Biological Degradation and Transformation Characteristics of Total Petroleum Hydrocarbons by Oil Degradation Bacteria Adsorbed on Modified Straw.

Abstract

We report a simple and “green” method for the fabrication of polymer-modified straw-supported oil degradation bacteria (PMS-ODB) for biological degradation of total petroleum hydrocarbons (TPHs) in water. The modification of straw was achieved by in situ copolymerization of styrene and butyl methacrylate using methylene-bis-acrylamide as a cross-linker in an aqueous solution containing straw powders. Compared with the control group (ODB loaded on untreated straw), the results obtained from the experimental group show that the polymer-modified straw is beneficial to the growth of microorganisms. As a result, the degradation rate of TPHs reaches 90.12%, which is 50.54 and 7.08% higher than that of the blank group (ODB only) and the control group, respectively. A study on the transformation characteristics of PMS-ODB shows that the degradation rate of alkanes with low, medium, and high carbon number is higher than 90%. w(∑C21–)/w(∑C22+) (the mass ratio of normal alkanes of high carbon/low carbon), w(pr)/w(ph) (the ratio of pristane/phytane), and OEP (the mass ratio of normal alkanes of odd carbon/even carbon) for TPHs in the experimental group were measured to be 0.6186, 0.7248, and 1.4356, respectively, all of which are the largest value among the blank group, control group, and experimental group. These findings indicate that compared with the control group, the modification of straw could enhance the comprehensive biological degradation performance for TPHs, even those highly stable organics, such as carbon n-alkanes and isoprenoid hydrocarbon, which may open a new possibility for degradation of oils or toxic organics in an enhanced biological manner.