is both bactericidal and the main oxidant responsible for lignin degradation reaction catalyzed by manganese peroxidase (MnP) and lignin peroxidase (LiP). Thus, H 2 O 2 treatment of corn stalk and the implementation of solid-substrate fermentation (SSF) is possible to increase the removal rate of lignin from stalk in the process of SSF and after SSF, while avoiding the need to sterilize the raw materials. To demonstrate this approach, SSF was initially carried out using corn stalk pretreated with different concentrations of H 2 O 2 as a substrate. A. oryzae was found to grow well in the 3% H 2 O 2 -pretreated corn stalk. H 2 O 2pretreated corn stalk showed increased MnP and LiP synthesis and disintegration of lignin, but inhibited cellulase synthesis and cellulose degradation. Production of the SSF (200 g) on the 10th day was hydrolyzed in the presence of additional 600 mL different concentration of H 2 O 2 aqueous solution. The total removal of lignin (73.15%) of hydrolysis for 10 h at 3% H 2 O 2 solution was highest and far higher than that at the 12th day, as achieved by conventional SSF. Applying this strategy in practice may shorten the time of lignin degradation, increase the removal of lignin, and decrease the loss of cellulose. Thus, this study has provided a foundation for further study saccharification of corn stalk.

Fresh biomass of Aspergillus oryzae (A. oryzae) CGMCC5992 can effectively remove gallic acid from aqueous solution. To improve the removal rate of gallic acid, this study first identified the important factors affecting the removal rate of gallic acid with univariate analysis, and then used four-factor and three-level Box-Behnken design (BBD) with the removal rate of gallic acid as response value, to obtain the optimum conditions for the removal of gallic acid as follows: 6.95 h treatment time, pH 3.70, 7.07 g/L mycelium volume, and 120.64 mg/L initial concentration of gallic acid. Under such optimized condition, the removal rate of gallic acid approached 99.21 %. HPLC-MS analysis proved that the gallic acid in aqueous solution was completely removed by A. oryzae, rather than being metabolized into its derivatives. Scanning electron microscopy (SEM) indicated that the biomass morphology and surface structure of A. oryzae changed after the adsorption of gallic acid. Thus, the present study has provided an optimal condition for A. oryzae removal of gallic acid in water.

This study aims to optimize the medium for xylanase activity by a newly isolated strain of Rhizopus stolonifer JS-1008 (R. stolonifer JS-1008) under solid-state fermentation (SSF) on corncob. Four quantitative variables impacting the enzyme activity were selected through onefactor-at-a-time design. They were nitrogen source, initial moisture content (IMC), inorganic salt, and surface active agent. In addition, the interaction among these factors was further investigated by response surface methodology (RSM). Statistical analysis revealed that among these factors, IMC and urea significantly affected the xylanase activity. Our data indicate that the optimal medium contains (g/g dry corncob): urea, 0.15; ZnSO 4 , 0.022; Tween-80, 0.08; IMC, 3. Under the optimal condition, the xylanase activity reached its maximum, 13.90 U/g dry substrate (DS), on the 10 th day of fermentation. This work provides a new potential strain to synthesize xylanase for biofuel production.

Direct discharge of vinasse from the distillery industry causes resource wasting and environmental destruction due to its mass of organic components. Aspergillus oryzae CGMCC5992 is capable of degrading the organic substrates of wastewater. One-factor-at-a-time design was adopted to select the most important nutrients influencing the degradation of organic materials of vinasse. Box-Behnken Design (BBD) with Design-Expert (8.0.4) was used to develop mathematical model equations, study responses, and optimize concentrations of the key nutrients to improve the degradation efficiency. The optimized medium containing 0.3 g/L urea, 20.73 mg/L ZnSO(4), and 19.79 mg/L vitamin B(6) was supplied to 10-times diluted vinasse; under the optimal condition, a decrease of chemical oxygen demand (COD) from 4,635 to 323 mg/L in vinasse was achieved in 5 days. The reduction of vinasse COD after the optimization of nutrient condition in this study is more significant than those reported previously.