Bioconversion of plastic waste into microbial polyhydroxyalkanoates

Title : Bioconversion of plastic waste into microbial polyhydroxyalkanoates

Abstract:

Fossil fuel-based plastics play a crucial role in modern society, with global production reaching approximately 400 million tonnes annually. However, their widespread use and persistence in the environment have raised major concerns regarding their impacts on ecosystems, biodiversity, human health and the economy. Despite ongoing efforts to promote plastic recycling and reuse, complementary strategies are needed to improve plastic waste management and support the transition toward a circular economy. In this context, the biological upcycling of plastic waste into value-added products has emerged as a promising approach. Polyhydroxyalkanoates (PHA) are biodegradable and biocompatible polyesters naturally accumulated by various bacteria as carbon and energy storage compounds. Owing to their versatile material properties and potential to replace conventional petroleum-based plastics, PHA have attracted increasing interest as sustainable bioplastics. Their microbial production from waste-derived carbon sources offers an opportunity to couple plastic waste valorization with bioplastic synthesis. In particular, the conversion of polyethylene terephthalate (PET)-derived compounds, such as terephthalic acid (TA), into valuable bioproducts represents a promising strategy for advancing sustainable plastic waste management. Thus, this study evaluated the ability of several bacterial strains to bioconvert TA derived from reactive extrusion (REX)-treated PET waste, supplied as the sole carbon source, into PHA. PHA production and polymer composition were determined by gas chromatography (GC), while TA consumption was monitored by quantifying residual TA in the culture medium using high-performance liquid chromatography (HPLC). These results demonstrate the feasibility of converting PET-derived TA into PHA through microbial bioconversion, offering a sustainable biotechnological route for PET waste upcycling. This approach thus contributes to the development of circular strategies that couple plastic 

Keywords:  polyhydroxyalkanoates; polyethylene terephthalate; bioconversion; plastic wastes

Biography:

Dr Khouloud Hammami, she hold a PhD in Biotechnology, Health and Environment from the Higher Institute for Biotechnology of Sidi Thabet (ISBST), University of Manouba, Tunisia, where she am currently a postdoctoral researcher at the Laboratory of Biotechnology and Bio-Geo Resources Valorization. My PhD research focuses on the bioconversion of organic and plastic wastes into polyhydroxyalkanoate (PHA) bioplastics using extremophilic bacteria. she have published five first-author articles, including work on Halomonas desertis G11, and completed a research stay at NOVA School of Science and Technology (Lisbon), where she trained in biopolymer characterization and bioreactor production.  Khouloud Hammami, she hold a PhD in Biotechnology, Health and Environment from the Higher Institute for Biotechnology of Sidi Thabet (ISBST), University of Manouba, Tunisia, where she am currently a postdoctoral researcher at the Laboratory of Biotechnology and Bio-Geo Resources Valorization. My PhD research focuses on the bioconversion of organic and plastic wastes into polyhydroxyalkanoate (PHA) bioplastics using extremophilic bacteria. she have published five first-author articles, including work on Halomonas desertis G11, and completed a research stay at NOVA School of Science and Technology (Lisbon), where she trained in biopolymer characterization and bioreactor production.