A novel approach of utilization of the fungal conidia biomass to remove heavy metals from the aqueous solution through immobilization.

Chun-Xiang Cai,Xue-Wei Dong,Yu Liang,Jian Xu,Xian-Wei Fan,You-Zhi Li,Hao Tang,Nian-Fang Deng

doi:10.1038/srep36546

Chun-Xiang Cai, Xue-Wei Dong + Show 6 more

Open Access

https://doi.org/10.1038/srep36546

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Abstract

The biomass of filamentous fungi is an important cost-effective biomass for heavy metal biosorption. However, use of free fungal cells can cause difficulties in the separation of biomass from the effluent. In this study, we immobilized the living conidia of the heavy metal-resistant Penicillium janthinillum strain GXCR by polyvinyl alcohol (PVA)-sodium alginate (SA) beads to remove heavy metals from an aqueous solution containing a low concentration (70 mg/L) of Cu, Pb, and Cd. The PVA-SA-conidia beads showed perfect characters of appropriate mechanical strength suitable for metal removal from the dynamic wastewater environment, an ideal settleability, easy separation from the solution, and a high metal biosorption and removal rate even after four cycles of successive sorption-desorption of the beads, overcoming disadvantages when fungal biomasses alone are used for heavy metal removal from wastewater. We also discuss the major biosorption-affecting factors, biosorption models, and biosorption mechanisms.

Highlights

Use of free fungal cells can cause difficulties in the separation of biomass from the effluent
We investigate heavy metal removal by using GXCR conidia immobilized in polyvinyl alcohol (PVA) and sodium alginate (SA) to develop a new technology to remove the heavy metals from wastewater, while characterizing the mechanisms associated with heavy metal removal
To remove the heavy metals from aqueous solutions, most of the previous studies employed filamentous forms of the fungal biomass immobilized in forms of beads[26,27,28,29,30], pieces[31], columns[26,32], discs[33], or reticulated polyester foam biological support particles[32], and these studies focused on equilibrium and kinetic studies

Summary

Introduction

Use of free fungal cells can cause difficulties in the separation of biomass from the effluent. Metal biosorption by dead microbial biomass is only surface-area limited passive adsorption[19], whereas the application of living cells is obviously advantageous via diverse internal metabolism-dependent metal-resistance mechanisms such as metal detoxification and bioaccumulation[13,20] with sustained cell growth the costs associated with maintaining living cells reduce cost-effectiveness[4]. These biologically-mediated processes are often termed ‘biosorption’ rather than bio-adsorption or bio-uptake[21]. In this case, growing metal-resistant cells would be preferable in metal

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