Environ Exp Biol (2017) 15: 105–111

Immobilization of bacterial association in alginate beads for bioremediation of oil-contaminated lands

Abstract

Entrapment in alginate gel is a widely used approach for immobilization of microorganisms to improve their viability. A natural bacterial association consisting of seven strains isolated from acid tar-contaminated soil was used for immobilization in alginate gel. The aim of this study was to identify conditions for entrapment of a bacterial association and to determine conditions for its prolonged storage. The association was successfully immobilized in 1.5% alginate beads that were 2 mm in diameter. All tested treatments, with or without 5% clay, with or without 10% glycerol, and with or without incubation of prepared beads in nutrient medium or 0.2 M solution of CaCl₂, showed good results in terms of survival of bacteria immediately after entrapment in gel and during at least six months storage of beads at temperature of 4 and 20°C. The number of bacterial colony-forming units increased by 1.1 to 1.3 log g^–1 in clay-containing beads during the experiment, regardless of storage temperature but it remained at baseline levels in other treatments. Further studies are necessary to evaluate bioremediation activities of the immobilized association in laboratory and field conditions.