Abstract: Dissimilatory Fe(Ⅲ)-reducing bacteria are spread throughout the domain of bacteria and archaea. They are phylogenetically diverse and have been isolated under various environment conditions. Unlike other electron acceptors, Fe(Ⅲ) has a very low solubility and exists primarily as insoluble Fe oxide under neutral pH. At present, the mechanisms of gathering and reducing Fe(Ⅲ) are still poorly understood. Taking Shewanella and Geobacter as examples, this paper reviewed three kinds of possible mechanisms of microbial enzyme-catalyzed dissimilatory Fe(Ⅲ) reduction and its molecular regulation, i.e., direct contact between microbial cell and Fe(Ⅲ) oxides, siderrophores, and electron shuttling compounds. Many membrane-bound cytochrome proteins are involved in the dissimilatory Fe(Ⅲ) reduction, forming a complicated regulation network. This paper also proposed future research directions on the mechanisms of enzyme-catalyzed dissimilatory Fe(Ⅲ) reduction so as to better understand this important biochemical process.

Key words: Eisenia fetida, Bt toxin Cry1Ac, Protein content, CAT, AchE, Cellulase, GST