatine, their inability to produce appreciable amounts of solvents in a mash consisting solely of cereal starch and water, their giving a positive fermentation test for glycerol and sucrose and their capacity to produce the above solvents, the ratio of the acetone and isopropyl alcohol produced being dependent on the hydrogen ion concentration of the mash. Mashes with pH values under about 5,5 produce mainly butyl alcohol and acetone with isopropyl alcohol present from traces up to about 10 per cent, e.g. with pH values between about 4 and 5,3, the product contains about 60 to 70 per cent butyl alcohol and 30 to 38 per cent acetone.  With higher pH values up to about 8, the product contains about 65 to 80 per cent butyl alcohol, 10 to 30 per cent isopropyl alcohol and a few up to about 20 per cent acetone.  Nutrient materials may be those in beet molasses, or proteins of animal or vegetable origin or urea.  Relatively small amounts, e.g. 0,0002 to 0,1 per cent of the mash, of ammonia or its salts or urea hasten the fermentation and also alter the relative amounts of products, less butyl alcohol and more of the lower boiling solvents, particularly acetone being produced.  The pH value is regulated by organic or inorganic acids or alkalis such as ammonia or alkaline ammonium compounds or alkali or alkaline earth oxide hydroxide or carbonate or, in molasses mashes by varying the proportions of beet and cane molasses.  Examples of the fermentation of molasses are given.  The bacteria which are named Clostridium - Saccharobutyl - isopropyl-acetonicum are obtained by methods similar up to a point for obtaining the Clostridium Saccharobutyl-acetonicum described in Specification 409,730 but carried beyond by elective culture in glycerol medium. They are obtained from potatoes, grains and other vegetable products and may be sub-cultured in 10 ccs. of a mash of 7 to 10 per cent potato and 1 to 4 per cent corn sugar in water, heating at 85 DEG  C. for 15 minutes and cooling before incubation for 15 to 24 hours at 35 to 37 DEG  C.  This culture is then used as the inoculum for about 200 to 500 c.cs. of a similar potato mash which, incubated at 35 to 37 DEG  C. for about 6 to 20 hours gives a suitable volume of inoculant for the fermentation mash. The results of bacteriological fermentation tests are given, the tests being conducted at 37 DEG  C. for 85 days, gas evolution being measured by the rise of vaseline seals in the test tubes, each of which contains 10 c.cs. of sterile liquid medium of 1 per cent carbohydrate, comprising peptone, pH value 7,1 to 7,3 over about 1 c.c. of washed sand.  The inoculum used was 8 drops of a 4 day old culture developed in veal infusion broth over inoculated brain.  The gelatine liquefaction test was made on "bacto nutrient gelatine," viz. 3 parts beef extract, 5 parts peptone and 100 parts gelatine. Specification 371,865 also is referred to.