Effects of oil contamination levels and microbial size on hydrocarbon biodegradation = 원유오염농도와 미생물 농도가 탄화수소의 생분해에 미치는 영향

Abstract

The purpose of this study was to evaluate the influence of oil concentration and inoculum size on petroleum biodegradation in soil by Nocardia sp. H17-1, isolated from oil-contaminated soil. To investigate the effect of initial oil concentration on total petroleum hydrocarbon (TPH) degradation, the soil was artificially contaminated with 10, 50 or 100 g of Arabian light oil per kg of soil, respectively. After 50 days, Nocardia sp. H17-1 degraded 78, 94 and 53% of the each initial TPH concentration, respectively. Also, it produced 1.35, 4.21, and 5.91 mmol of CO2 per g of soil, respectively. The degradation rate constant (k) of TPH was decreased in proportion to the initial oil concentrations while CO2 production was increased with the concentration. The growth of Nocardia sp. H17-1 was remarkably inhibited when it was inoculated into soil containing 100 g of oil per kg of soil. To evaluate the effect of the inoculum size, the soil was artificially contaminated with 50 g of Arabian light oil per kg of soil, and inoculated with 3×10 6, 5×107, 2×108 cells per g of soil, respectively. After 50 days, the degradation of TPH was remained with similar in all treatment but degradation rate constant (k) and evolved CO 2 was increased with increasing the inoculum size.