Studies of Agar-digesting Bacteria

Abstract

3 new spp. of bacteria (isolated from a trickling filter receiving a creamery waste) capable of liquefying or softening agar are described: Achromobacter pastinator (p.442), a Gram-negative short rod, motile by peri-trichous flagella, producing an almost colorless growth on solid media and rapidly liquefying agar; Pseudomonas lacunogenes (p.447), a Gram-negative short rod, motile by a single polar flagellum, producing a light orange-yellow pigment on solid media and softening agar media; and P. segne (p.452), a Gram-negative short rod, motile by a single polar flagellum, producing an orange-yellow pigment on solid media and softening agar. The last does not utilize (NH4)2SO4 as N source, hydrolyze starch or produce a pellicle on broth, as does P. lacunogenes. A marked change in viscosity of agar solutions was brought about by these organisms; chemical analysis was resorted to for testing their utilization of the various carbohydrates, since acid was not produced in sufficient quantities to be used as an indicator.