Abstract: A systematic investigation was carried out to improve the productivity of fumaric acid producing strain by UV irritation and bioprocess optimization. During the selection procedure, a simple way of screening for high-yield fumaric acid producing strain was developed and evaluated, in which, area ratio of area of colored ring to that of colony was designed as an indicator.
Strain improvement has been conventionally achieved through mutation and selection. A fumaric acid over-producing strain mutant, Rhizopus oryzae , was isolated by mutagenizing the parent strain by UV mutagenesis. Starting with an optimized concentration of 29.8 g/l glucose, the mutant Rhizopus oryzae ZJU11 produced 50.9 g/l fumaric acid in shaking-flask fermentation , which were 70.8% higher than that of the parent strain produced respectively.
The influences of nitrogen sources, carbon sources, concentration of CaCO3 and its addition method CaCO3 in culture medium on fumaric acid production by the mutant Rhizopus oryae ZJU11were investigated.
Keywords：Fumaric acid; Rhizopus oryzae; UV irritation; optimization; Nystatin
