Related Experiment Video
Updated: May 16, 2026
08:14
Scalable Step-by-Step Approach of Sustainable Bioplastic Production from Food Waste
Published on: July 18, 2025
Process optimisation for polyhydroxyalkanoates production with tailored hydroxyvalerate content from agri-food
Giovanna Pesante1, Claudia Magonara2, Alessia Zucca2
1Department of Biotechnology, University of Verona, 37134, Verona, Italy. giovanna.pesante@univr.it.
Biotechnology for Biofuels and Bioproducts
|May 15, 2026
Summary
Producing poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) from agri-food waste using mixed microbial cultures (MMC) is feasible. Pretreatment, specifically filtration, significantly enhances PHBV yield and microbial selection for efficient biopolymer production.
Area of Science:
- Biotechnology
- Polymer Science
- Circular Economy
Background:
- Polyhydroxyalkanoates (PHAs) are biodegradable polymers crucial for a circular bioeconomy.
- Utilizing mixed microbial cultures (MMC) and agri-food residues for PHA production presents challenges in substrate variability and process control.
- A three-stage process was developed to produce poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) from cattle slurry and corn residues.
Purpose of the Study:
- To investigate a three-stage process for PHBV production from agri-food residues using MMC.
- To compare two setups differing in feedstock pretreatment (centrifugation vs. filtration) for PHA production efficiency.
- To evaluate the impact of pretreatment on PHA yield, titre, composition, and microbial community structure.
Main Methods:
- Acidogenic fermentation of cattle slurry and corn residues to produce a carboxylic acid (CA)-rich stream.
- Microbial selection using feast-famine conditions to enrich PHA-accumulating microorganisms.
- PHA accumulation in fed-batch reactors with comparison between centrifuged and filtered fermentate.
- Microbial community analysis to assess the impact of filtration on microbial populations.
Main Results:
- Acidogenic fermentation yielded up to 18.6 gCOD/L of CAs. Filtration (setup 2) significantly improved PHA production compared to centrifugation (setup 1).
- Setup 2 achieved higher mean storage yields (0.78 gCODPHA/gCODCA) and PHA titres (1.70 g/L) with intracellular PHA content up to 57.0% w/w.
- Filtration led to a more stable PHBV composition and a microbial community dominated by specialized PHA-storing genera, indicating effective selection.
Conclusions:
- MMC-based PHBV production from agri-food residues is viable and can achieve competitive polymer content.
- Feedstock pretreatment, particularly filtration, is critical for enhancing PHA production efficiency and stability.
- Further optimization of operational aspects is needed to improve process robustness and product consistency for industrial application.
Related Concept Videos
01:25Production of Organic Acids
Lactic acid, an important organic acid extensively applied in food, pharmaceutical, and biodegradable polymer industries, is primarily produced via microbial fermentation. This method is favored over chemical synthesis due to its environmental sustainability and capacity for enantiomerically pure product formation. Among various microbial processes, the fermentation of starch-based substrates stands out due to the abundance and renewability of raw materials like corn and potatoes.Hydrolysis of...
01:27Bioplastics
Bioplastics derived from microbial processes present a sustainable alternative to conventional petroleum-based plastics. Among these, polyhydroxyalkanoates (PHAs), particularly polyhydroxybutyrates (PHBs), have emerged as prominent candidates due to their biodegradability and biocompatibility. These polymers are synthesized by a variety of bacteria, such as Cupriavidus necator and Pseudomonas putida, which naturally accumulate PHAs as intracellular carbon and energy reserves, especially under...
01:22Bioreactor Controls-III
Strain improvement is a foundational strategy in industrial microbiology aimed at maximizing microbial productivity, particularly because natural isolates typically yield commercially valuable products in very low concentrations. Although optimizing the culture medium and environmental conditions can improve yields, these adjustments are inherently limited by the organism’s genetic potential. As a result, the focus shifts toward genetic modifications to enhance biosynthetic capacity. The...
01:29Microbes in Food Production
Microbial fermentation is central to food biotechnology, enhancing flavor, texture, preservation, and stability. Fermentative microorganisms metabolize carbohydrates into organic acids, alcohols, and other metabolites that inhibit spoilage organisms and improve digestibility while contributing distinctive sensory qualities.In baking, amylases naturally present in flour hydrolyze starch into monosaccharides such as glucose, which Saccharomyces cerevisiae ferments anaerobically. Through...
01:27Upstream Processing
Upstream processing represents a critical phase in biomanufacturing, wherein biological systems such as microorganisms, mammalian cells, or insect cells are cultivated to produce therapeutic proteins, vaccines, enzymes, or other biologically derived products. This phase encompasses all steps from the selection and genetic manipulation of the production organism to the cultivation of cells in bioreactors under tightly controlled environmental conditions.Host Selection and Genetic OptimizationThe...
01:28Microbial Bioremediation of Plastics
Polyethylene terephthalate (PET) is a synthetic polymer widely utilized in the packaging industry, particularly for bottles and containers. Due to its chemical stability and durability, PET accumulates in the environment, contributing significantly to plastic pollution. It comprises repeating units of terephthalic acid and ethylene glycol, resulting in a semi-crystalline structure that is resistant to natural degradation processes.A notable breakthrough in plastic biodegradation came with the...