Abstract: A strain of red pigment fungi RJL03 was isolated from the medicinal plant Rehmannia glutinosa Libosch by tissue block separation method. Monascus sanguineus was identified according to morphological characteristics and rDNA ITS1-5.8S-ITS2 sequence analysis.The extraction process conditions of RJL03 red pigment were explored by Response Surface Methodology (RSM).On the basic of single factor tests,the organic solvent Ultrasonic-Assisted Extraction (UAE) process of red pigment in the strain was optimized using the Box-Behnken design (BBD),with the optical density of the extract as an index.The experiment manifests that the extraction of pigment has its maximum absorption wavelength at 515nm.The optimal extraction temperature was 70 ℃,the extraction time was 34 min,and the ethanol concentration was 50%(V/V).Under these conditions,the red pigment in the strain was extracted after fermentation,and comparable to the amount of pre-optimized extraction increased by about 1.5 times.

Key words: Rehmannia glutinosa  Libosch, endophytic fungi, red pigment, ultrasonic-assisted, Monascus; Monascus sanguineus