Decoloration Of Dye By Co-culturing System Of Microorganisms

Recently, with the rapid development of textile industry, the variety and quantity of dyes were increasing, so the printing and dyeing wastewater became one of the polluting sources of water environment. The conventional physical-chemical methods had hereinafter disadvantages: the dissatisfied disposal effect, the high expenditure and the confined applied range. So the biologic method was received much account.This paper screened 24 strains including 13 bactria and 11 fungi, then the inhibitory activity experiments were done between these strains, then the negative ones wereselected and mixed groups were built up. The decolorization and degradation effect and some environment conditions were compared between single stain and mixed groups, and it was further studied that the technical qualifications of the co-culturing system of fungi-bactria on mixed dyes and two kinds of practical wastewater. The result showed:Both single bactrium and mixed bactria could use various carbon sources but demanded specific nitrogen sources, sucrose and peptone were the mixed bactria's optimum carbon source and nitrogen source respectively. Compared to single bactrium ,the mixed bactria could keep high decolorization and degradation rate in broader pH and temperature range, the optimum pH was7,and optimum temperature was 35℃. With the dyes' concentration increased from 20mg/L to 160mg/L, the decolorization and degradation rate decreased, but that of the mixed bactria decreased slower than single bactrium.As same as bactria, both single fungus and mixed fungi could use various carbon sources but demanded specific nitrogen sources, the mixed fungi' optimum carbon and nitrogen sources were maltose and peptone. Different strains had different optimum pH and temperature, and the mixed fungi could decolorate dyes well in pH4-9,22-38℃, and the optimum degradation environment conditions were pH 4 and 28℃. With the dyes' concentration increased, the decolorization and degradation rate decreased, but even kept above 90% and 60% respectively when the dyes' concentration increased to 160mg/L.When fungi and bactria were inoculated simultaneously and proportion was 2:1, the co-culture system of microorganisms could decolor 98.36% and degrade 89.89% of the mixed dye after 12h, And it was showed that the co-culture system had good endurance on high dyes' concentration because the decolorization and degradation still attained 97.03% and 74.03% even if the dyes' concentration was at 320mg/L. Oxygen was availed of increasing decolorization and degradation, maybe oxygen was dependent in the course of biodegradation. At the same technics' conditions, the decolorization and degradation rate were 98.38% and 92.70% on blue dye wastewater after 12h, and 87.22% and 82.98% on red wastewater after 24h.The function on dyes of bactria was biodegradation and adsorption of fungi, so the co-culture system of fungi-bactria could adequately make respective advantage. The studies on technics' conditions would lay theoretic foundation for application at a certain extent.