A MUTANT OF PREVOTELLA-RUMINICOLA B(1)4 DEFICIENT IN BETA-1,4-ENDOGLUCANASE AND MANNANASE ACTIVITIES

A mutant of Prevotella ruminicola B(1)4 was isolated after chemical mu tagenesis with ethylmethanesulfonate. The mutant, MW1, did not produce polypeptides that cross-reacted with antibody to wild-type beta-1,4-e ndoglucanase and virtually no beta-1,4-endoglucanase or mannanase acti vity was detected. MW1 grew more slowly on cellodextrins and no growth was observed with guar gum (mannan) as an energy source. MW1 cultures that were repeatedly transferred with cellobiose and mannan eventuall y regained the ability to utilize mannan as an energy source, The reve rtant (MW1R) had 40 and 25% of beta-1,4-endoglucanase and mannanase ac tivities compared to wild-type B(1)4, respectively. Western immunoblot s indicated that MW1R produced a beta-1,4-endoglucanase that could cro ssreact with wild-type B(1)4 enzyme. Wild-type B(1)4 had beta-1,4-endo glucanase and mannanase activities when either cellobiose or mannan wa s the energy source, but MW1R had these activities only when mannan wa s provided.