The Study On Treating Oxytetracycline Wastewater By Immobilizing White Rot Fungus

The oxytetracycline wastewater is a kind of non-degradation medical production wastewater,which is characterized by complex compositions,high concentration of organic matter,high saltyand high colority,with the increasing requirements of environmental protection,the traditional treatment process can be difficult to ensure the stability of emission standards,therefore,the research and development of new processing technology is of practical significance.White rot fungi is a species of thread shape fungus which can bring lumber to rot in recent years,studies have shown that white rot fungi can degrade variety of toxic and non-degradation organic effectively;because of the easy-to-achieve solid-liquid separation,re-use of micro-organisms and so on,immobilized microbial technology developed rapidly and applied in the treating wastewater recent years.The article aim to the treatment of oxytetracycline wastewater and studied the preparation conditions,degradating characteristics and applications of white rot fungi.The main findings of this paper are as follows:1) According to the fungus which can bring lumber to rotthe paper seleced advantage strain BFL-5 through the way of flat-line law.Mission-shaped or globular white mycelium cab be geted under the conditions of pH 4.5,temperature30℃,speedl40 r·min^-1;The dry cell weight method is applied to measure the growth of white rot fungi.2) The advantage strain BFL-5 is belong to the mucor genus according to the forms of myceliums and spores,and the 26s rDNA identification results.3) In order to improve the survival and degradation of esperimental strain in oxytetracycline wastewater,the paper domesticated the strain through gradually increase the propotion of oxytetracycline wastewater in experimental wastewater,the results shown that the domesticated strain BFL-5 is better in growth speed,degradability and can be better adapt to the oxyetracycline wastewater.4) The conditions of the immobilized using sodium alginate as carrier were studied. The optimal conditions were chosen by four design factors and three levels of orthogonal test in terms of the acid red dye decolorization rate and shape,color,strength,flexibility and other factors of ball.Experiments shown that the best conditions of the immobilized white rot fungi is: the concentration of entrapping agents sodium alginate 4%,the concentration of crosslinker CaCl₂ 4%,cross-linking of time 18 h,the concentration of fungus in liquid 10mL for each vaccination of about 5.0×10⁶ sporesembedded in this condition, immobilized white-rot fungi into the ball goodfixed-diameter ball 3 mm,milky white. strength and flexibility of the ball are good,acidic red decolorization rate can be as high as 90%,significantly higher than free white-rot fungi and activated sludge.5) In this paper,using high performance liquid chromatography to determine the content of oxytetracycline in oxytetracycline wastewater which treated by the immobilized white-rot fungi.Chromatography conditions for the mobile phase:0.1%phosphoric acid:methanol(40:60);detection wavelength 254 nm;injection volume 20μL;flows 0.7 mL·min^-1:column temperature was 35℃.Using the immobilizing white rot fungi BFL-5 to treat oxytetracycline wastewater, CODcr removal rate can be stabilized at 80%,oxytetracycline degradation rate can be as high as 95%.Studied results provide a scientific reference to further study.