Abstract: The response surface methodology was used to optimize the culture conditions for furfural production by Aspergillus niger (A. niger). The culture conditions of carbon source, nitrogen source, pH-value, temperature, and shaker speed were screened by the single-factor test. The key factors affecting culture conditions were studied by the Plackett-Burman (PB) test. Also, the steepest climbing experiment was used to determine the response center point of key factors, and then the optimal culture conditions were obtained by Box-Behnken method that performed response surface analysis. In this study, glucose and urea as the carbon and nitrogen source, the pH-value (7.0), temperature (26℃), and rotation speed (150r/min) were the best in the single-factor test. In the PB design experiment, glucose, urea, and pH-value were the significant factors affecting for the culture of A. niger. The optimal culture conditions were obtained by the steepest climbing experiment, the Box-Behnken method and RSM. Our results revealed that the optimized culture conditions were glucose 80g/L, urea 3.03g/L, pH-value 8.2, temperature 26℃, and rotation speed 150r/min respectively. The verification test was carried out under the optimal culture conditions. The content of furfural in A. niger was determined by high performance liquid chromatography (HPLC) after culturing 3 days, which reached 4.094μg/mL, increased by 20.2% compared to that of the pre-optimization (3.407μg/mL). Collectively, the results can provide theoretical references basis for the optimization of culture conditions for furfural production by A.niger.

Key words: Aspergillus niger, furfural, single factor, high-performance liquid chromatograph, response surface methodology