Abstract
(1) Cellulase (Cx) of phytopathogenic bacteria, twenty-eight species and one variety belonging to five genera, was detected when they were cultured on CMC-gel medium prepared by dissolving 2 percent of carboxymethyl-cellulose (CMC) into various basal media (Table 1). Cx enzyme was commonly produced by xanthomonads and all strains of Erwinia carotovora, serologically identified by the authors, though they show various degrees of activity according to each bacterium, while most pseudomonads, except P. solanacearum and P. panici, did not show the production of cellulase (Cx) on any medium tested. Erwinia milletiae and Corynebacterium sepedonicum produced the enzyme on only potato-CMC-gel medium, the most suitable one for the detection of cellulase (Cx), prepared by adding CMC into potato decoction (see Table 2).
(2) The cellulase (Cx) activity of phytopathogenic bacteria was represented by percent loss in viscosity of one percent solution of CMC. It reacts with the reaction of linear equation, since reaction time necessary for reaching to fifty percent-loss in viscosity of CMC solution did not connect with the concentration of the substrate (see Table 3).
(3) Change of cellulase (Cx) activity in filtrate of 10 days culture in bouillon or potato decoction with or without CMC, was different corresponding to the bacterial species or strains tested (see Fig. 1).
When the velocity constant k of the linear equation is adopted as the standard of the enzyme activity, cellulase (Cx) in culture filtrate of bouillon or potato decoction containing 0.2 percent CMC increased its activity in a straight line with the culture duration in the case of Erwinia carotovora strain chrysanthemi. In the case of Xanth. campestris, however, the conspicuous decrease of activity followed its very rapid increase within 3-day-incubation period (see Fig. 2). Although the probable production of a proteinase is responsible to such prompt decrease of cellulase activity, its presence may be made evident elsewhere. In the case of Pseud. solanacearum the activity was observed to increase in a straight line during five-day incubation, but then stabilized at this level until 10 days. This stabilization of enzyme activity of P. solanacearum is supposed to be caused by the rapid loss in vitality of this bacterium usually occurring in bouillon or potato decoction medium. Cellulase (Cx) was produced under the cultural conditions without CMC (β-1.4 glucosidic linkage), though the activity was relatively low as compared with that under its presence.
