Biodegradation of melamine formaldehyde by Micrococcus sp. strain MF-1 isolated from aminoplastic wastewater effluent

Novel bacterial strain MF-1, able to grow using melamine formaldehyde (MF) resin as main carbon and nitrogen source, is described and characterized. Strain MF-1 was isolated from wastewater effluent of an aminoplastic industrial plant. Growth rate kinetics of the strain on MF showed a maximum specific growth rate (μmax) of 0.83 cells ml−1 h−1 and Ks of 7.18 cells ml−1. Mineralization of MF by strain MF-1 was confirmed by the decrease in dissolved oxygen (DO), release of ammonia, and detection of intermediate metabolites during biodegradation. Melamine, cyanuric acid, and biuret were detected as intermediate metabolites in the culture filtrate, suggesting that biodegradation of MF by strain MF-1 proceeds via successive deamination reactions of melamine to cyanuric acid, which is hydrolyzed to biuret and finally to NH3 and CO2. Based on 16S-rDNA sequence analysis, strain MF-1 had a similarity of 97% to Micrococcus sp. MN 8.1d. However, the high bootstrap value obtained in the phylogenetic analyses suggests that this is a novel strain.