APPLICATION OF A TWO-STAGE AGITATION SPEED CONTROL STRATEGY TO ENHANCE YELLOW PIGMENTS PRODUCTION BY MONASCUS ANKA MUTANT

Abstract

Monascus anka mutant strain was isolated using conventional mutation techniques in our laboratory. In our previous study, strain Monascus anka mutant showed high yield of yellow pigments with the characteristics of high protein adhesion, thermal stability, and wide-pH stability. This work focused on the agitation optimization in a 5 L fermentor of strain Monascus anka mutant and two stage agitation speed control strategy was operated as follows: the agitation speed was 400 r/min to improve the Monascus growth and yellow pigments production before culturing 96 hour and then 300 r/min was carried out to extend the time of yellow pigment production with efficient using substrate. The yield of monascus yellow pigments reached 149.43 OD, which was 49.37%，49.25%，35.56%，18.73%, and 41.01% higher than that of 250 r/min, 300 r/min, 350 r/min, 400 r/min, and 450 r/min fermentation, respectively. The maximum specific growth rate (µmax) and the maximum specific production rate of yellow pigments (qy) reached 0.0528 h-1 and 0.2177 OD.g-1.h-1, respectively. Specific growth rate (µ) maintained higher than 0.01 h-1 from 6 hours to 54 hours, and qy could maintain at 0.10 OD.g-1.h-1 from 24 hour to 66 hour, which could not be obtained by single agitation control. The data of this work could contribute to making the industrial production of Monascus yellow pigments feasible.