Petroleum pollution is a major concern in Antarctica due to the persistent nature of its hydrocarbon components coupled with the region’s extreme environmental conditions, which means that bioremediation approaches are largely inapplicable at present. The current study assessed the ability of the psychrotolerant phenol-degrader, Rhodococcus sp. strain AQ5-07, to assimilate diesel fuel as the sole carbon source. Factors expected to influence the efficiency of diesel degradation, including the initial hydrocarbon concentration, nitrogen source concentration and type, temperature, pH and salinity were studied. Strain AQ5-07 displayed optimal cell growth and biodegradation activity at 1% v/v initial diesel concentration, 1 g/L NH₄Cl concentration, pH 7 and 1% NaCl during one-factor-at-a-time (OFAT) analyses. Strain AQ5-07 was psychrotolerant based on its optimum growth temperature being near 20 °C. In conventionally optimised media, strain AQ5-07 showed total petroleum hydrocarbons (TPH) mineralisation of 75.83%. However, the optimised condition for TPH mineralisation predicted through statistical response surface methodology (RSM) enhanced the reduction to 90.39% within a 2 days incubation. Our preliminary data support strain AQ5-07 being a potential candidate for real-field soil bioremediation by specifically adopting sludge-phase bioreactor system in chronically cold environments such as Antarctica. The study also confirmed the utility of RSM in medium optimisation.

中文翻译：

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统计优化的南极细菌，红球菌生长条件和柴油降解。菌株AQ507

由于其碳氢化合物成分的持久性以及该地区的极端环境条件，石油污染成为南极关注的主要问题，这意味着生物修复方法目前在很大程度上不适用。目前的研究评估了抗精神病药苯酚降解菌红球菌（Rhodococcus sp。）的能力。品系AQ5-07，可以吸收柴油作为唯一的碳源。研究了预期影响柴油降解效率的因素，包括初始烃浓度，氮源浓度和类型，温度，pH和盐度。菌株AQ5-07在1％v / v初始柴油浓度，1 g / L NH _4下显示最佳的细胞生长和生物降解活性一次一因素分析（OFAT）中的Cl浓度，pH 7和1％NaCl。基于其最佳生长温度接近20°C，AQ5-07菌株具有抗精神病能力。在常规优化的培养基中，菌株AQ5-07显示总石油烃（TPH）矿化率为75.83％。但是，通过统计响应面方法（RSM）预测的TPH矿化的最佳条件将其在2天的培养时间内降低了90.39％。我们的初步数据支持菌株AQ5-07通过在南极州等长期寒冷的环境中特别采用污泥相生物反应器系统，有望成为实地土壤生物修复的潜在候选者。该研究还证实了RSM在中等优化中的实用性。