Optimization of pneumocandin B0 production by filamentous fungus Glarea lozoyensis SIIA-F1108

Abstract:

[Objective] The culture media for the production of pneumocandin B0 by the filamentous fungus Glarea lozoyensis SIIA-F1108 were optimized using the response surface methodology (RSM). The nitrogen source of the culture was optimized to reduce the volume concentration of mycelium and improve the level of dissolved oxygen in fermentation process. [Methods] Through Plackett-Burman design and RSM, the factors that had significant effects on the production of pneumocandin B0 were screened. Afterwards, the path of steepest ascent and the Box-Behnken design were adopted for further optimization, and the optimal concentration levels and the relationships among these factors was found out by quadratic regression model equation with Design-Expert statistic methods. The high-yield and low-viscosity of fermentation medium was obtained by carrying out the whole factor experiment with nitrogen source components. [Results] Mannitol, proline and glucose were found to have greatest influence on the production of pneumocandin B0, and the optimal concentrations were 167.3, 26.1 and 28.5 g/L, respectively. Under the optimal conditions, the production of pneumocandin B0 reached 1 840 mg/L in three baches of shake flask experiments, with an increase of 42% compared with the ordinary culture. The pneumocandin B0 production of 100 L fermentor achieved 1 980 mg/L under the optimal conditions. The viscosity of the fermentation broth was reduced by partly replacing the cottonseed meal with (NH4)2SO4. [Conclusion] The production of pneumocandin B0, which was in agreement with the prediction, was increased by 42% compared with the previous condition. The RSM method was effective for optimizing the composition of medium for the production of pneumocandin B0 by filamentous fungus Glarea lozoyensis SIIA-F1108. After replacing the cottonseed meal with (NH4)2SO4, the viscosity of the fermentation broth was reduced and the level of dissolved oxygen was improved in fermentation process.