THE EXCRETION OF CYTASE BY PENICILLIUM PINOPHILUM. 1 



By Karl F. Kellerman, Physiologist in Charge of Soil-Bacteriology and Plant- 

 Nutrition Investigations. 



INTRODUCTION. 



For many years it has been apparent that the continual destruc- 

 tion of large quantities of cellulose in nature was insufficiently ex- 

 plained by the action of the processes of rapid combustion alone. 

 The biological activities of several species of bacteria and molds 

 are usually considered a satisfactory explanation of the destruction 

 of the greater portion of the cellulose annually deposited upon the 

 soil.- yet the existence of true cellulose-dissolving enzyms or cj'tases 

 even now is questioned. 3 



TECHNIQUE OF ISOLATING CELLULOSE. 



A rather simple method has been developed that seems adequate 

 for demonstrating that cytases produced by aerobic fungi may exist 

 even when separated from the living organism which produced them. 

 Swedish filter paper is dissolved in Schweitzer's reagent, precipi- 

 tated in dilute hydrochloric acid, and washed by decantation in 

 several changes of dilute hydrochloric acid and later in pure water 

 until no evidence of either copper or chlorin can be detected by 

 acid potassium ferrocyanid or silver nitrate. Appropriate quanti- 

 ties of this amorphous mass of pure cellulose are thoroughly mixed 

 with nutrient agar media, 4 tubed, and sterilized in an autoclave for 

 20 minutes at 20 pounds pressure. When the agar has cooled 

 almost to the congealing point it is well to shake the tubes gently 



i Issued Mar. 22. 1913. 



= Kellerman, Karl P., and McBeth, I. G. The fermentation of cellulose. Centralblatt 

 fur Bakteriologie, Abt. 2, Bd. .'54, no. 18/22, p. 485-404, 2 pi.. 1912. 



McBeth, I. G., and Scales, F. M. The destruction of cellulose by bacteria and fila- 

 mentous fungi. U. S. Department of Agriculture, Bureau of Plant Industry, Bulletin 

 266, 50 p., 4 pi., 1913. 



3 Ruler, Hans. General Chemistry of the Enzyms. Tr. from the rev. German ed. by 

 Thomas H. Pope. New York, 1912, p. 13. 



4 The medium most frequently used is composed of cellulose, 5 grams; agar, 10 grams; 

 potassium phosphate, dibasic, 0.5 gram; magnesium sulphate, 0.5 gram; sodium chlorid, 

 0.5 gram ; ammonium sulphate, 1 gram ; calcium carbonate. 1 gram ; tap water, 1,000 

 cubic centimeters. 



29 

 [Cir. 118.] 



