Abstract: The mannitol content of the mycelium of Paecilomyces tenuipes and its culture medium was analyzed colorimetrically at 412 nm. The effects of extraction solvent, temperature and time on extraction yield of mannitol were investigated to optimize the extraction conditions. The best results of mannitol extraction were achieved by using distilled water to extract Paecilomyces tenuipes mycelium at 60 ℃ and extract its culture medium at 100 ℃ for 60 min both. Under these conditions, the recovery rate of mannitol from Paecilomyces tenuipes mycelium was 99.94% with a RSD of 0.74%, the precision RSD was 0.80% and a good stability of the OD value at 412 nm was found within 60 min. In the case of mannitol extraction from the culture medium, the recovery, RSD and precision RSD were 99.79%, 1.17%, and 1.00%, respectively, and the OD value at 412 nm also showed a good stability within 60 min.

Key words: Paecilomyces tenuipes, mannitol, colorimetry, mycelium, medium