Modification of Loblolly Pine Chips with Ceriporiopsis subvermispora Part 1: Effect of Fungal Treatment

Abstract

The effect of treating loblolly pine (Pinus taeda) chips with the fungus Ceriporiopsis subvermispora was investigated by assessing the wood changes at 2 and 4 weeks incubation relative to a control (no fungal treatment). Scanning electron microscopy indicated that during the first 2 weeks of colonization, C. subvermispora had grown over the surface of the chips and also within ray cells. A mass loss of 5% occurred after 2 weeks, 6% after four weeks. The extractives were reduced 23% in the first 2 weeks of fungal treatment and 32% after 4 weeks. Lignin loss was statistically insignificant at 2 weeks but reached 8% of the original lignin after 4 weeks. The carbohydrate content of the treated wood showed no significant differences from the control after 2 weeks and only minor losses after 4 weeks. The fraction of the wood soluble in 1% NaOH was 14.9% at 2 weeks compared to 11.5% for the control chips and increased to 18.8% after 4 weeks. This indicated only a mild decay due to the fungal treatment. At 2 weeks of fungal treatment, the lignin phenolic hydroxyl content was not significantly different from the control. However, after 4 weeks of treatment the phenolic hydroxyl groups increased by 14%. Small increases in the average pore size of the wood occurred with incubation time, including a broadening in the range of pore sizes.

Keywords:

• Ceriporiopsis subvermispora
• white‐rot fungus
• loblolly pine
• carbohydrates
• lignin
• extractives
• pore size