多环芳烃降解真菌Fusarium solani对芘的吸收存储和降解特性研究

以芘为唯一碳源,从公路旁污染土壤中分离得到一株芘降解真菌,经鉴定为Fusarium solani(命名为Py F-1),荧光显微镜观察发现其菌丝能吸收储存芘.对该菌株在芘浓度为50 mg·L-1的液体培养基中对芘的吸收储存和降解特性,具体包括芘的生物降解、菌体吸收、菌体吸附和消解总量进行了39 d的动态研究,结果表明:生物降解芘在培养0~14 d内逐渐增加,培养14 d时占芘添加量的15.9%,此后基本达到稳定,培养结束时生物降解芘为芘添加量的17.6%;菌体吸收芘在0~21 d内含量较少且变化不显著,低于芘添加量的3%;而在21~39 d内,菌体吸收芘变化显著,芘的消解总量随着菌体吸收量的变化产生显著波动;培养28 d时,芘的消解总量达到最大值,其中菌体吸收芘占芘消解总量的一半,达到芘添加量的16.0%,菌体吸附芘不足芘添加量的0.5%,在研究中可以忽略不计.因此,培养前期培养基中芘的消解以生物降解为主,培养后期菌体吸收芘的变化是芘消解总量变化的主要原因.

Sorption and biodegradation characteristics of pyrene by a PAH degradation fungus Fusarium solani

A pyrene degradation fungus was isolated from roadside soil and was identified as Fusarium solani species (named PyF-1). Pyrene can be absorbed and stored in the hyphae based on the examination of PyF-1 under a fluorescence microscope. Hence, sorption and biodegradation characteristics, which include the kinetic characteristics of the biodegradation, absorption, adsorption and dissipation of pyrene by PyF-1, were studied in liquid cultures containing 50 mg·L^-1 of pyrene over 39 days. Pyrene degradation by PyF-1 increased gradually over the first 14 days and then stabilized to the end of experiments. The percentages of pyrene degraded by PyF-1 were 15.9% and 17.6% of the initial added pyrene at 14 days and 39 days, respectively. During the period of 0~21 days, there was no significant variation of pyrene absorbed by PyF-1 and the amount was less than 3% of the initial added pyrene. However, pyrene absorbed by PyF-1 varied dramatically in the period of 21~39 days, which also caused dramatic variation of the total amount of dissipated pyrene. The amount of pyrene absorbed by PyF-1 reached the maximum value of 16.0% of the initial added pyrene, which accounted for half of the total dissipated pyrene in 28 days. Pyrene adsorption on Fusarium solani hyphae was less than 0.5% of initial added pyrene and its contribution to the total dissipated pyrene can be neglected in this study. The results indicated that during the earlier stage of incubation, dissipated pyrene was largely biodegraded by Fusarium solani, whereas the variation of pyrene absorbed by Fusarium solani were the main factor for the variation of dissipated pyrene in later period of incubation.