机油高效降解菌群筛选及降解效果初探

Preparation and evaluation of mixed culture bacteria for degrading machine oil

从多处受石油污染的土壤中经过初步筛选、混合驯化得到以机油为唯一碳源进行生长代谢的混合菌群。利用此混合菌群进行的降解实验结果表明,该菌群对高浓度机油废水具有较强的降解能力,初始含机油约2.0g/L的人工废水,接种量为0.1%(菌体湿重/培养液体积),经过7d的降解,机油可降至403mg/L,降解率达81.4%;对不同浓度机油废水的降解实验结果表明,在静态实验条件下,机油质量浓度在不高于1000mg/L(含1075mg/L),混合菌群在降解过程中能自行从降解产酸的不良环境中恢复,机油质量浓度在2000mg/L以上,初期产酸较多,pH下降幅度较大,在7d的周期内,废水pH无法恢复,说明在降解后期仍有大量有机酸积累而未被彻底降解;与葡萄糖共基质的降解实验结果表明,经过7d的降解,不超过150mg/L的葡萄糖与1000mg/L机油组成的共基质体系中,机油降解基本不受葡萄糖加入的影响,但可加强早期的降解速率。而葡萄糖高于150mg/L时,则会对混合菌群的除油率产生抑制,抑制程度随着葡萄糖浓度的提高而加大。

Mixed culture bacteria living on machine oil as the sole carbon source was prepared from soil samples from petroleum-contaminated sites by screening and acclimation. Starting with 2 000 mg/L of machine oil and with an inoculum density of 0.1%, the bacteria removed 81.4% of oil after 7 d of biodegradation at 32 ℃. When the initial machine oil concentration was under 1 000 mg/L, degradation resumed after pH recovered from the initial decline; when the initial machine oil concentration was above 2 000 mg/L, the pH was not fully recovered resulting in less effective degradation. Starting with an oil concentration of 1 000 mg/L, the initial degradation rate was enhanced by adding a small amount of glucose （〈150 mg/L） ; however, a higher dose of glucose （〉150 mg/L） inhibited oil degradation.