Project scope

Marine litter is a global problem. Fishery and aquaculture industries represent a major source of marine plastic litter. The traditional plastics used for fishery and aquaculture industries have a long lifespan in the marine industry and lead to plastic pollution and ghost fishing when they are lost in the sea. Recent research and industrial development have revealed the potential to develop biodegradable materials to replace the conventional plastics commonly used in the marine sector, especially those used in fishing and aquaculture industries.

Research partners: Arctic University of Norway, Norner Research AS, SINTEF Ocean, SINTEF Industry, Norsus, SALT Lofoten AS plus three international research partners.

Other partners: About 14 industrial partners from fisheries, aquaculture, and gear suppliers, as well as several public agencies and organizations from the fishery and aquaculture sector are also participating in the centre.

The solution

The goal of Dsolve is to replace traditional plastics with new biodegradable materials for fishery and aquaculture applications. The use of such materials would help to reduce the amount of marine plastic litter and its associated effects (macro-/microplastics and ghost fishing) in the marine environment. The new biodegradable materials will maintain the same properties as conventional plastics during their use but are completely degraded by the microorganisms when it is lost in the marine environment.

The biodegradation of plastic is a complex process that results in an extensive reworking of the carbon-containing compounds in the plastic by living organisms.

Biodegradation of plastics is the microbial conversion of all its organic constituents to carbon dioxide (CO2) (or carbon dioxide and methane in conditions where oxygen is not present), new microbial biomass and mineral salts within a timescale short enough not to lead to lasting harm or accumulation in the open environment. Carbon-carbon bonds cannot easily be broken, neither abiotically nor enzymatically. Therefore, polymers with only a carbon-carbon backbone will undergo the breakdown process extremely slowly in the open environment, thus hindering the conversion to CO2, CH4 and new microbial biomass. Polymers that contain heteroatoms like nitrogen, oxygen or phosphorus are often more readily broken down, e.g., by hydrolyzing enzymes. Further on, the biodegradation will depend on parameters such as crystallinity, surface-to-volume ratio and additives present in the polymer. With respect to the environment, the key parameters are temperature and the presence of microbial degraders, which catalyze the breakdown of plastics. All environmental factors that influence the activity of these microorganisms will therefore have an impact on the biodegradation process, e.g., temperature, moisture, availability of essential nutrients and electron acceptors, pH and salinity.

Confusion often exists among consumers between bio-based and biodegradable plastics and the polymers they are composed of, which are sometimes conflated under the term bioplastics. Bio-based polymers (or biopolymers) such as cellulose, starch, and lignin are composed of carbon derived from renewable biological sources such as plants, in contrast to fossil-based polymers. The fact that these plastics are bio-based, however, does not necessarily mean they are biodegradable, and both bio-based and fossil-based polymers can be either biodegradable or non-biodegradable. The origin and manufacturing process of biobased polymers have important environmental implications and should be considered for a full assessment of the overall environmental impact when alternative materials are considered to replace conventional plastics.

For plastic to biodegrade, it must undergo two key steps:

1 The polymer molecules (hydrocarbon chains) need to break down into smaller components of low molecular weight through enzymatic action. This first step depends to a large extent on the material properties of the plastics themselves and the environment in which they are located. In the open environment, this breakdown process typically needs weeks, months, or years to occur.

2 These smaller components must then be converted into CO2 (or CO2 and CH4 under anoxic conditions) and new microbial biomass, which is done by microorganisms. This second step is particularly dependent on the specific environmental conditions and, in the open environment, occurs typically within hours or weeks.

Norner is one of the work package leaders in the Dsolve project. The main objective of our work package is to develop a range of biodegradable plastic materials with controlled biodegradability and the properties needed for products used in fishing and aquaculture industries (e.g., twines and netting, ropes, gillnets, coatings, pots and traps, foils and boxes, pipes and connectors). The developed materials should meet a range of processing and performance requirements, including biodegradability.

Norner will develop new biodegradable plastic materials systematically. First, various material and product design options will be screened theoretically, and suitable ones will be selected for further development. The new material concepts developed in the Dsolve project will be evaluated for processability and performance, and further development requirements will be identified. The development process will be continued in an iterative manner until optimal materials are achieved.

The complexity of the challenge

Plastic can reach an open environment for a variety of reasons. For most plastic applications, the intended end-of-life scenario is disposal in a managed waste stream, where they can be recycled or composted, if applicable. However, plastics destined for managed waste systems at the end of their life can escape from such systems or reach the open environment as a result of improper disposal or littering.

Some plastic applications, on the other hand, are specifically intended to be used in the open environment. Loss may also be intrinsic to use, for example, dolly rope abrading to protect fishing gears. For applications such as fishing gear, a partial loss is considered unavoidable during normal use in the open environment. Although recovery from the environment for reuse or recycling would be preferable, for some of these applications, it is either impossible or disproportionally expensive. Biodegradable plastics have, in such cases, been proposed as part of a potential solution to plastic pollution. However, their environmental benefits over conventional plastics need to be carefully assessed.

In the context of a circular economy, it is of high importance that biodegradable plastics are not put forward as a solution to inappropriate waste management or littering. The use of biodegradable plastics should be limited to specific applications in the open environment for which reduction, reuse, and recycling are not feasible. Before the introduction of such degradable materials, it is of vital importance that biodegradation and environmental risk under the conditions of specific open environments are assessed. To avoid misuse and confusion, clear and accurate information will be required to address the current misconceptions and confusion related to bio-based, compostable and biodegradable plastics. Biodegradability of plastics should only be encouraged when it is beneficial to the environment and does not interfere with waste management systems, compromise food safety or represents a higher environmental footprint than the conventional plastics being used. The challenge addressed in Dsolve is significant. Currently, the materials fulfilling all the requirements we target do not exist. Through the systematic R&D approach we will explore if it is possible to enable biodegradable polymers to provide high performance when need it – and fast biodegradation when lost. We believe such significant challenges are solved together, and please contact dr. Chowreddy for if you are interested in joining forces.

The SFI-scheme is intended to promote innovation by supporting long-term industrially oriented research and forging close alliances between research-active enterprises and prominent research groups. The scheme is also expected to enhance technology transfer, internationalization and researcher training. The centres are co-financed by enterprises, host institutions and the Research Council of Norway. The enterprises participate actively in a centre’s governance, funding and research. The main criterion for selecting centres is their potential for innovation and value creation. The scientific quality of the research must be of a high international standard.

Photo by K. Cerbule