Adaptive responses and metabolic strategies of Novosphingobium sp. ES2-1-17β-estradiol analyzed through integration of genomic and proteomic approaches

Environmental 17 beta-estradiol (E2) can cause potential harm to ecological balance and human health. Novosphingobium sp. ES2-1 is an E2-degrading bacterium previously obtained, which converts E2 to estrone (E1) and then to 4-hydroxyestrone (4-OH-E1) followed by oxidation to form metabolites with long-chain structure during upstream degradation. Herein, we found that intracellular enzymes were the major contributors to E2 biodegradation by strain ES2-1. A total of 243 proteins were dys-expressed under E2 condition, 123 were up-regulated and 120 were down-regulated thereinto. The up-regulated members of ABC transport systems, aromatics degradation, and fatty acid degradation indicated a reinforced transfer and utilization of E2. Cytochrome P450 monooxygenase (EstP1), 2-keto-4-pentenoate hydratase, pyruvate dehydrogenase, acetyl-CoA acetyltransferase, TonB-dependent receptor were involved in E2 catabolism. During downstream degradation, the metabolites with long-chain structure were decomposed adopting beta-oxidation pattern and ultimately entered the TCA cycle; 2 keto-4-pentenoic acid might be an emblematic product of such process. Furthermore, E2 converting to E1 was catalyzed by 17 beta-dehydrogenase probably encoded by IM701_16645 or IM701_16910; 4-OH-E1 meta-cleavage was catalyzed by a dioxygenase encoded by IM701_20340 or IM701_21000 or IM701_09625. Our study provided an in-depth insight into the adaptive responses and metabolic strategies of Novosphingobium to E2.