| Bioremediation is regard as an economic, practical and no second pollution technology. But the outside environment has a strong influence on the bacteria and most of the bacteria obtained are observed in liquid medium. It is not convenient for the practical application of the bacteria. Microbial microencapsulation is a technique to protect active materials from environmental hazards such as oxygen, moisture, light, etc that may cause its deterioration by the method of physical, physicochemical and chemical using natural and synthetic polymers material as wall materials.This paper studies the microencapsulation of the gram-negative bacteria for soil bioremediation. The main content of this study is the influence of the key operational parameters of spray drying on the bacteria survival rate, and the investigation of the performance of the bacteria in the microcapsule.Some key operational parameters, such as the inlet air temperature, the feed flow rate, the ratio of the wall material and atomizer rotational speed etc are determined to some extent by the single factor analysis. Furthermore. the optimum condition of spray-drying is achieved by orthogonal experiment, including inlet air temperature of 160℃, the feed flow rate of 12.5ml/min, the ratio of 1:9 for materials gum arabic and maltodextrin and 50ml for the fluid nutrient medium with bacteria. The bacteria survival rate reaches 84.57%.Finally, the microencapsulation product has been characterized and the storage performance of the microcapsule and the performance of the bacteria in the microcapsule after 6 months preservation have been investigated. The results show that the quantity of the viable gram-negative bacteria is increased and the viability of the bacteria is improved compared to those inoculated from the biology laboratory. The spray drying technology is a good method for the preservation of the bacteria and shows a great prospect in the industrial application of the soil bioremediation gram-negative bacteria.
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