Patent GB-731804-A (GB)
Title: A process of oxidative fermentation of alcohols and apparatus for carrying out the same
IPC: C12J1/10
Filed: 1951-08-16
Abstract: <PICT:0731804/IV (b)/1> Acids are prepared by an oxidative fermentation of alcohols which comprises pretreating air by passing it through fresh or partly fermented alcohol-containing fermentation liquid contained in an air-pretreating means and thereafter introducing the pretreated air into a mass of filler material carrying oxidizing bacteria and separately feeding alcohol-containing fermentation liquid to the filler material.  The pretreatment serves to remove from the air agents tending to poison the bacteria on the filler material. Suitably, the fermentation liquid in the pre-treating means contains oxidizing bacteria whereby the alcohol in the liquid is also oxidized to acids by submerged fermentation. Suitable apparatus for the process comprises a fermentation generator 1 having a perforated bottom 13 supporting beech shavings 18 carrying the bacteria and an air-pretreating means 2 containing fermentation liquid and a perforated plate 10 serving as an air injector. Fermentation liquid is sprayed on to the shavings 18 from a tank 15 and a sprayer 17 and collects in the bottom chamber 14 from which it is pumped back to tank 15.  Meanwhile, air is pumped into the pretreater by a compressor 8 and a pulsating pump 12.  The pretreated air then passes into the mass of shavings via the perforated end of pipeline 4.  The pulsating pump produces pulsations in the air-feed and, in consequence, similar pulsations in the liquid in the filler material so improving the distribution of the liquid.  When the pretreatment means 2 is employed in submerged fermentation it is preferred to add wood flour, sawdust or like porous fibrous material to the fermentation liquid therein to facilitate bacterial growth. The apparatus may be modified whereby the pretreatment means is arranged within the collecting chamber 14 of the generator or the perforated plate 10 of the pretreater may be built into the collecting chamber whereby the latter serves also as the pretreater. According to one example, a fermentation liquid containing 3.8 per cent ethanol and 6.4 per cent acetic acid is recirculated continuously in the generator system and is passed into the pretreater containing fermentation liquid of the same kind; the generator thus converts to acetic acid 7.8 litres of alcohol per cubic metre of shavings per day as compared with a conversion of 2.5 litres in absence of the air-pretreatment.  In another example, the pretreater is provided also with the same bacteria as the generator and sawdust is added, the pretreatment resulting in submerged fermentation.  The apparatus shown is so adapted that on closing valves 7, 19 and 25, the pretreater and generator may be operated independently and in a further example, fermentation of the ethanolic liquid is effected in both vessels operated together as in the previous examples; then fermentation is effected in the two vessels independently, air being supplied direct to the generator via pump 21 and line 22; finally the sawdust is removed from the pretreater and the two vessels again operated jointly.  The process may also be applied to the production of vinegar, as described in Specification 352,740, [Group VI], propionic acid from n-propanol, butyric acid from n-butanol, and citric acid from ethanol using Aspergillus niger as bacteria; gluconic acid may be produced using acetic bacteria.