Biodegradation of Crude Oil in Contaminated Soils by Free and Immobilized Microorganisms

• Published in: Pedosphere Vol. 22; no. 5; pp. 717 - 725
• Main Authors: WANG, Zhen-Yu, XU, Ying, WANG, Hao-Yun, ZHAO, Jian, GAO, Dong-Mei, LI, Feng-Min, XING, B.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2012; Department of Plant, Soil and insect Sciences, University of Massachusetts, Amherst MA 01003(USA); College of Animal Science and Veterinary Medicine, Qingdao Agricultural University, Qingdao 266109(China)%Chemical and Mineral Metal Material Testing Center, Tianjin Entry-Exit Inspection and Quarantine Bureau, Tianjin 300456(China)%College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100(China); College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100(China)%College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100(China)
• Subjects: bacterial growth; degradation rate; hydrocarbon degraders; immobilized cells; sodium alginate-diatomite beads; 原油污染; 固定化微生物; 扫描电子显微镜; 污染土壤; 游离细胞; 生物降解; 细胞固定; 黄河三角洲地区; China, People's Rep., Huang He R; degradation rate; bacterial growth; hydrocarbon degraders; sodium alginate-diatomite beads; immobilized cells
• ISSN: 1002-0160; 2210-5107
• DOI: 10.1016/S1002-0160(12)60057-5

The efficiencies of free and immobilized bacterial cultures of petroleum hydrocarbon degraders were evaluated and compared in this study. Hydrocarbon-degrading microbial communities with high tolerance to and high degrading ability of crude oil were obtained from the soil contaminated with crude oil in the Yellow River Delta. Then, the microbial cells were immobilized in sodium alginate （SA） beads and sodium Mginate-diatomite （SAD） beads. The biodegradation of crude oil in soil by immobilized cells was compared with that by free cells at three inoculation concentrations, 1× 104 colony forming units （cfu） kg-^（-1）（low concentration, L）, 5 × 104 cfu kg^（-1） （medium concentration, M）, and 1× 105 cfu kg^（-1） （high concentration, H）. At 20 d after inoculation, the maximum degradation rate in the immobilized systems reached 29.8% （SAD-M）, significantly higher （P 〈 0.05） than that of the free cells （21.1%）, and the SAD beads showed greater degradation than the SA beads. Moreover, both microbial populations and total microbial activity reached significantly higher level （P 〈 0.05） in the immobilized systems than free cell systems at a same initial inoculation amount. The scanning electronic microscope （SEM） images also confirmed the advantages of the immobilized microstructure of SAD beads. The enhanced degradation and bacterial growth in the SAD beads indicated the high potential of SAD beads as an effective option for bioremediation of crude oil-contaminated soils in the Yellow River Delta.