| dc.description.abstract | Vanillin (3-methoxy-4-hydroxybenzaldehyde) is one of the major constituents of ‘‘natural vanilla’’ flavor responsible for its characteristic aroma and is the most widely used flavor ingredient in the cosmetics and food industries. The price of ‘‘natural’’ vanillin is very high compared to the chemically synthesized form, mainly due to the limited availability of vanilla pods, which cannot meet the demand of the growing global market for natural vanillin, search for attractive alternative resource is important. Fermentation products are from microorganisms, which are generally considered as natural products. However, only vanillins biotechnologically produced from ferulic acid are considered as food-grade additives by most food safety control authorities worldwide. Furthermore, ferulic acid is rich in agricultural wastes. The microbial fermentation produces high value-added products from inexpensive feedstock such as agricultural wastes, so the cost of production is relatively low, and is more environmental friendly. It is consistent with the concept of sustainable development.
In microbial fermentation procedures, environmental temperature will greatly affect not only the physiological status but also the behavior of fermentation. Ergo, the aim of this study was to investigate the effects of culture temperature on the production of vanillin from ferulic acid by Amycolatopsis thermoflava. The results of experiments showed that the maximum biomass concentration when the culture temperature is 45℃ at the initial stage of fermentation. The optimal vanillin production temperature was 35℃. In this optimal operation, the yield and productivity of vanillin were the highest among other operations, the production of vanillin was 458 mg/L, which was about two hundred and nine percent higher than that obtained from the operation of which culture temperature was fixed at 45℃. Therefore, using the two-stage culture temperature operation, the first stage culture temperature was set at 45℃ to cause more biomass, and then the second stage culture temperature was shifted to 35℃ to enhance the production of vanillin. In this operation, the production of vanillin was 681 mg/L, which was about forty nine percent higher than that obtained from the operation of which culture temperature was fixed at 35℃. As a result, adjusting the culture temperature can make the product formation approaching the ideal type, thereby improving and enhancing the fermentation performance. | en_US |