Anti-Fungal Properties Of The Pyroligneous Liquors From The Pyrolysis Of Softwood Bark

Daniel Mourant, Dian-Qing Yang, Xiao Lu, Christian Roy

Abstract


Thermal decomposition of balsam fir and white spruce mixed bark residues at 450°C and under vacuum (<20 kPa abs.) results in high yields of pyroligneous liquors rich in phenols. The pyrolytic aqueous condensate fractionation in four distinct parts was accomplished by a liquid-liquid extraction method. Each fraction was tested for its anti-fungal properties.

Petri dish bioassays were conducted using two brown-rot fungi (Postia placenta and Gloeophyllum trabeum) and two white-rot fungi (Irpex lacteus and Trametes versicolor). The fraction obtained by ethyl ether extraction and containing organic acids, phenols, and phenol-derivatives (3.0% by weight), benzenediols, (3.9% by weight) and a variety of other products (quinones, furans, etc.), produced the largest inhibition of the decay fungi, while the neutral fraction, leftovers of the precipitation of the aforementioned fraction, showed no inhibition effects. T. versicolor was most sensitive to these fractions, while I. lacteus was the least. The addition of CuSO4 to the water-soluble organic compounds improved antifungal activity.


Keywords


Pyrolysis;aqueous phase;phenols;decay;bark;bioassays;wood preservation

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