scalable-step-step-approach-sustainable-bioplastic-production-from

Scalable Step-by-Step Approach of Sustainable Bioplastic Production from Food Waste

The global microplastic crisis, coupled with the growing challenges of food waste disposal, necessitates innovative solutions to address these ...

Virginia Polytechnic Institute and State University

Volatile fatty acids (VFAs) derived from arrested anaerobic digestion (AD) can be recovered as a valuable commodity for value-added synthesis. However, separating VFAs from digestate with complex constituents and a high-water content is an energy-prohibitive process. This study developed an innovative technology to overcome this barrier by integrating deep eutectic solvents (DESs) with an omniphobic membrane into a membrane contactor for efficient extraction of anhydrous VFAs with low energy consumption. A kinetic model was developed to elucidate the mechanistic differences between this novel omniphobic membrane-enabled DES extraction and the previous hydrophobic membrane-enabled NaOH extraction. Experimental results and mechanistic modeling suggested that VFA extraction by the DES is a reversible adsorption process facilitating subsequent VFA separation via anhydrous distillation. High vapor pressure of shorter-chain VFAs and low Nernst distribution coefficients of longer-chain VFAs contributed to DES-driven extraction, which could enable continuous and in-situ recovery and conversion of VFAs from AD streams.

Anhydrous volatile fatty acid extraction through omniphobic membranes by hydrophobic deep eutectic solvents: Mechanistic understanding and future perspective.

Bioplastics made of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with a 20 mol% HV fraction are highly desirable in the market for 3-Hydroxyvalerate (HV)-conferred superior thermal, biological, and mechanical properties. Although Haloferax mediterranei (HM) is capable of producing PHBV from food waste, its HV fraction is generally lower than 10 mol%. This study for the first time investigated the engineering approach to increasing HV fraction through elevating the propionic and valeric acid fractions in volatile fatty acids (VFAs) produced from food waste via arrested anaerobic digestion with and without microbial electrolysis cells (MECs) incorporation. Results showed that HV fraction in PHBV produced by HM is proportional to the fractions of propionic and valeric acids in VFAs. A 20 mol% HV fraction can be achieved by MECs incorporation, which might be attributable to pH regulation by the MECs. These findings lay a foundation for developing waste-processing technologies that enable the production of high-value, microbially-derived materials.

Enhancement of 3-hydroxyvalerate fraction in poly(3-hydroxybutyrate-co-3-hydroxyvalerate) produced by Haloferax mediterranei fed with food waste pretreated via arrested anaerobic digestion integrated with microbial electrolysis cells.

This study investigated the role of maintenance energy expenditure in driving polyhydroxyalkanoate (PHA) production from food waste digestate using Haloferax mediterranei. A theoretical model was developed to describe the inhibitory effects on cellular PHA content based on substrate allocation on maintenance energy. This model offered a generalized understanding of the positive correlations between inhibitory effects and corresponding PHA production. For the first time, a method was proposed and experimentally validated to quantify the extent of inhibition, providing an approach to assessing these inhibitory effects. Furthermore, the minimum inhibitory conditions necessary for H. mediterranei to achieve maximum PHA production without excessively compromising cell biomass growth were identified. These findings not only elucidate the intrinsic relationship between maintenance energy expenditure and PHA production but also establish a novel framework for leveraging inhibitory effects, such as those from food waste digestate, to promote sustainable and cost-effective bioplastic production, thereby contributing to circular economy.

Article	Year
Anhydrous volatile fatty acid extraction through omniphobic membranes by hydrophobic deep eutectic solvents: Mechanistic understanding and future perspective. Water research\| PubMed ID: 38701552	2024
Enhancement of 3-hydroxyvalerate fraction in poly(3-hydroxybutyrate-co-3-hydroxyvalerate) produced by Haloferax mediterranei fed with food waste pretreated via arrested anaerobic digestion i... Bioresource technology\| PubMed ID: 40228720	2025
Maintenance energy-driven polyhydroxyalkanoates production from food waste digestate by Haloferax mediterranei. Bioresource technology\| PubMed ID: 40645381	2025

Xueyao Zhang

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