Abstract: Crude solid vanillin-containing material is precipitated from a solution obtained by biotransformation, and purified by a process comprising contacting it with a purification fluid selected from (a) a liquefied gas whose pressure exceeds its critical pressure and whose temperature is below its critical temperature; (b) a supercritical fluid; (c) a gas. The fluid is preferably liquid carbon dioxide. The temperature is maintained below 25°. The product may be further purified by treatment with CO2 in a fluid bed drier. The crude material is preferably one precipitated from a solution resulting from biotransformation of ferulic acid. A new strain of Amycolatopsis capable of generating high concentrations of vanillin with minimal odoriferous by-products (e.g. guaiacol) is also disclosed.