Preparation of a bacterial cell aggregate

Claim 1

A process for producing an extruded Streptomyces olivaceus bacterial cell aggregate having improved hardness which comprises forming a bacterial cell aggregate by contacting a mass of Streptomyces olivaceus bacterial cells for 0.5 to 1.5 hours with a cross-linking reaction product of (1) a material selected from the class consisting of glutaraldehyde, cyanuric halide and combinations thereof and (2) a water-soluble cationic polymer obtained by the polymerization of an epihalohydrin with an alkylene polyamine having the formula R 1 R 2 NRNH 2 wherein R is a lower alkylene having from 2 to about 6 carbon atoms, and R 1 and R 2 are each a lower alkyl of from 1 to about 6 carbon atoms, the mole ratio of epihalohydrin to polyamine being from about 0.60:1 to about 2.7:1, said polymerization comprising reacting with the alkylene polyamine from about 50 to about 90 percent of the amount of epihalohydrin to be polymerized, allowing the reaction to continue until the reaction medium attains a substantially uniform viscosity, and reacting the remaining portion of the epihalohydrin incrementally to obtain the cationic polymer, the temperature of polymerization being from about 60° C. to about 120° C., adding to said bacterial cell aggregate a portion of previously-produced dried finely-divided bacterial cell aggregate of the same overall composition to form a bacterial cell aggregate mixture, extruding such mixture through a die of reduced cross-sectional area, drying the extrudate, and grinding and separating the extrudate to produce the desired particle size range.