Insight into the Enzymatic Mechanism of Straw Carbon Source and Its Denitrification Availability

Abstract

The application of an enzymatic straw carbon source (SCS) to a denitrifying system was a promising method for recycling straw waste. However, the total components of an enzymatic SCS, and their effectiveness for denitrification, are still controversial, which hinders its application to denitrifying. In this study, we combined silylation derivatization and GC-MS technology to conduct a comprehensive analysis of the enzymatic SCS components, and further identified the availability of the components in nitrogen removal. The addition of cellulase could improve both the carbon release amount (increase by 300%) and its effectiveness (66% to 83.7%). The components in both the SCS and enzymatic SCS could be divided into three categories: saccharides, VFAs and aromatic structures. Both saccharides and VFAs were effective for denitrifying and accounted for 86.8% of the enzymatic SCS. Most of the invalid components (aromatic structure) belonged to benzoic acid derivatives which originated from the fragments of straw lignin. In summary, the parameters regarding the components, manufacture and availability of the enzymatic SCS were figured out in this study, laying the foundation for straw waste application to the denitrifying process.