Abstract: In order to achieve efficient and harmless treatment of formaldehyde, a highly efficient formaldehyde degrading bacterium WY0 was isolated and screened from the activated sludge of an aerobic tank of a sewage treatment plant in Tianjin by using formaldehyde as the only carbon source, and its growth characteristics and the effects of different culture temperature, pitching rate, pH, formaldehyde mass concentration, NaCl and additional carbon and nitrogen sources on the strain’s formaldehyde degradation were studied. The three-half-order kinetic equation was used to fit the degradation process of strain under different mass concentrations of formaldehyde. The results showed that WY0 was identified as Achromobacter marplatensis by colony morphology and molecular biology identification. The maximum specific growth rate (SGompertz model) of strain WY0 was 0.603. Under the conditions of 10% inoculation amount, temperature 25-35 ℃, pH 4-6, and NaCl mass concentration 0-30 g/L, strain WY0 could efficiently degrade formaldehyde, and could tolerate 1000 mg/L formaldehyde. The three-half-order model fitted well with the formaldehyde degradation process of the strain, R2was greater than 0.96.

Key words: Achromobacter marplatensis, formaldehyde, biodegradation, salt tolerance, dynamics