Modeling cometabolism of hexavalent chromium by iron reducing bacteria in tertiary substrate system

Shivangi Upadhyay,Alok Sinha

doi:10.1038/s41598-021-90137-2

Shivangi Upadhyay, Alok Sinha

Open Access

https://doi.org/10.1038/s41598-021-90137-2

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Abstract

In this study, a bacterial strain Serratia sp. was employed for the reduction of synthetically prepared different concentration of Cr(VI) solution (10, 25, 40, 50 and 100 mg/L). Cometabolism study have been carried out in the binary substrate system as well as in the tertiary substrate system. The results revealed that when glucose was added as a co-substrate, at low Cr(VI) concentration, complete reduction was achieved followed by increased biomass growth, but when Cr(VI) concentration was increased to 100 mg/L, the reduction decline to 93%. But in presence of high carbon iron filings (HCIF) as co-substrate even at higher Cr(VI) concentration i.e. 100 mg/L, 100% reduction was achieved and the cell growth continued till 124 h. The study was illustrated via Monod growth kinetic model for tertiary substrate system and the kinetic parameters revealed that the HCIF and glucose combination showed least inhibition to hexavalent chromium reduction by Serratia sp.

Highlights

In this study, a bacterial strain Serratia sp. was employed for the reduction of synthetically prepared different concentration of Cr(VI) solution (10, 25, 40, 50 and 100 mg/L)
Cometabolism study was conducted to evaluate the cometabolic activity of Serratia sp. in two different sets i.e. when glucose was added (1 g/250 mL) to batch reactors containing Cr(VI) and bacteria (Set 1) and when glucose was added to batch reactors containing Cr(VI), bacteria and high carbon iron filings (HCIF) (Set 2) for the reduction of hexavalent chromium by Serratia sp
The results from the study indicated that when only glucose acted as co-metabolic substrate, the biomass growth lasted till 60 h but when glucose was added to the HCIF and bacterial set, the bacterial growth continues till 120 h

Summary

Introduction

A bacterial strain Serratia sp. was employed for the reduction of synthetically prepared different concentration of Cr(VI) solution (10, 25, 40, 50 and 100 mg/L). To reduce the inhibitory effect of Cr(VI) on the bacteria, this study demonstrates the use of glucose and high carbon iron filings (HCIF) as cometabolic substrates for microbial reduction of Cr(VI). Results and discussion Reduction of Cr(VI) in batch reactors in the presence of cometabolic substrate (HCIF and glucose).

Results

Conclusion