Preparation of high viable count Pseudomonas putida bacteria powder by cold blast drying

Abstract:

[Objective] This study aimed to prepare high viable count Pseudomonas putida bacteria powder, and improve the viability of drying and elongate the preservation period. [Methods] We selected cold blast drying technology to prepare bacteria powder, and optimized carriers and protective agents. [Results] Viability of drying was 65% on behalf of cold blast drying, which was significantly superior to spray drying (24%). Carriers and protective agents with orthogonal experiments were applied to obtain optimal formulation of preparation bacteria powder. The result was?as follows: as bacterial cell carriers, diatomite and corncob powder pretreated by Ammonia were mixed with ratio of 1:2. 7% mannitol, 5% sodium glutamate and 1% glycerin were mixed as protectives (W/W). Viable cell count was 1.03×1011 CFU/g in instant preparation. The viability was 71.67% and 40.54% after 60 d storage at 4 °C and 30 d storage at room temperature (RT) respectively. [Conclusion] Cold blast drying had little damage to bacteria because of its relatively low temperature (10?40 °C). Corncob powder pretreated by Ammonia, mannitol and glutamate had positive effect on preservation of bacteria powder. This method was successfully applied to resolve the difficulties of long-term preservation of gram negative non sporing bacteria.

Key words:Pseudomonas putida, Cold blast drying, Carriers, Protective agents