Biodegradation of 5α-dihydrotestosterone to non-androgenic products

• We performed a method to screen microbes for dihydrotestosterone degradation.
• A bioluminescent androgen bioassay (BLYAS) was adapted to biodegradation tests.
• The most appropriate microbe with the least harmful biological effects was selected.
• We demonstrated the necessity of employing bioassays in biodegradation tests.

The aim of this study was to screen microorganisms belonging to Rhodococcus and Cupriavidus genera, for their DHT degrading capability and to select microbes with the best biodetoxification potential. Bioluminescent bioreporters (Saccharomyces cerevisiae BLYAS and BLYR) were successfully used to monitor DHT degradation and the results were confirmed by chemical analysis (GC–MS). Several strains with high potential for DHT biotransformation were selected on the base of analytical method, but bioreporters were able to monitor the samples for bioavailable toxicants and androgenic potential even after substantial degradation. Based on this integrated chemical and biological analysis DHT-degrading microbes, ones that produced minimal toxic products and products with lower androgenic potential could be selected. Out of the selected microbes Rhodococcus pyridinivorans strain AK37 was further investigated by using extracellular extracts of the microbe, which demonstrated a DHT-degradation with the total loss of androgenicity after 9 h. Results indicated that the degradation is enzymatic and that the enzymes responsible for the degradation of DHT are extracellular and constitutively produced.