Optimization of exopolysaccharide production from Armillaria mellea in submerged cultures.

AIMS

To study the optimization of submerged culture conditions for exopolysaccharide (EPS) production by Armillaria mellea in shake-flask cultures and also to evaluate the performance of an optimized culture medium in a 5-l stirred tank fermenter.

METHODS AND RESULTS

Shake flask cultures for EPS optimal nutritional production contained having the following composition (in g l(-1)): glucose 40, yeast extract 3, KH(2)PO(4) 4 and MgSO(4) 2 at an optimal temperature of 22 degrees C and an initial of pH 4.0. The optimal culture medium was then cultivated in a 5-l stirred tank fermenter at 1 vvm (volume of aeration per volume of bioreactor per min) aeration rate, 150 rev min(-1) agitation speed, controlled pH 4.0 and 22 degrees C. In the optimal culture medium, the maximum EPS production in a 5-l stirred tank fermenter was 588 mg l(-1), c. twice as great as that in the basal medium. The maximum productivity for EPS (Q(p)) and product yield (Y(P/S)) were 42.02 mg l(-1) d(-1) and 26.89 mg g(-1), respectively.

CONCLUSIONS

The optimal culture conditions we proposed in this study enhanced the EPS production of A. mellea from submerged cultures.

SIGNIFICANCE AND IMPACT OF THE STUDY

The optimal culturing conditions we have found will be a suitable starting point for a scale-up of the fermentation process, helping to develop the production of related medicines and health foods from A. mellea.