Enhanced oxalic acid production was investigated in semi-solid state fermentation of methanol-resistant
Aspergillus nigerusing corncob.Methanol-resistantA. niger was selected fromthe sector of colony showing
phenotypically intact growth despite 5% methanol in solid medium (PDA) and finally obtained through
the adaptation process for 22 weeks. Oxalic acid production of methanol-resistant A. niger was dramatically
enlarged in liquid culture (CZB) by 9.14 folds compared with that of parent cells. Semi-solid state
fermentation of corncob has been developed for the application of low-cost and environment friendly
biomass waste to organic acid production. Oxalic acid production was dependent of inoculum size and
initial substrate concentration, which was optimized at 106 spores/g dry weight and 5% (w/v) corncob in
0.1 N NaOH solution, respectively, which led to the maximum productivity (123.0 g/kg dry weight of corncob).
Results demonstrate that methanol-resistant A. niger has great potentials for oxalic acid production
from biomass.