活動詳細資訊 Event Information
活動詳細資訊 Event Information
加入我的Google日曆

活動訊息最後更新時間 : 2017-09-01 14:35:34
開始日期 Starting Date:2017-09-15  10:30
結束日期 Ending Date:2017-09-15  11:30
會議狀態 State:確定 Definitive
主/協辦單位 Organizer:生物多樣性研究中心 Biodiversity Research Center
活動地點 Venue:跨領域科技研究大樓1 樓演講廳 Auditorium, 1st Floor, Interdisciplinary Research Building
活動備忘 Event Memo:

Abstract

        Steroids, comprising sterols, steroid hormones, and bile acids, are ubiquitous and abundant in nature. Steroids are largely produced by eukaryotes; however, their complete degradation is only accomplished by microorganisms. Steroids degradation is challenging because of their low aqueous solubility and complicated sterane structures. Aerobic steroids catabolism depends on molecular oxygen as a cosubstrate of oxygenases to activate and cleave the recalcitrant sterane. Consequently, steroids degradation in oxygen-limited environments (e.g., freshwater and marine sediments) is generally slow. Obviously, anaerobic biodegradation needs to substitute all oxygenase-mediated reactions by an oxygen-independent strategy to overcome the chemical recalcitrance of steroids. This article presents an overview of current knowledge on anaerobic steroids biodegradation. In the past two decades, several denitrifying proteobacteria capable of utilizing steroids as sole carbon and energy sources were described. The denitrifiers adopt a common metabolic pathway, the steroid 2,3-seco pathway, to degrade cholesterol and testosterone under anoxic conditions. The anaerobic steroid catabolic pathways include various unprecedented catabolic enzymes (e.g., the molybdoenzymes steroid C25 dehydrogenase and 1-testosterone hydratase/dehydrogenase), which introduce the hydroxyl groups in the aliphatic side-chain and sterane of steroid substrates, and the oxygen atoms originate from water. The corresponding genes were found in genomes of steroid-degrading, denitrifying bacteria. Multi-omics investigation of the environmental samples indicated the role of the established anaerobic steroid catabolic pathways in the natural and engineered ecosystems.
相關檔案 Related File