Enzymatic characterization ofBacilli from food packaging paper and board machines

Summary Aerobic spore-forming bacteria were found dominant in the microflora of food packaging paper and board. Twenty-five strains of bacteria belonging to the genusBacillus were isolated from these paper and board machines, papermaking chemicals, and final products of papermaking. Nineteen strains were analyzed for production of -amylase, -glucosidase, glucoamylase, pullulanase, -glucanase, carboxymethyl cellulase, and caseinase, and also for resistance towards industrial biocides. pH and temperature optima for the activity of the enzymes were determined. All strains were found to produce one or more of the enzymes studied. The amylolytic enzymes of most strains had high temperature optima for activity. Vegetative cells of all strains were found very resistant towards the different commercial slimicides used in paper and board mills. This property together with the ability to survive through the dry end of the machine to the final board and paper, and the production of enzymes degrading papermaking chemicals makes these bacteria potentially harmful in paper and board mills.