The study for microorganisms immobilizing to restoration crude oil contaminated-soil

Diatomite was selected as amendment for alginate beads for the aim to immobilize microorganisms to restoration crude oil contaminated-soil. The optimum ratio of sodium alginate and diatomite in the bead was separately 6% and 2%. For complete gelation and highest cell activity, the beads were incubated in calcium chloride sterile solution for 12 h. The obtained indigenous hydrocarbon-degrading microbial community was immobilized in sodium alginate beads (SA) and sodium alginate-diatomite beads (SAD) for biodegradation of crude oil in soil. The results showed that immobilized cells had significant advantages over free strains. At day 20, the maximum of degradation in immobilized systems came to 29.8%, significantly higher than that of free cells (p <;0.05). Moreover, SAD treatments presented greater degradation than SA treatments. At the end of experiment (day 70), SAD treatments arrived greatest degradation of 46.3% that was 3.4% higher than SA treatments. The SEM analysis demonstrated also advantages of the immobilized microstructure of SAD beads. In addition to these, the effect of initial inoculation amount on biodegradation was also investigated. At day 20, immobilized cells treatment with low concentration (1×10⁴ cfu/kg) presented higher degradation rate than free form at high inoculation concentration (1×10⁵ cfu/kg) (p <;0.05). In a conclusion, diatomite is excellent amendment for alginate beads and the use of SAD beads to immobilization indigenous microbial community for the bioremediation of crude oil-contaminated soil is a feasible and promising treatment option.