Decolorization Of Molasses Alcohol Wastewater And Analysis Of Microbial Community Structure

Molasses alcohol wastewater belongs to high concentration organic wastewater with higher levels of pigment, mainly composed of phenolic pigments melanoidins caramel. The main component of the pigments are phenolic compounds and amino nitrogen compounds. The antioxidant properties of pigments makes decolorization as a difficulty in molasses wastewater treatment. Study of decolorization of molasses alcohol wastewater by microorganisms is on a late start, and efficiency needs to be improved.In this study, using different concentrations of wastewater as the sole carbon and nitrogen sources, we enriched the activated sludge taken from the bottom of IC reactor treating molasses alcohol wastewater and wastewater from bagasse spraying in a sugar factory and got a microbial community which exhibited24%decolorization and19.2%COD reduction under30℃with10%(v/v) wastwater. In order to improve the efficiency of decolorization, some factors such as wastewater concentration, different components of the wastewater, pH, temperature, incubation time had been considered for the effect on microorganisms’growth, decolorization rate and COD removal ability. The results showed that the highest decolorization yield of46.2%and38.5%COD reduction when cultivated at37℃for7days in10%(v/v)wastewater containing0.5%glucose,0.1%yeast extract,0.1%KH2PO4,0.05%MgSO4·7H2O,0.05%KCl and the pH adjusted to7.0.In the order of understanding the microbial community structure envolving in the treatment of molasses alcohol wastewater, bacterial16S rDNA clone library was constructed, and the representative clones were sequenced. The results was that bacterial was mainly distributed in Erysipelotrichales, Clostridiales, Lactobacillales, Xanthomonadales, Burkholderiales, Enterobacteriales, Bacteroidales of Firmicutes, Proteobacteria, Bacteroidetes. Most of the bacteria belong to fermented bacteria, of heterotrophic type. Combined with DGGE technique, bacterial and archaeal propotion and diversity before and after optimizing were analyzed. The results showed that compared with the activated sludge before inoculated, after optimization, the content of Bacteroidales decreased, but Clostridiales, Enterobacteriales, Burkholderiales increased. Dominant groups in archaea changed from Methanosarcinales and Methanomicrobiales to Thermoplasmatales. The experimental results provided a basis for the use of microbial control of molasses alcohol wastewater in biological decolorization.