Localization effect on the metal biosorption capability of recombinant mammalian and fish metallothioneins in Escherichia coli

Wei Chen Kao, Yao Pang Chiu, Chia Che Chang, Jo Shu Chang

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

In this study, we examined the expression of mammalian and fish metallothioneins (MTs) in Escherichia coli as a strategy to enhance metal biosorption efficiency of bacterial biosorbents for lead (Pb), copper (Cu), cadmium (Cd), and zinc (Zn). In addition, MT proteins were expressed in either the cytoplasmic or periplasmic compartment of host cells to explore the localization effect on metal biosorption. The results showed that MT expression led to a significant increase (5-210%) in overall biosorption efficiency (ηads), especially for biosorption of Cd. The MT-driven improvement in metal biosorption relied more on the increase in the biosorption rates (r2, a kinetic property) than on the equilibrium biosorption capacities (qmax, a thermodynamic property), despite a 10-45% and 30-80% increase in qmax of Cd and Zn, respectively. Periplasmic expression of MTs appeared to be more effective in facilitating the metal-binding ability than the cytoplasmlic MT expression. Notably, disparity of the impacts on biosorption ability was observed for the origin of MT proteins, as human MT (MT1A) was the most effective biosorption stimulator compared to MTs originating from mouse (MT1) and fish (OmMT). Moreover, the overall biosorption efficiency (ηads) of the MT-expressing recombinant biosorbents was found to be adsorbate-dependent: the ηads values decreased in the order of Cd > Cu > Zn > Pb.

Original languageEnglish
Pages (from-to)1256-1264
Number of pages9
JournalBiotechnology Progress
Volume22
Issue number5
DOIs
Publication statusPublished - 2006 Sep 1

All Science Journal Classification (ASJC) codes

  • Biotechnology

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