双效工程菌BBb对炼化油泥中总石油烃的降解特性

Degradation characteristics of total petroleum hydrocarbons in refining sludge by dual-function bacteria BBb

从大庆油田的含油污泥中筛选出一株既分泌表面活性物质又能降解总石油烃(TPH)的菌株(命名为双效工程菌BBb),并将其应用于炼化油泥的降解试验,考察了pH、盐度和接菌量对菌株降解TPH的影响。通过生理生化特性、扫描电镜表征和16S rDNA鉴定,确认菌株BBb呈卵圆形,为革兰氏阳性菌,属于芽孢杆菌。当pH=5、盐度为1.66%、接菌量为3%时,菌株对TPH的降解效果最佳,TPH含量由193.00 g·kg^(−1)被降解至49.18 g·kg^(−1),降解率为74.52%,降解速率为0.0959 d^(−1);BBb菌降解TPH遵循准一级动力学方程Ct=193e−0.0959t;在BBb菌降解炼化油泥过程中,菌株BBb分泌表面活性物质(LAS)浓度由初始的0 mg·L^(−1)增加至6.86 mg·L^(−1),油泥中的TPH被同步降解了143.82 g·kg^(−1)、降解率提高了67.52%,表明BBb分泌的表面活性物质提升了对炼化油泥的破乳,促进了对TPH的摄取,提高了对TPH的降解。在温度30—35℃、pH=5、盐度1.66%、接菌量3%、发酵15 d的试验条件下,BBb菌对C10—C14、C16—C28、C30—C40的平均降解率分别为38%、66%、27%;初步推测TPH分子被BBb菌摄取、吸收,部分高碳链烷烃被BBb分解为较低碳链烷烃。

A dual-function strain(BBb)that secretes surface-active substances and degrades total petroleum hydrocarbons(TPH)is isolated from the oil-bearing sludge of Daqing Oilfield,and applied to the degradation of refining sludge.The effects of pH,salinity and inoculation volume on the degradation of TPH by BBb bacteria were investigated.Through the physiological and biochemical characteristics,scanning electron microscope and 16S rDNA identification,it was confirmed that the strain BBb was oval and gram-positive,belonging to Bacillus.When pH,salinity and inoculation volume was 5,1.66%,3%,respectively,the BBb strain had the best degradation effect on TPH.The content of TPH in refining sludge was degraded from 193.00 g·kg^(−1)to 49.18 g·kg^(−1),and the degradation rate of TPH by BBb could reach 74.52%.The degradation efficiency was 0.0959 d^(−1),which followed the first-order kinetic equation.In the process of degradation of refining sludge by BBb bacteria,the concentration of surface active substance(LAS),being secreted by double-acting engineering strain BBb,increased from the initial 0 mg·L^(−1)to 6.86 mg·L^(−1).The TPH content in sludge was degraded by 143.82 g·kg^(−1)simultaneously.The degradation rate of TPH increased by 67.52%.It showed that the surface active substance secreted by BBb enhances demulsification characteristics of BBb for refining sludge.It promoted uptake of BBb for TPH,and the degradation rate of TPH by BBb was improved.When the temperature,pH,salinity and inoculation amount was 30—35℃,5,1.66%,3%,the average degradation rates of BBb bacteria for C10—C14,C16—C28,and C30—C40 were 38%,66%,27%,respectively.It was presumed that the molecule of TPH was taken up and absorbed by BBb bacteria,and some high-carbon paraffins were decomposed into lower-carbon paraffins by BBb.