ISSN:
1435-0661
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Pseudomonas fluorescens (Migula) 2-79RN10 in the presence of various clays. Pseudomonas fluorescens 2-79RN10 was suspended in phosphate buffer, mixed into Ca2+ -saturated pyrophyllite, kaolinite, clinoptilolite, and montmorillonite (0.5 mL of cell suspension g-1 clay), and air dried at 20°C. Bacterial colony-forming units (CFU), gravimetric water, and water activity (a w) were determined whenmixed and at 9, 14, 19, 28, and 48 h after mixing. Bacterial survival was greatest in air-dried montmorillonite and lowest in kaolinite. The rate of change in a w, final a w values, and rate of gravimetric water loss were similar for all clays. However, a w values during the initial stage of drying varied because the same cell-suspension volume was amended to equivalent weights of clays possessing different surface areas. The length of time prior to decreases in a w varied in the order: kaolinite 〉 clinoptilolite 〉 pyrophyllite 〉 montmorillonite, a sequence inversely proportional to survival. Alteration of clay particle size and amendment with different cell-suspension volumes showed that increased bacterial survival could be achieved by shortening the time a w remained elevated. Increased survival of 2-79RN10 is thus promoted by cell-clay interactions resulting from more rapid decreases in a w values during the initial stages of drying. Our results have relevance to bacterial survival in clay formulations and soil.
Type of Medium:
Electronic Resource
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