Improvement of biovanillin production with two-stage pH control strategy from lemongrass leaves hydrolysates using Phanerochaete chrysosporium ATCC 24725 in batch culture

The biovanillin production was influenced by varying the culture pH via single control strategy conducted by separate experiments during the fermentation processes. Highest biovanillin production (124 mg/L) with 32% molar yield at culture pH 6.0 from the one-stage control method was observed. Specific growth rates (μ) of the Phanerochaete chrysosporium and biovanillin production decreased by decreasing the culture pH from 6.0 to 3.5, which indicated that lower culture pH was not adequately apposite for biovanillin production using Phanerochaete chrysosporium in a 2-L stirred tank bioreactor. The development of two-stage control strategies had improved the biovanillin production (131 mg/L) and cell concentration (13.0 g/L) by about 6 and 5%, respectively. Therefore, the most influential control strategy for higher biovanillin production was discovered not to control the culture pH of the fermentation during active growth phase of the Phanerochaete chrysosporium, while the production phase should be controlled at pH 6.0.