Enhanced Biosorption of Nickel Ions on Immobilized Surface-Engineered Yeast Using Nickel-Binding Peptides.

Hua Li,Wei Dong,Gang Wang,Haiyan Zhang,Yong Liu

doi:10.3389/fmicb.2019.01254

Abstract

Three nickel-binding peptides were screened from a phage peptide library and displayed separately or in combination with surface-engineered Saccharomyces cerevisiae EBY100. The sorption of nickel ions on the surface of yeast cells increased with the increasing number of nickel Ni(II)-binding peptides displayed. The combined expression of the three peptides by EBY100/pYD1-N123 demonstrated the highest sorption of Ni(II) (2.603 ± 0.004 g g−1, dry weight) and an enhanced sorption capacity of 60.15%, compared to S. cerevisiae EBY100. An orthogonal test for yeast immobilization was designed. A maximum sorption capability of 68.62% was observed for a treatment at 25°C with 2.0% calcium chloride and 3.0% sodium alginate.

Highlights

Diverse adverse results of heavy metal including Ni exposure have been reported in humans and animals (Zhang et al, 2014; Guo et al, 2015; Biscéré et al, 2017)
The aim of this study is to demonstrate whether the recombinant S. cerevisiae cells with three Ni-binding peptides transformed onto the surface which were immobilized in the alginate gel can perform as a high-capacity bioadsorbents for nickel adsorption from wastewater
Phage display is a versatile technology for the discovery of peptides which bind to any desired target (Cindy et al, 2008; Bratkovic, 2010)

Summary

Introduction

Diverse adverse results of heavy metal including Ni exposure have been reported in humans and animals (Zhang et al, 2014; Guo et al, 2015; Biscéré et al, 2017). The expression of heterologous metal-binding proteins or peptides on the cell surface through microbial cell-surface display systems enables specific binding of heavy metals and improves the resistance of microorganisms to metal and sorption of cells. The combination of microbial metal-binding protein with surface-expressed system has been utilized to treat heavy metal wastewater. A Hg2+-binding protein that was surface-expressed on the ice-nucleation protein of Escherichia coli binds six-fold more than the wild-type strain (Bae et al, 2003). Yeast display system has the merit of the protein modification and processing in yeast occurs after translation, and the heterologously expressed protein cannot be degraded by proteases (Kuroda and Ueda, 2013; Li et al, 2017)

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