EXTRACTION OF ANTIMICROBIAL COMPOUNDS FROM WOOD USING SUPERCRITICAL CO_2

摘要

A new anti-microbial product, totarol, has been extracted using supercritical CO_2 from the heartwood of Totara, an indigenous tree of New Zealand. Totarol is an effective antimicrobial agent against gram-positive bacteria, and also has preservative and antioxidative properties It has recently been incorporated into natural product-based cosmeceuticals and nutraceuticals. Extraction trials have been performed at a laboratory through to a production scale, and include measurements of the totarol solubility, purification of the extract, effect of particle size on extraction rate and yield, and solution of scale-up problems. Two extracts are obtained: a totarol rich fraction, and an essential oil/water rich fraction. While extraction of totarol and related compounds from the wood is straightforward, recovery of the extract and operation at a production scale is difficult. Totarol extract is solid, and has a tendency to block pipes and valves. Novel solutions to the blockage problems have been found, which generate an additional product. A method has also been found to generate fine particles of totarol.