Abstract:Symbiotic bacteria were isolated and purified from the Ochromonas sp. culture system. It was proposed to improve the capacity of microalgae biomass accumulation through the establishment of algae-bacteria symbiosis system. And the treatment effect of the algae-bacteria symbiosis system on papermaking wastewater was explored. Five strains of bacteria were identified as Porphyrobacter sp. (A), Hygromonas sp. (B), Aquimonas sp. (C), Agrobacterium sp. (D) and Hydrophaga sp. (E) by 16S rDNA sequencing technology. In order to verify the effect on the growth efficiency of microalgae, different bacteria were added to the culture system of microalgae. The results showed that Aquimonas sp. could significantly promote the growth of Ochromonas sp. among the five bacterial strains. And the best growth-promoting effect was showed when the algae/bacteria ratio was 1:3. The dry weight of Ochromonas sp. increased to 0.78 g/L on the 10th day of cultivation. The wastewater was treated by symbiotic system in 8 days, the concentration of COD, TN , TP and chroma could be reduced from 153.45 mg/L, 31.58 mg/L , 4.83 mg/L and 275 to 37.5 mg/L, 20.53 mg/L , 0.48 mg/L and 18, with the removal rates of 75.67%, 35.19% , 90.2% and 93.45% respectively. At the same time, the content of dry weight in microalgae was 1.073 g/L. The effect of microalgae-bacteria symbiosis system on the advanced treatment of papermaking wastewater is similar to Fenton Method and with lower cost, which can meet the Pulp and Paper Industry Water Pollution Discharge Standard (GB3544-2008) and have wide perspective on the treatment of wastewater.