Improving fungal decay resistance of less durable sapwood by impregnation with Scots pine knotwood and black locust heartwood hydrophilic extractives with antifungal or antioxidant properties

Viljem Vek (Author), Angela Balzano (Author), Ida Poljanšek (Author), Miha Humar (Author), Primož Oven (Author)

Abstract

The antifungal assay confirmed that knotwood extractives of Scots pine inhibit the growth of wood decay fungi. Heartwood extracts of black locust were found to be much stronger free radical scavengers than the extracts of Scots pine. The extracts were deposited in the lumina and on the wall surface of cells in the impregnated sapwood. Impregnation of the sapwood blocks with Scots pine and black locust extracts reduced the fungal decay of wood. Objectives: Hydrophilic extracts of Scots pine knotwood and black locust heartwood were chemically analyzed, tested for antifungal and antioxidant properties and used for impregnation of beech and Scots pine sapwood. Materials and Methods: Scots pine knotwood and black locust heartwood were extracted, and obtained hydrophilic extractives were chemically analyzed. Extracts were analyzed for antifungal properties with the in vitro well-diffusion method. The free radical scavenging activity of wood extracts was measured colorimetrically. The retention of the extracts in the impregnated sapwood blocks was evaluated with microscopy and gravimetry. A decay test was performed with the mini block test. Results: Almost half of both Scots pine knotwood and black locust heartwood hydrophilic extracts obtained were described by phenolic compounds. The extracts were deposited in the lumina of cells and on the cell wall surface. Extractives of Scots pine knotwood had good inhibitory properties against white- and brown-rot fungi. On the other hand, extractives of black locust heartwood were found to be good radical scavengers, better than knotwood extractives of Scots pine. The extracts of Scots pine knotwood and black locust reduced the fungal decay of the tested sapwood blocks. Conclusions: The results of this research show that the less-valued knotwood of Scots pine and heartwood of black locust are a potential source of antifungal and antioxidant agents for bio-based wood preservatives.

Keywords

Pinus sylvestris;Robinia pseudoacacia;hidrofilni ekstraktivi;impregnacija lesa;inhibicija rasti gliv;lovljenje prostih radikalov;odpornost proti razkroju;hydrophilic extractives;wood impregnation;fungal growth inhibition;radical scavenging activity;decay resistance;

Data

Language:	English
Year of publishing:	2020
Typology:	1.01 - Original Scientific Article
Organization:	UL BF - Biotechnical Faculty
UDC:	630*813
COBISS:	29712643
ISSN:	1999-4907
Views:	191
Downloads:	56
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	Slovenian
Secondary keywords:	Pinus sylvestris;Robinia pseudoacacia;hidrofilni ekstraktivi;impregnacija lesa;inhibicija rasti gliv;lovljenje prostih radikalov;odpornost proti razkroju;
Type (COBISS):	Article
Pages:	23 str.
Volume:	ǂVol. ǂ11
Issue:	ǂiss. ǂ9
Chronology:	2020
DOI:	10.3390/f11091024
ID:	14344595