ERA-NET: Wood and derivatives protection by novel bio-coating solutions

Wood decay is caused by microorganisms, especially fungi, and by insects, and often a combination of the two. The preservation of wood is an old and continuous challenge. Traditionally, very toxic, broad-spectrum biocides were used for wood preservation, but new environmental regulations have forced a change to more specific and less toxic biocides. However, the new agents are in general more expensive and less effective. The main goal of the ProWood project has been to develop economic and ecologically friendly wood protection agents based on microorganisms, biological compounds, and natural biomass-derived fillers to be incorporated into bio-coatings based on vegetable oils, non-petroleum-based polymers, and gels. ProWood has partners in Spain, Germany, Romania, and Turkey in addition to SINTEF in Norway. The Spanish partner isolated and characterized cultivable microorganisms to identify microorganisms with anti-decay properties. Other partners developed polymer matrices ("paints") for incorporation of decay preventing agents and testing the properties of the different combinations in laboratory scale. SINTEF's contribution has been to provide the project with wood at different stages of rotting, identifying microorganisms and microbial metabolic processes that occurs during wood rotting, identifying microorganisms and compounds with anti-decay properties and the production of bio-based anti-decay compounds. To study the initial phase of the wood decay process in different climates, standardized wood bricks with and without treatment with commercial Cu-based preservatives, and bricks with bio-based coatings, have been distributed to the partners and used in exposure experiments. In Trondheim, 18 different types of bricks (in total 270 bricks) have been mounted on rigs in 3 different positions at a test area that also has a weather station administrated by the Norwegian meteorological institute. Samples of the bricks were collected twice a year during a 2 year period, i.e. 16.10.2018, 24.04.2019, 22.10.2019, and 15.04.2020. To identify and isolate a broad spectrum of decay-related microbial communities, 64 samples from different species of trees, locations, and seasons in forests in Norway and Spain were also collected. SINTEF has established procedures for and analysed a selection of forest wood samples with three methods to evaluate the rotting process: Traditional methods, metagenomics, and metatranscriptomics. The traditional methods measure how solid the wood sample is, its pH and density. By extracting and sequencing total DNA in the sample (metagenomics), the type and abundance of bacterial and fungal taxa in wood samples from different locations and in different stages of decay can be determined. Our hypothesis is that the complex microbial flora in decaying wood also contain microorganisms that through their metabolic processes or products inhibit or slow down the wood decay process. By comparing the metagenome results with the characteristics of strains isolated from the same samples by our partners, we are able to identify the isolates that represent a significant fraction of the community in the decaying wood sample, and not only are species that are easy to isolate in the laboratory, but constitute an insignificant fraction of the flora in the decaying wood sample. The third level of characterization is the study of the expressed genes in the decaying wood sample (metatranscriptomics). This gives information about the metabolic processes in the microorganisms living in decaying wood and may be used to identify possible targets for anti-decay products. Minimum Inhibitory Concentration assays for 5 reporter fungi, used by partners in competitive bioassays, was established at SINTEF and used to evaluate the inhibitory effect of biological filler candidates. Together with the Spanish partner we have genome sequenced three Bacillus strains isolated from Norwegian and Spanish forests that can inhibit the growth of several rot causing fungi. Cell extracts from these strains as well as extract from eucalyptus wood were further characterized for antifungal activity employing our high throughput screening laboratory at SINTEF. Due to the covid-19 outbreak there has been no physical meetings in 2020. A final telecon with all the partners is planned.

ProWood har bidratt til det pågående grønne skiftet som pågår i verden ved å utvikle nye biobaserte tokomponent-malinger for beskyttelse av trevirke. Disse slipper ut færre giftige biprodukter enn petrokjemiske alternativer og tar utgangspunkt i fornybare ressurser. Tilsats av biologiske fyllmaterialer har dessuten vist forbedret beskyttelse mot testede mugg- og råtesopper. SINTEF har etablert bioassay mot relevante mugg- og råtesopper som kan brukes også i videre prosjekter bl.a. i studier av biologisk hemming av disse soppene. Vi har også genomsekvensert 3 bakterier og kartlagt mikrofloraen som er involvert i forråtnelse av trær i skogsterreng. Gjennom et kontrollert, toårig feltstudium i en urban setting har vi dessuten studert endring i mikrofloraen som koloniserer og bidrar til nedbrytning av ubehandlet og behandlet trevirke og bidratt til økt forståelse for hva som skjer i de tidlige stadiene av nedbrytning av tre.

The European Union (EU27) woodworking industry consists today of more than 380,000 companies and employs more than 2.1 million workers. The European industrial interest on wood decay processes is both to accelerate (biorefinery) and to prevent wood degradation (decay). While, the hydrolytic degradation processes are extensively studied and improved for biofuels production, the prevention of wood degradation has received less attention, even though, the preservation of wood structures against decomposition is an old challenge. The effect on wood of environmental factors (sun, water, chemicals or fire) and, due to its natural origin, low resistance against biotic agents (moulds, bacteria and insects) cause a progressive diminution of its mechanical properties and biodeterioration. Although, there are products for wood protection available on the market they do not meet the expectations in terms of efficiency, price and long term activity, whereas some of them release toxic substances. The project ProWood (Protection of Wood) is an interdisciplinary 6-members Consortium of molecular biologists, (bio)chemical engineers and industrial partners selected for their know-how in biotechnology, bio-coating development, wood handling and validation processes. ProWood aims the development of novel solution(s) for wood decay protection under the light of the previous and successful developments and knowledge of the Partners. Thus, the combination of bio-based coating solutions with biological decay antagonists guarantees an industrial-relevant solution. The workplan of ProWood consists of four Research and Analysis workpackages (WP) and one of Management and Dissemination. These WPs cover the process from the initial definition of coating precursors (chemistry) and the biological antagonists (biotechnology) to the combined coating demonstration and validation (industry) and the industrial use (market). Thus, ProWood walks along the entire value chain of wood protection.