PHA PILOT PLANT

Innoven srl, thanks to the participation to European Union and Veneto Region financed projects, is proud to own a pilot plant (located at Isola Della Scala, Verona, Italy) for producing polyhydroxyalkanoates (PHA) enriched biomass, which represent the base to produce for producing bioplastics from agro-industrial wastes.

WHAT ARE POLYHYDROXYALKANOATES?

Polyhydroxyalkanoates (PHAs) are aliphatic polyesters well known for their biodegradable properties and their bacteria-based production methods. Based on the potential combination of monomer units, a huge number of PHA copolymers can be formed. PHAs, which are biodegradable in various environments, represent an attractive option to replace current single-use plastics or plastics that are unsuitable for  recycling because of their inferior quality. Due to biodegradable properties, PHAs form a closed loop that minimises the impact on the environment. However, functionality and production methods depend on the type of PHA.

The short- and medium-chain length PHAs are the only ones with double bonds. The best-known polyhydroxyalkanoates are poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), both of which are short-chain PHAs and represent the most basic forms commercially available.

PHAs for commercial use are generally produced by recombinant Escherichia coli but can be produced by a number of other microorganisms belonging to different genera, among them (e.g. Aeromonas, Azotobacter, Cupriavidus, Clostridium, Methylobacterium, Ralstonia, Pseudomonas, Syntrophomonas etc.).

THE PILOT PLANT AT ISOLA DELLA SCALA

This is the beating heart of Innoven’s research and development. It was built with European funds with the aim of being used within projects in which the company has always played a crucial role by supplying the biomass rich in polyhydroxyalkanoates (PHA).

The plant is composed of several units to ensure a continuous and synchronous process between the different sections:

– SUBSTRATE PRE-TANK: used as mixing point of the substrates (agricultural digestate as an inoculum and a carbonaceous source that will be the source of energy and metabolism for the microorganisms);

– FERMENTER: Where anaerobic process of transforming the substrate into simpler carbonaceous forms takes place. This gives origin to volatile fatty acids (VFA) such as acetic acid, propionic acid, etc. They are different in the number of carbons in the molecule.

– FILTRATION: the fermented product is clarified through special filters to remove all suspended solids  in order to obtain a permeate rich in VFA.

– SEQUENCING BATCH REACTORS: these are two reactors in which the actual PHA ‘enrichment’ of the bacterial cells takes place. Through a process called ‘feast and famine’, the bacterial cells are forced to accumulate as much as possible of the polymer inside them as possible.

– BIOMASS THICKENING: the bacterial activity is blocked by ‘quenching’ and the collection of the thickened biomass, and its subsequent freezing takes place.

The process is completed with the extraction of the polymer from the cells, which can be done with chemical reagents or organic solvents.