Survival of cryogel-immobilized Rhodococcus strains in crude oil-contaminated soil and their impact on biodegradation efficiency

In laboratory microcosms, we studied the survival and catabolic activity of cryogel-immobilized and free Rhodococcus strains introduced into loam soil freshly contaminated with crude oil, mimicking spill situation. Inoculated Rhodococcus erythropolis and Rhodococcus ruber were monitored in soil and poly(vinyl alcohol) cryogel granules by selective agar plating and species-specific PCR. Introduced Rhodococcus cultures survived successively in oil-contaminated soil for 14 months. Moreover, immobilized cells demonstrated higher viability under soil desiccation conditions compared to free cells. Soil microcosms with immobilized Rhodococcus cells respired more actively than control (non-inoculated) and liquid culture-amended soils; that was in a good correlation with greater oil degradation rates in immobilized systems. (c) 2012 Elsevier Ltd. All rights reserved.