Effects of Oil Contamination Levels and Microbial Size on Hydrocarbon Biodegradation.

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 $CO_2$ per g of soil, respectively. The degradation rate constant (k) of TPH was decreased in proportion to the initial oil concentrations while $CO_2$ 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 $3${\times}$10^{6}$ , $5${\times}$10^{7}$ , $2${\times}$10^{8}$ 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.

원유오염농도와 미생물 농도가 탄화수소의 생분해에 미치는 영향

오염토양에 유류분해능을 가진 Nocardia sp. H17-1의 접종시 고려되어야 할 인자중 하나인 초기 오염농도에 의한 탄화수소분해능과 초기 접종농도에 의한 분해능 및 균주의 생육을 조사하였다. H17-1은 실험 50일 동안 초기 오염농도 10, 50, 100 g Arabian light oil/kg of soil에 대해 각각 78.5%, 94.3%, 53.2%의 탄화수소를 제거하였으며, 오염농도가 높을수록 분해속도 상수(k) 낮아졌다. $CO_2$의 생성량 또한 오염농도가 높을수록 증가하였으나, 100 g/kg-soil의 오염농도에서는 균의 생육이 저해를 받는 것으로 나타났다. H17-1의 초기 접종농도에 의한 영향은 균의 접종량에 따라 최종 남은 TPH의 양은 큰 차이를 나타내지 않았으나, 분해속도상수(k)는 균의 접종량이 늘어남에 따라 크게 증가되었으며, $CO_2$의 생성량 또한 균의 접종농도에 따라 증가하였다.