Abstract: Rhizopus arrhizus was applied in fumaric acid fermentation with unhydrolyzed raw tapioca flour as the carbon source. The effects of tapioca flour fineness, the calcium carbonate amount, oxygen vectors additive and rotation speed in flasks on fumaric acid prodution from raw tapioca flour by Rhizopus arrhizus was investigated. The fermentation processes of glucose and raw tapioca flour as two carbon sources in flasks were compared. A maximum fumaric acid production of 46.36 g/L in flasks was obtained with a productivity of 0.32 g/L·h. Using a selfmade 2.5 L airlift reactor(culture temperature 30℃, aeration rate 154 vvm, the filling volume 1.3 L), the fumaric acid production was up to 42.32 g/L, with a productivity of 0.29 g/L·h.

Key words: Rhizopus arrhizus, fumaric acid, raw tapioca flour, simultaneous saccharification, airlift reactor