Innovating Experimental Teaching System and Improving Students’ Practicing Ability——Experimental Teaching Reformation of Environmental Microbiology / 微生物学通报

A new experiment curriculum system of environmental microbiology was established centering on applied microbiology in environmental protection field and emphasizing on design and research experi- ments to motivate the students’ interests for the course, which helped them to improve their ability of think- ing independently and creatively as well as their practicing ability.

Studies on Stability of Microbial Flocculant and Its Application to Municipal Thickened Sludge Dewatering / 微生物学通报

The stability of microbial flocculant (MBF) produced by Aspergillus sojae and its application to municipal thickened sludge dewatering were studied. The results showed that the MBF had high heat and acid-base endurance with high flocculating activity in a wide range of pH from 1.5 to 12. The MBF retained 96% of flocculating activity after 35 days preservation at 4℃, but in different pH the flocculating activity difference was very apparent after 35 days store at room temperature. The experimental results also demon- strated that the MBF was better than PAM and PAC in reducing specific resistance filtration. The optimal dose of MBF used for intensifying thickened sludge dewatering is 7%(volume fraction). And the more the volume of sludge is treated, the less the cost of MBF for unit volume sludge treatment.

Isolation and Characteristics of Biosurfactant-producing Microorganism / 微生物学通报

A biosurfactant-producing strain(S_6)was isolated from oil-containing wastewater in oxidation ditch and identified as Pseudomonas aeruginosa based on physiological and biochemical experiments and 16S rDNA sequence analysis.Infrared spectrum analysis revealed that S_6 produced glucolipid in the process of metabolism.It was observed that S_6 decreased the surface tension of water from 72 mN/m to 33.9 mN/m with the critical micelle concentration(CMC)of 50mg/L.The measurement of oil displacement and surface tension demonstrated that the fermented liquid had stable surface activity at varying range of salinity,pH,amount of dissolved oxygen.The optimal culture condition was obtained through orthogonal experiment:glucose 10g/L,urea 5g/L,KH_2PO_4 1g/L,liquor of microelement 2mL,pH 8.0,water 1000mL;and the biosurfactant production under optimal culture condition was 0.173g/L.