SPRAY-DRYING OF THE DEHALOGENATING BACTERIUM RHODOCOCCUS SP

The bacteria Rhodococcus sp. and Xanthobacter autotrophicus have the ability to dehalogenate a broad range of halogenated hydrocarbons. The applicability of spray drying to the preservation of the microorganisms and the intracellular enzyme halidohydrolase (E.C.3.8.1.1) was examined. K2SO4, MgSO4, glutamate and sucrose were added as stabilizers and carriers. Spray drying was carried out at inlet air temperatures of 100-120 degrees C and outlet air temperatures of 65-72 degrees C. Best results were obtained by the addition of 5% K2SO4 and at 107 degrees C air inlet temperature. Dried preparations of Rhodococcus sp. exhibited a crystalline consistency and a 95% recovery of cellular activity. After storage at 4 degrees C for six months the enzyme preparation showed no loss in activity. Spray dried preparations of Xanthobacter autotrophicus showed only a 4% recovery of cellular activity.