米根霉发酵产L-苹果酸的工艺优化

以米根霉（Rhizopus oryzae）突变株CICC40503-JST为菌种，葡萄糖为碳源，对其发酵工艺及葡萄糖代谢途径进行初步研究，从而提高L-苹果酸的产量。采用单因素试验和响应曲面法（Box-Behnken设计）对培养基和发酵条件进行优化，研究发酵罐实验对产酸的影响。结果获得最佳培养基配方为：葡萄糖100 g/L、(NH4)2SO4 4.0 g/L、MgSO4 0.3 g/L、FeSO4?7H2O 0.025 g/L、KH2PO4 0.5 g/L、ZnSO4 0.1 g/L、CaCO3 80 g/L。发酵条件较好组合为：发酵设备为Sartorius发酵罐、发酵温度32 ℃、通气量0.20 L/（min·L）、转速500 r/min、孢子悬浮液单独培养48 h、发酵进行48 h后添加培养基进行补料发酵，发酵周期为72 h、L-苹果酸的产量为57.71 g/L。结论：米根霉能够较好地利用葡萄糖发酵产L-苹果酸，其产量得到明显提高。

Optimization of Medium Components and Fermentation Conditions for L-Malic Acid Production by Rhizopus oryzae

In order to improve the yield of L-malic acid, the fermentation process and glucose metabolism pathways for
Rhizopus oryzae mutant strain CICC40503-JST were preliminary studied in this paper. The culture medium and fermentation
conditions were optimized by using combination of single factor method and response surface methodology with central
composite design. Meanwhile, the production and possible metabolic pathway of L- malic acid were explored using
stirred tank fermentor. The results showed that the optimal medium composition for malate production were determined
as follows: glucose, (NH4)2SO4, MgSO4, FeSO4·7H2O, KH2PO4, ZnSO4 and CaCO3 100, 4.0, 0.3, 0.025, 0.5, 0.1 and
80 g/L, respectively. The fermentation conditions were optimized to be spore suspension incubation for 48 h and subsequent
fermentation in a Sartorius fermentor at 32 ℃ for 48 h followed by another 24 h after addition of fresh culture medium with
a ventilation rate of volume of 0.20 L/(min·L) and a rotation rate of 500 r/min. Under these conditions, the yield of L-malic
acid was 57.71 g/L. In conclusion, the yield of malate could be improved significantly through effective utilization of glucose
under the optimized culture conditions.