Dual-function strategy: simultaneous biopolymer production and lead biosorption by Bacillus paramycoides in single-batch fermentation process

TL;DR

A new method uses bacteria to both remove lead from water and produce a valuable biopolymer in a single process.

Contribution

This is the first report of integrating lead biosorption and PHA production in a single bacterial process.

Findings

Bacillus paramycoides achieved lead biosorption of 423 mg/g biomass in 72 hours.

Lead ions increased PHA production by up to 35.7% CDW by inducing oxidative stress.

PHA polymers helped protect bacterial cells from oxidative damage caused by lead.

Abstract

The conventional physicochemical processes of lead removal from contaminated wastewater are cost-intensive and generate toxic secondary wastes. Therefore, employing bacteria capable of lead biosorption will serve as a green, sustainable, safe and inexpensive process for lead removal, and its integration with polyhydroxyalkanoate (PHA) production will generate revenue. To integrate these two processes, Bacillus paramycoides isolated from the lake water were analyzed for lead biosorption and PHA production in mineral salt media containing lead nitrate at different incubation times. The bacterium showed a high lead biosorption of about 423 mg/g of biomass at 72 h of incubation, which was earlier not reported. Bacillus paramycoides produced polyhydroxybutyrate by utilizing sucrose in the media. The lead ions enhanced the PHA production up to 35.7% CDW in bacterial cells by inducing oxidative stress, and the ability of PHA polymer to adsorb lead ions prevented further oxidative damage to the cells. This study is the first report on using an integrated process approach for lead biosorption and PHA production in bacteria.

The online version contains supplementary material available at 10.1007/s10532-025-10160-2.

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