Factors affecting lecithinase activity and production inClostridium welchii

Abstract

SUMMARYA variety of factors that affect lecithinase activity and lecithinase production byCl. welchiiwere studied. The lecithinase activity was time and temperature dependent. The optimum temperature varied from 30° to 46° C. according to the strain ofCl. welchiiemployed. Maximum lecithinase activity was produced after 12–60 hr. There was considerable strain variation. This could easily account for the differences in the published data.Commercial purified lecithinase was more readily destroyed by heat than the lecithinase produced byCl. welchiiin culture media. The enzyme inactivation pattern at 60° C. was similar to that at 90° C. This is not in agreement with the reports of others who found that less enzyme was inactivated at the higher temperatures.Acid pH values completely inactivated the enzyme. However, alkaline pH values did not significantly destroy the enzyme. The lecithovitellin reaction was completely inhibited at pH values of 1–5. The optimum pH for the reaction was around pH 7–8.The production of lecithinase was dependent upon the pH of the culture medium. One strain produced measurable lecithinase at pH values of 5·5–8·5, whereas another strain produced lecithinase only at pH values 6–5–7–5.Lecithin stimulated the production of lecithinase in a chemically defined medium.

Formation of Phospholipase C and Theta-haemolysin in Pre-reduced Media in Batch and Continuous Culture of Clostridium perfringens Type A

“…Induction of phospholipase C by lecithin has been reported (Nakamura et al 1969) but this was not confirmed (Table 2). Pivnick et al (1964) and Hauschild (1966) reported that yields of alpha-and theta-haemolysin as well as epsilon-and kappa-toxins from C. perfringens type C and D were higher upon growth in static culture with pH control than in cultures without.…”

“…2). The optimum temperature for alpha-toxin synthesis was studied by Nakamura et al (1969) who found great variations between different strains. Our results (Fig.…”

“…Few studies on the production of toxins by type A strains have been carried out under conditions of pH control (Gale & van Heyningen, 1942;Nakamura, Schulze & Cross, 1969). However, to obtain good yields of the toxins of a type C strain strict control of the pH was important (Pivnick et al 1964).…”

Clostridium Perfringens Food Poisoning

“…Weiss & Strong (200) also reported toxin activity to be reduced more at 75°C than at 100°e. These observations could not be completely confirmed by Nakamura, Schulze & Cross (130) and Nakamura & Cook (126).…”

“…Gale & van Heyningen (43) stated that, in the absencc of glucosc, best production oc curred at pH 6.0, whereas in the presence of glucose this occurred at pH 7.0-7.5. The data of Nakamura et al (130) suggest that the optimal pH for growth and alpha toxin production may depend upon the strain of C. per fringens studied. For example, strain BP6K produced alpha toxin over a pH range of 5.5-8.5 with a maximum at pH 6.5-7.5, while strain Hobbs 3 syn thesized it at pH 6.5-7.5 with a maximum at pH 6.5.…”