Screening of Formaldehyde-degrading Bacteria and Their Degradation Effects

Purpose To screen bacterial strains that can efficiently degrade formaldehyde, providing support for biological remediation of formaldehyde pollution.

Methods Through primary and secondary screening of endophytic bacteria isolated from mangrove plants, strains with high efficiency of formaldehyde degradation were selected preferentially, and their physiological and biochemical indices were determined, and 16S rDNA was identified. The application potential was evaluated by measuring their formaldehyde degradation ability.

Results A total of three strains of endophytic bacteria with high efficiency of formaldehyde degradation were screened out: Bacillus haynesii (BQB-A17), Enterobacter ludwigii (ZTB-A30), and Brucella intermedia (BQB-B02). All three bacterial strains were Gram-positive, and the catalase test was negative; Voges-Proskauer (V-P) test, glucose gas production, starch hydrolysis, and indole tests of them were negative; only strain ZTB-A30 showed positive results in methyl red test and glucose acid production test; and the citrate utilization, nitrate reduction, malonate utilization, and H₂S production tests were all positive. In laboratory shake-flask experiments, all three strains exhibited formaldehyde degradation rates exceeding 80%. In the accident pool storage tank of the biochemical plant sewage treatment station, the formaldehyde degradation rates of strains BQB-A17, ZTB-A30, and BQB-B02 reached 86.35%, 83.76%, and 83.42% at six hours, respectively, and further increased to 92.68%, 90.98%, and 90.11% at 12 hours, respectively.

Conclusion In this study, three strains of endophytic bacteria with formaldehyde degradation ability were screened out, which broaden the selection range of formaldehyde-degrading bacteria and enrich the types of formaldehyde-degrading bacteria, providing a theoretical basis and technical support for microbial degradation of formaldehyde.