Optimisation of riboflavin production by the marine yeastCandida membranifaciens subsp.flavinogenie W14-3 using response surface methodology

In this study, the optimisation of the process parameters for riboflavin production by the marine yeast strainCandida membranifaciens subsp.flavinogenie W14-3 was carried out using response surface methodology (RSM) based on Central Composite Designs (CCD). We found that the amount of xylose, pH, temperature and shaking speed had great influence on riboflavin production by strain W14-3. Therefore, a response surface design was used to evaluate the influence of the four factors on the riboflavin production. Then, five levels of the four factors above were further optimised using a Central Composite design. Finally, the optimal parameters for the riboflavin production were obtained with RSM. Under the optimised conditions (the production medium containing 2.0% xylose, pH 4.5, temperature 28°C and shaking speed 170 rpm), 22 μg ml−1 of riboflavin was reached in the culture of strain W14-3 within 54 h of fermentation whereas the predicted riboflavin yield of 22 μg ml−1 was derived from RSM regression.