Isolation and Characterization of Bacillus sp. BZ-001H Capable of Biodegrading Formaldehyde at High Concentration

A formaldehyde-degrading bacterium named BZ-001H was isolated from activated sludge while searching for an efficient strain of bacteria for bioaugmentation during treatment of high-concentration formaldehyde wastewater. It was identified as Bacillus sp. by cell and colony morphologies, biochemical properties, and 16S rDNA sequence analysis. Further study showed that BZ-001H retained its activity with respect to formaldehyde degradation when the pH range was 5–10, temperature range was 5–45°C, and initial formaldehyde concentration was 4,000–20,000 mg/L. BZ-001H exhibited highest removal efficiency and growth rate at pH 7, temperature of 30°C, and 8,000 mg/L of formaldehyde. Moreover, formic acid and methanol were intermediate products. In addition, formaldehyde removal rate was slightly effected by initial substrate concentration, but it was decreased with impact of formaldehyde concentration and intermediate products in the early 9 h. This bacterium might reveal potential with regard to biological formaldehyde treatment in real formaldehyde wastewater due to its strong tolerance to various physicochemical conditions. Overall, this article enriched the study of the biodegradation of high concentration of toxic and refractory organic substrate.