烷烃降解菌的筛选及其降解能力

Screening of alkane degrading bacterium strains and their degradation capability

以正十二烷、正十五烷和正十六烷为唯一碳源,从腈纶废水及其处理构筑物的生物膜中,分离、筛选出两株高效降解正烷烃的菌株C-14-1和C-14-2.经形态学观察和生理生化特征研究,两者均鉴定为诺卡氏菌(Nocardia spp.).通过摇瓶试验得出两菌株的最适生长条件为35℃,pH6,摇床转速(间接反映通气量)为250r/min,接种量为0.1%.在最适生长条件下,分别对不同初始浓度烷烃进行降解率试验.结果表明,两菌株降解正烷烃的能力显著,当混合烷烃中各烷烃的初始浓度约为50mg/L时,培养11h对正十二烷、正十五烷和正十六烷的降解率达到93%~100%;各烷烃的初始浓度约为100mg/L时,培养22h降解率达到97%~100%;各烷烃的初始浓度约为150mg/L时,培养22h降解率达到85%~93%.这两菌株在实际工程中将具有较好的应用前景.

Using n-dodecane, n-pentadecane and n-hexadecane as the sole carbon source, two bacteria strains (C-14-1 and C-14-2), which have high degrading capacity for n-alkanes, are isolated and screened out from acrylic fiber wastewater and biofilm in its treatment structures. Through morphological observation and character studies of physiology and biochemistry, both two strains are identified as Nocardia spp.. By tests in shaking flasks, it is determined that the conditions of growth for these two strains are 35℃, pH6 with shaker rotary speed (which indirectly reflects aeration capacity) 250r/min, and inoculum amount 0.1%. Under these conditions for optimum growth, the degradation rate experiments on different initial concentrations of alkanes are carried out. The results indicate that the ability of these two strains for degrading n-alkanes is marked. With the initial concentration of individual compound in the alkanes mixture at about 50mg/L, the degrading rates of n-dodecane, n-pentadecane and n-hexadecane reach 93%~100% after 11h cultivation; with the initial concentration at ablut 100mg/L, the degrading rates reach 97%~100% after 22h cultivation; and with the initial concentration at about 150mg/L, the degrading rates reach 85%~93% after 22h cultivation. These two strains possess good application prospect in actual engineering.