摘要
从青海油田附近被石油污染的土壤中分离得到一株可利用原油为唯一碳源的菌株,将其命名为X4菌株。经16SrDNA分析鉴定,该菌株与中度嗜盐菌Salinicola zeshunii strain N4~T(GenBank序列号为EU056581)同源性高达99%。X4菌株的最适温度为30℃,最适盐度为8%,最适pH为6.5,最佳碳源为甘油,最佳氮源为氯化铵。该菌可产生生物乳化剂,具有较强的细胞疏水性,对正辛烷、十六烷、二甲苯等典型烃类物质具有良好的乳化能力,细胞CSH值达到60%以上。在含5%盐度的无机盐培养基中,以3g/L的柴油为唯一碳源,采用GC-MS定量分析X4菌株的烃降解特征,结果表明菌株X4培养5天后柴油的总降解率达56%,菌株X4优先降解中长链烃类;C_7～C_(13)烃类的平均降解率为64.1%,C_(14)～C_(20)烃类的平均降解率为52.3%,C_(21)～C_(31)烃类的平均降解率约26.8%。离子型表面活性剂TTAB和SDS对X4菌株生长具有较强的毒性:在浓度达到100mg/L和400mg/L时能完全抑制菌体生长;在40mg/L的浓度下,使得菌株对柴油的降解率降低到20%。而X4菌株对非离子型表活剂——吐温80和生物表面活性剂——鼠李糖脂的耐受浓度均可达400mg/L。鼠李糖脂是嗜盐菌X4菌株的合适复配表活剂。
A crude oil resistant strain X4 was isolated from oil contaminated soil near Qinghai oilfield. It was identified as Salinicola sp. and named as Salinicola sp. X4, since the 16 Sr DNA sequencing homologie to Salinicola zeshunii strain N4T(GenBank serial number EU056581) was up to 99%. The optimal temperature, NaCl concentration, pH, carbon source and nitrogen source of Salinicola sp. X4 was 30℃, 8%, 6.5, glycerol and NH4Cl, respectively. The bacterium could produce bioemulsifier, and it had good emulsification ability toward some typical hydrocarbons such as octane, cetane, xylene. The CSH values of Salinicola sp. X4 could reach 60%. Using diesel oil(3 g/L) as the sole carbon source in the inorganic salt medium containing 5% NaCl, the Salinicola sp. X4 could degrade 55% of the total diesel for five days. GC-MS analysis showed that the strain preferred to degrade medium-chain length hydrocarbons firstly;the average degradation rate of C7―C13, C14―C20, C21―C31 was 64.1%, 52.3% and 26.8%, respectively. The ionic surfactant SDS and TTAB had strong toxicity to the cells: strain X4 wasn’t able to survive when the concentration reached 100 mg/L and 400 mg/L, respectively;under the concentration of 40 mg/L, the degradation rate of diesel oil was reduced to 20%. While the tolerance concentration of the strain to the non-ionic surfactants――Twain80 and bio-surfactant――rhamnolipid reached 400 mg/L;and rhamnolipid is a suitable compound surfactant for strain X4.
作者
林佳辉
王丹
李霜
LIN Jiahui;WANG Dan;LI Shuang(College of Biotechnology and Pharmaceutical Engineering,Nanjing Tech University,Nanjing 210009,Jiangsu,China)
出处
《化工进展》
EI
CAS
CSCD
北大核心
2019年第4期1894-1902,共9页
Chemical Industry and Engineering Progress
基金
国家自然科学基金(51774188)
江苏省先进生物制造协同创新中心项目(XTD1824)
关键词
中度嗜盐菌
降解
柴油
表面活性剂
moderately halophilic bacterium
alkanes degradation
diesel oil
surfactant
