Kinetic process of the biosorption of Cu(II), Ni(II) and Cr(VI) by waste Pichia pastoris cells

ABSTRACT

Waste biomass of Pichia pastoris (P.pastoris) cells from the fermentation industry is an environmentally friendly biosorption material. The present study aimed to explore the biosorption behaviour of waste P.pastoris cells for Cu(II), Ni(II) and Cr(VI) in aqueous solution conditions. The results showed that the adsorption kinetics of three kinds of metals were well-fitted with lineared Elovich, pseudo-second-order kinetics models, non-linear kinetics and adsorption isotherms. The effective biosorption rates for Cu(II), Ni(II) and Cr(VI) removal were 71.3%, 59.7% and 16.25% respectively. The maximum Cu(II) adsorption capacity of waste P.pastoris was 40 mg/g at pH = 4 and 225 mg/L of solute concentration for 0.4 g biomass, better than that of the living yeasts. The pattern of Fourier transform infrared (FTIR) indicated that functional groups such as –NH, –OH, Si–O, P–O–C were involved in Cu(II) adsorption process. The analysis of SEM-EDS, XRD and TEM-EDS can be concluded that Cu(II) occupied Ca(II) binding sites by ion exchange mechanism to remove flocculation, and Cu(II) adsorbed onto the diatomite containing in the industrial waste P.pastoris. Thus the adsorption mechanism of the industrial waste P.pastoris was proposed taking Cu(II) as the example. And consecutive biosorption/desorption cycles were used for the evaluation of the regeneration efficiency, suggesting the good regeneration and reusability of waste P.pastoris.

GRAPHICAL ABSTRACT

KEYWORDS:

• Biosorption
• Pichia pastoris
• kinetics
• thermodynamics
• mechanism

Acknowledgments

We thank Flag Bio-Tech Co., Ltd. (in Changsha, China) for providing waste P.pastoris in this study, and thank LetPub (www.letpub.com) for its linguistic assistance and scientific consultation during the preparation of this manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article or its supplementary materials.

Additional information

Funding

This research was funded by Hunan Provincial Innovation Foundation For Postgraduate (grant number CX20190068), the Fundamental Research Funds for the Central Universities of Central South University (grant number 1053320184218), the National Natural Science Foundation of China (grant number 31870115) .