ECONOMIC USES OF LICHENS — LLANO 405 



factories in Kirovsk have demonstrated the possibility of subjecting 

 lichens to preliminary treatment with weak alkali solution in order 

 to convert the bitter-tasting lichen acids into soluble form. This is 

 then hydrolyzed with dilute H2SO4, neutralized with chalk, and puri- 

 fied with activated charcoal to produce a molasses containing 65 to 

 70 percent glucose. From this, crystallized (lump) glucose was ob- 

 tained. The yield of molasses was 100 percent, based on dry lichen 

 weight. However, molasses produced by this process from lichens 

 of the Cladonia group, especially alyestris^ has a bitter taste, ''the 

 cause of which the authors are investigating.'' 



Lichens vary in the amount of carbohydrates (lichenin) present. 

 Cetraria islamdica and Cladonia rangiferma have been found to yield 

 up to 66 percent of polysaccharides which are readily hydrolized to 

 glucose and then almost completely fermented to alcohol. Besides 

 sugars capable of fermentation, lichen acids up to 11 percent of air- 

 dried substance may be present. These acids as well as sodium chlo- 

 ride have been found to retard the process. Experiments with 

 Cladonia rangiferina have shown a total yield of 54.5 percent sugar 

 which on fermentation produced 176 to 282 cubic centimeters of alcohol 

 per kilo. Maximum returns of alcohol were obtained by steaming the 

 lichens 1 hour under the three atmospheres pressure, adding 25 percent 

 HCl, resteaming for the same period of time and pressure, and finally 

 neutralizing the product. Subsequent growth of yeast was normal, 

 though fermentation could be accelerated by addition of H3PO4. An 

 interesting modification of this procedure through addition of three 

 parts by weight of H2SO4 and one part by weight of NCI at room 

 temperature gave a pentanitrate similar to cellulose nitrate which, 

 on gelatinizing with a solvent, produced a substance resembling 

 horn (13). 



Tanning. — Tlie tanning quality of lichens is due to an astringent 

 property (depsides) peculiar to some species. Cetraria islandica and 

 Loharia pulmonaria are most frequently used, and, though not occur- 

 ing in quantities sufficiently large to warrant industrial application, 

 have been locally employed on a small scale. 



Dyeing. — Synthetic dyes have largely replaced many formerly 

 common vegetable dyes in the textile industry, primarily because of 

 their low production cost and the fact that they generally surpass the 

 natural products in fastness, particularly light fastness. Of the 

 vegetable dyes, those obtained from lichens were renowned among 

 the peasant dyers of old for their high quality and color, but today are 

 the least known. Some of them are still popular in rural districts of 

 Great Britain and the Western Islands, Iceland, Scandinavia, France, 

 and Germany. Interest in lichen dyes is being revived today some- 

 what in Scandinavia because of their use by the Hemslojd (Home 

 Industries Association) , while there is some indication that the Irish 



