Supplementation of the key metabolite, alpha-(Z)-acaridiol, to stirred-tank cultured Pleurotus ostreatus was used to demonstrate that integrated in situ product recovery resulted in high conversion rates and quantitative separation of the target product perillene from the nutrient medium. The conversion of beta-myrcene by P. ostreatus was scaled-up from shake-flasks into a controlled, stirred tank bioreactor equipped with gas stripping and adsorption on a polystyrene fixed bed. The formation of the attractive flavour compound perillene was measured daily using standard controlled capillary gas chromatography. The formation of alpha-(Z)-acaridiol was the metabolic bottleneck of the conversion of beta-myrcene to perillene. Efficient in situ recovery of the volatile product enabled quantitative separation of the pure flavour compound. Appropriated bioprocessing, i.e. in situ separation of product, steadily shifted the metabolic equilibria and thus accomplished high conversion rate and pure product.