3株低温烷烃降解菌的摄取模式

Uptake Modes on Three Types of Low Temperature Alkanes-Degrading Microbes

采用碳源利用性、细胞表面亲油性和发酵液乳化性方法研究了3株低温烷烃降解菌:A(耶氏酵母菌)、H(红球菌)及LD2(不动杆菌)对石油烃的摄取模式。结果表明,A、H菌利用亲水性碳源能力较强,稳定期发酵液OD600值分别为1.85～2.12、1.41～1.54,同时菌株能较好的利用疏水性碳源生长,发酵液OD600值分别为0.68～0.80、0.63～0.68;菌株细胞表面亲油性在对数生长期最高,MATH值分别为0.69、0.61;菌株均产生表面活性物质,使油层乳化呈微滴悬浮于水相,乳化层与总高度比值最大分别为0.94、0.96;确定A、H菌摄取石油烃时属于细胞与石油烃微滴之间的相互作用模型。LD2菌利用亲水性碳源能力较差,稳定期发酵液OD600值仅为0.48～0.58,但能较好的利用疏水性碳源生长,发酵液OD600值为0.78～0.82;菌株细胞表面亲油性在整个生长周期均较高,MATH值为0.72～0.85;油层无乳化;确定LD2菌在摄取石油烃时属于细胞与石油烃大颗粒之间的直接接触模型。

Carbon energy utilization,cell surface hydrophobicity and broth emulsion capability methods were adopted to study uptake modes on three types of low temperature alkanes-degrading microbes,A（Yarrowia sp.）,H（Rhodococcus sp.）,LD2（Acinetobacter sp.）to assimilate petroleum hydrocarbon.The results show that microbe A and H exhibited good capability to utilize hydrophilic carbon energy,broth OD600 values are 1.85～2.12 and 1.41～1.54 respectively at stale period,and microbes also utilized hydrophobic carbon energy well,broth OD600 values are 0.68～0.80 and 0.63～0.68.Microbe cell surface hydrophobicity reached maximum values at logarithmic growth phase,MATH values are 0.69 and 0.61.Microbes can produce surfactant to make oil layer emulsion and presented large amount of microdroplets suspended in water phase,the maximum height ratio of emulsion layer to total layers are 0.94 and 0.96,so uptake mode on microbe A and H belong to interaction between cell and petroleum microdroplets.Microbe LD2 has poor capability to utilize hydrophilic carbon energy,broth OD600 values are only 0.48～0.58 at stable period,but LD2 utilized hydrophobic carbon energy well,broth OD600 values are 0.78～0.82.Microbe had a higher cell surface hydrophobicity at all growth periods,MATH values are 0.72~0.85,oil layer demonstrated none emulsion,therefore,uptake mode on microbe LD2 belongs to direct contact between cell and petroleum large particles.