Study On Optimization Of Fermentation Condition Using Aureobasidium Pullulans HP-2001

Aureobasidium pullulans is a kind of multi-morphology fungi. Pullulan is a major polysaccharide produced by strains of Aureobasidium pullulans. It has the potential multi-utilization. In the experiment, pullulan fermentation strain was selected, both the media and fermentation process was optimized.1. Stain selectionBase on rotary shaker, the pullulan productivity by the 6 strains were inspected. Different concentration of rice hull and rice bran was used as carbon source to detect the 6 strains' cellulose decompose activity primary. Glucose was also used as carbon source to compare with rice hull and rice bran.The cell growth and pullulan production couldn't be detected when rice hull was carbon source. The strains secreted a little pullulan in rice bran medium, although can not satisfied the requirement in industry. Aureobasidium pullulans KCCM60122 and HP-2001 secreted more pullulan than other 4 strains, especially in 50.00g/L glucose medium, The pullulan production were 14.35å’Œ15.48g/L seperately, and the pullulan production of other 4 strains was less than 5g/L.2. Optimization of fermentation condition using Aureobasidium pullulans HP-2001The single factor and orthogonal experiment was carried out to optimize the fermentation condition. The optimal culture medium for cell growth was also obtained(g/L): glucose 100.00g/L, yeast extract 2.50 g/L, K₂HPO₄2.50g/L, NaCl 1.00g/L, MgSO₄·7H₂O 0.10g/L, (NH₄)₂SO₄2.40g/L, initial pH6.0, and the optimal temperature was 30℃. The optimal culture medium for pullulan production was obtained(g/L): glucose 100.00g/L, yeast extract 2.50 g/L, K₂HPO₄ 2.50g/L, NaCl 0.25g/L, MgSO₄·7H₂O 0.05g/L, (NH₄)₂SO₄ 0.30g/L, initial pH6.0, and the optimal temperature was 25℃。3. Optimization of fermentation process using Aureobasidium pullulans HP-2001 The optimization of aeration, agitation was carried out in 7L fermentor and inner pressure was carried out in 100L fermentor. The results showed the best aeration and agitation was 1.00vvm and 400r/min, the best inner pressure was 0.40kgf/cm².