LOOP4PACK, an integrated approach from PHAs biosynthesis to their formulation & shaping. The project is organized into four scientific tasks (T1 to T4) and one project management and dissemination task (T0)

Legend (T=Tasks)

T1: PHAs Biosynthesis

T2: PHAs recovery

T3: PHAs charac. & formulation

T4: Cost and Environnemental Impact Assessment

LOOP4PACK aims at extending and controlling PHAs functionalities. Targeted performances will be achieved by combining two strategies:

  1. at the biosynthesis level (Task 1 (T1)), polymers of higher chain length such as (P(3HB-co-3HV) with high 3HV content and mcl-PHAs will be produced. These polymers are excellent candidates for packaging due to their thermoplastic properties 10 ;
  2. at the formulation level (T3), PHAs will be mixed with fully biodegradable and biobased nucleating agents and/or fillers to take benefit of composite structures 18,19.

In addition, the impact of PHA recovery methods (T2) on their molecular weight and thermo-mechanical properties will be assessed.

The achievement of this objective will be guided by a product/market study (Q4) in order to better target the needs of manufacturers and the characteristics of the packaging to be substituted, as well as the markets.

LOOP4PACK aims at reducing PHAs-based material cost and environmental impacts at each step of the process:

    1. at the biosynthesis level (T1), low-cost feedstocks will be used (agro-food by-products) in closed loop;
    2. at the recovery level (T2), the alkali treatment will serve as a basis because it appeared as one of the most favorable chain with production costs of 1.40 €/kg PHB, global warming potential of 2.4 kg CO2-eq/kg PHB and non-renewable energy use of 106 MJ/kg PHB17 ;
    3. at the formulation level (T3), PHAs will be blend with low cost biobased and biodegradable fillers decreasing the overall cost of the PHAs-based material;

Finally, the achievement of adapted properties for packaging applications will allow bringing higher added-value to the materials (T1-3) and a cost assessment will be performed (T4).

illustrations of project organization and tasks

The objective of task 1 is to study the microbial production of PHAs of different grades to be characterized and processed for making materials such as packaging. This task is carried out by the Symbiose team of TBI (Partner INSA Toulouse) and by the IRB team of IATE (Partner UM).

The originality of this work will be:

  • to compare the production potentialities of both pure culture and open mixed microbial cultures (MMC)
  • to get co-polymers of hydroxyvalerate (HV) and hydroxybutyrate (HB) with HV content of 10 to 50 %;
  • to produce mcl-PHA both using both pure cultures and open MMC
  • to compare PHAs production both on simple substrates (volatile fatty acids or glucose) or on complex feedstocks

The scientific approaches developed are based on understanding, quantifying and modeling the microbial transformations within industrial constraints.

Tailored PHAs will be provided to Task 2 and 3 for recovery, characterization and processing of PHAs. Material and energy fluxes will be provided to task 4 for economic and Life Cycle Assessment (LCA).

The task 1 is divided into 3 subtasks:

  • Task 1.1. Pretreatment of McCain residues to produce substrates for PHAs biosynthesis
  • Task 1.2. P(3HB-co-3HV) biosynthesis with high HV content
  • Task 1.3. mcl PHAs biosynthesis
Leader: Etienne Paul
The objective of task 2 is to develop and improve a method for the extraction-purification of microbially produced PHAs and to scale-up this method. This task is carried out by CRITT-Bio (Partner INSA Toulouse). The specifications for obtaining a method that respects the environment and minimizes production costs while ensuring the production of high quality PHAs are as follows:

  • No use of organic solvent: a mechanical cell disruption method will be explored.
  • A minimum PHA recovery rate of 80%.
  • A minimum required purity of 90%.
  • A limited impact of the method on the molecular weight of the extracted PHAs

The method will be developed both with batches of biomass from mixed and pure cultures, ensuring a robust and broad spectrum method.

The scale-up of the developed method will be carried out in order to extract significant quantities of PHAs (up to 1 kg) from batches of biomass provided by Task 1, for the achievement of the characterization and formulation of PHAs (T3).

Task 2 is thus divided into 2 subtasks:

  • Task 2.1. Recovery method implementation
  • Task 2.2. Recovery method scale up & recovery of PHA batches up to 1 kg
Leader: Elise Blanchet

The objective of Task 3 is the development of new food packaging materials from the PHAs produced in Task 1 and extracted in Task 2, in relation to the needs of the McCain company which serves as a case study. To this end, Task 3 aims to deepen the understanding of the relationships between the structure of PHAs (composition, molecular weight, sequential distribution of monomer units, crystallinity), their processability and the final properties of the materials (thermal properties, mechanical properties, gas and water barrier properties). This issue has already been widely addressed for P(3HB) and P(3HB-co-3HV) with low 3HV content. However, the impact of the composition, sequential distribution of monomer units and molecular weight of polymers with high 3HV content and mcl-PHAs on the final properties of the materials remains poorly known. Task 3 of the LOOP4PACK project thus aims to study the influence of these structural parameters on the thermomechanical properties of PHAs, via the supply of samples of controlled and contrasted molecular mass (production in task 1 of PHAs from different strains and consortia and under different conditions, and use in task 2 of different extraction methods).

Finally, since PHAs are recovered in the form of fine powders, a pre-mixing step (i.e. compounding by melt extrusion) is necessary to allow the shaping of the packaging materials using conventional plastics processing equipment. The addition of nucleating agents is notably required to increase the crystallization kinetics of PHAs, which are naturally very slow. Furthermore, due to the thermal sensitivity of PHAs, it has already been shown for P(3HB) and P(3HB-co-3HV) with low 3HV content, that optimization of processing conditions is particularly important to control the final properties of the materials. Finally, in view of food packaging applications, a high degree of purity is considered necessary. However, the crystallization phenomena and the thermomechanical behavior of polymers with a high 3HV content and mcl-PHAs deserve further investigation. Task 3 of the LOOP4PACK project thus aims to provide new knowledge on the crystallization mechanisms of high 3-HV PHBVs and mcl-PHAs, with a focus on the impact of PHA purity.

Task 3 is thus divided into 3 subtasks:

  • Task 3.1 – Characterization of PHA powders produced in task 1 and extracted in task 2 (molecular weight, thermal properties, crystallinity, thermal stability).
  • Task 3.2 – Compounding of PHAs produced in task 1 and extracted in task 2 (formulation using conventional nucleating agents).
  • Task 3.3 – Shaping and Study of Structure/Properties Relationships in PHA-based Materials
Leader: Hélène Angellier-Coussy

The main objective of Task 4, coordinated by McCain with the support of the EuraMaterials cluster and the collaboration of the INSA and UM IATE laboratories, is to evaluate the economic and industrial impacts of the project by collecting and analyzing information:

  • on the raw materials available in the regions (Hauts de France, New Aquitaine and Occitania) through the typologies and volumes of co-products generated by the agri-food industries. This study will be refined according to the project data (from T1) in order to target the most relevant raw materials in relation to the project’s needs.
  • on the needs of the companies and the characteristics of the packaging to be substituted; market of flexible films and food trays awaiting substitution products with end-of-life characteristics related to biodegradability and/or compostability. On the review of biobased products already on the market and the improvements to be made.
  • on initially targeted markets or specific application markets linked to the properties of the materials developed within the project
  • on the processes to be implemented throughout the packaging production value chain and their environmental impact via a comparative LCA (vs. oil-sourced products). LCA that will make it possible to consider and arbitrate among the different recovery methods to be followed.

Task 4 is thus divided into 3 subtasks:

  • Task 4.1. Feedstock resource assessment
  • Task 4.2. Product/market assessment
  • Task 4.3. Life Cycle Assessment
Leader: Pierre Gondé