Biodegradation of tetracycline by Cladosporium colombiae T1: performance and degradative pathway

The microbial degradation of tetracycline (TC) represents an effective bioremediation method. An effective TC-degrading strain of Cladosporium colombiae T1 was isolated from chicken manure using enrichment techniques. Response surface methodology was employed to ascertain the optimal conditions for removing TC by strain T1, identified as a temperature of 40.00 °C, solution pH of 6.92, TC concentration of 42.99 mg/L, and inoculum dose of 1.98%. The inhibitory effect of TC degradation products on Escherichia coli was investigated using the paper diffusion method. The results demonstrated that the toxicity of TC degradation products by T1 was lower than that of the parent compound. The shake-flask batch experiments showed that the biodegradation of TC was a synergistic effect of intra- and extracellular enzymes, with intracellular enzymes exhibiting greater efficacy in TC degradation (48.56%). LC-MS analysis identified ten potential biodegradation products, and biodegradation pathways were proposed. This study offers a theoretical foundation for the characterization and mechanistic investigation of TC degradation in the environment by Cladosporium colombiae T1.