The strain 4-2w was isolated from the cattles's gastric juice by enrichment culture with ricinine as a substrate.This strain was identi- fied as pseudomonas sp.4-2w according to its characteristics of physiology and biochemistry.The optimal growing temperature and pH were 36℃and 7.0,respectively.The rate of detoxification was more than 90%.And this bacterium did not use up protein of castor bean meal.