GB692280A - A method of extracting lignin or oxidation products thereof from wood - Google Patents

Abstract

A method for recovering lignin or oxidation products thereof from wood or other ligninaceous plant materials, particularly wood refuse and sawdust, by alkali treatment of the wood, with or without simultaneous treatment with oxidizing agents, is characterized by the feature that the wood is subjected before the said treatment to the influence of dry rotting fungi and/or cellulose fermenting bacteria so as to attack, degrade, and remove the non-ligninaceous components (hemi-cellulose and cellulose) of the wood which react with and increase the consumption of alkali added at the alkali treatment. It may be advantageous to remove soluble degradation products, after the degradation treatment, by extraction with suitable solvents such as water, aqueous solutions, or one or more organic solvents, e.g. alcohols, ketones, acids, ethers or hydrocarbons. The degradation may be effected with dry rotting fungi belonging to the following families: Merulius, Lentinus, Lenzites, Conisphora, Poria, Polyporus, Phomes, Aspergillus, Penicillium, Trametes, Botrytis, Trichoderma, Fusarium and Oidium and bacteria belonging to the family Cytophaga, conditions concerning pH, moisture, temperature, admittance of air, and presence of nutrients, being adjusted for each particular species. In examples: (1) pieces of pine wood are sterilized and then placed in Kolle retorts containing a malt-agar substrate inoculated with mycelium of the fungus Lentinus lepideus. The retorts are placed in a room maintained at 22 DEG C. and having a constant reactive moisture of 80 per cent and the material removed after a suitable period, e.g. 2 to 6 months, and liberated from mycelium. The pieces are then ground and sieved and the resulting wood powder mixed with caustic soda solution and nitrobenzene in an autoclave which is then closed and placed in an oil bath maintained at 180 DEG C. for about two hours. The autoclave is then cooled, the contents steam distilled, centrifuged, acidified, and extracted with trichloroethylene to yield vanillin; (2) as in (1) except that the pine wood is subjected to the influence of Conisphora puteana.