A strain of Achromobacter iophagus isolated from cured hides was shown to lyse collagen rapidly under aerobic conditions. Changes of temperature, pH, NaCl or collagen concentration affected either the maximum rate of collagen lysis or the lag before this rate was attained, or both. Collagenolytic activity occurred in 0.85 to 1 0 % (w/v) NaCI. Collagenolytic activity by hide bacteria is regarded as the cause of leather decay and thus a knowledge of the conditions under which these bacteria can degrade collagen is important to the hide and skin industry. The present study of a vigorously collagenolytic hide bacterium aimed to determine the optimal conditions for collagenolytic activity with a view to purification of the collagenase.
I N T R O D U C T I O N
M E T H O D SAll percentage compositions are wiv and all nutrients are Difco (Detroit, Michigan, U.S.A.) unless stated otherwise.Source and identification. The bacterium was isolated from a batch of South African cured hides whose bacterial population possessed a high collagenolytic activity (Woods, Welton, Thomson & Cooper, 1972 (Skerman, I 967).Media. The bacterium was maintained on a complex medium containing (g/l): casein hydrolysate (British Drug Houses, Poole, Dorset and Merck AG, Darmstadt, Germany), 17.0; glucose, 5.0; glycerol, 10.0; NaCI, 23.4; Na,SO,, 0 . 1 ; nutrient broth, 8.0; soytone, 3.0; tryptone, 0.5; vitamin-free Casamino acids, 0.5; yeast extract, 2-0; and agar, 15.0. The pH was adjusted to 7.6 with NaOH. Owing to the rapid spreading of the bacterium, this medium was not suitable for isolating clones. Discrete colonies were obtained on a medium consisting of: minimal salts solution, 125 ml; glucose, 2 g; agar, 15 g; distilled water to I 1. The minimal salts solution contained (g/l) : KH,PO,, 8 ; K,HPO,, 24; MgS04. 7H20, 0.8 ; Na,SO, (anhydrous), 16; NH,CI, 40; and NH,NO,, 8.
