Study On The Treatment Of High-concentration Chemical Fiber Esterification Wastewater By Engineering Bacteria

Effluent from chemical fiber factory has complex components including PTA, dioxane and ethylal, and it is very difficult to treat because of strong toxicity, high density. Three effective bacterial strains named 6-81(Pseudmonas putida),3RE-15 (Pseudomonas mendocina ),D-21(Acinetobacter.sp)6-81, which can separately degrade PTA, ethylal and dioxane were isolated from natural soil sample. After ultraviolet radiation, auxotrophic mutants could be created. Based on these auxotrophic mutants, a kind of new engineering bacterium which includes all characteristics of them was cultivated to treat chemical fiber wastewater through protoplast fusion.In this paper several main procedures were carried out to realize the waste water treating process: screening and identification highly active microbe; getting highly active engineering bacteria through protoplast fusion; studying on the technological conditions of wastewater treatment. Experiments and researches resulted in some conclusion as follow:1. A strain of bacterium D-21 which can degrade dioxane with high efficiency was screened out by enrichment, isolation and purification. According to the"Bergey's Manual of Systematic Bacteriology"(the eighth edition), D-21 was identified preliminarily as Acinetobacter.sp based on its phenotypic characteristics, physiological and biochemical characteristics.2. Three kinds of auxotrophic mutants were created as the mark of protoplast fusion through mutagenesis: D-21 is aspartate auxotroph, 6-81 is methionine auxotroph, 3RE-15 is tryptophane auxotroph. Then after orthogonal experiment, these three bacteria's optimally conditions of protoplast preparation and reproduction were obtained. Finally the excellent fusant named 3-1, which can degrade three compounds in wastewater at the same time and can maintain stable heredity, was obtained.3. Firstly, optimal technological conditions of engineering bacteria and highly active compositing bacteria were determined by orthogonal experiment. Then Monod equation would definite vmax and Km to evaluate the degrading rate of chemical fiber wastewater by engineering bacteria. According to Monod equation, degradation dynamics equation of engineering bacteria and high effective bacteria can be separately expressed as follow: degradation dynamics equation of engineering bacteria: v=0.3480×S/(134.0148+S), degradation dynamics equation of high effective bacteria: v=0.2600×S/(119.8793+S). vmax of engineering bacteria is 0.3480d-1, and Km of engineering bacteria is 134.0148 mg/L.