Optimization and antioxidant activity of polysaccharides produced by actinomycetes in complex flora cultivated on a ground corn straw medium

In this study, corn straw polysaccharides (CSPs) were successfully isolated from a corn straw medium by cellulose-degrading actinomyces in complex flora. Response surface methodology was applied to optimize the extraction conditions. Under the optimum conditions of fermentation time of 12 days and initial corn straw concentration of 50 g/L, the polysaccharide yield reached 2159.23 mg/L. Fourier transform infrared spectroscopy, gas chromatography, and scanning electron microscopy were used to analyze the CSP structure. The results showed that the CSPs consisted of rhamnose, arabinose, xylose, glucose, mannose, and galactose with a molar ratio of 1.0:13.4:16.8:3.0:2.7:8.4, respectively. In addition, the CSP surface was covered with irregular spherical particles. The antioxidant assays suggested that the CSPs have strong scavenging effects of 87.33% and 69.95% on hydroxyl and 1,1-diphenyl-2-picrylhydrazyl radicals at concentrations of 0.80 and 0.40 mg/mL, respectively. Further, CSP demonstrated its potential for development as a natural antioxidant. This work offered an environmentally microbial process for the extraction of polysaccharide from low-cost corn straw.

Automated summary

Corn straw polysaccharides (CSPs) were successfully extracted from corn straw by cellulose-degrading actinomyces in a complex microbial community. The optimized extraction conditions resulted in a high polysaccharide yield, and the structure of CSPs was analyzed using various techniques. Additionally, CSPs showed strong antioxidant activity and potential as natural antioxidants.