High Efficiency Hypocrellin Production by a Novel Mutant Isolated from Shiraia bambusicola

The fungus Shiraia bambusicola GZ19M1 is biotechnologically important due to its ability to biosynthesis the pigment hypocrellins. Results showed that ethyl methane sulfonate (EMS) was effective mutagenic agent for strain and potentially produced large numbers of random mutations broadly and uniformly over the whole genome to generate unique strains. Wild-type cultures of S. bambusicola GZ19 were subjected to EMS (80 mM) induction targeted at approximately 20% spores’ survival. When surviving spores were selected in sufficient numbers and cultured on PDA medium for 7 d at 26℃, five novel mutagenized S. bambusicola strains were obtained. A mutant GZ19M1 that exhibited an activity of more than two times over the wild strain was obtained. Also, batch experiments were carried out to achieve the suitable conditions for hypocrellin. Glucose and rice extract were the most favorable carbon and nitrogen sources for hypocrellin production by submerged culture of S. bambusicola GZ19M1, and initial glucose and rice extract concentrations were at 35 and 250 g/L, respectively. The optimal surfactant were found to be 0.008 V/V Tween 80, it was added into cultivation medium at 24 h. Hypocrellin concentration reached 498.89 mg/L under optimal nutritional conditions, an increment of about 8.70 times of hypocrellins production was observed compared with that of in non-optimized medium by the wild strain.