The results showed that biochar and hydrochar can promote cumulative methane yield by 15% to 29%.  However, there was no statistical significance (p > 0.05) between hydrochar and biochar produced at different temperature on methane production.  16S rRNA gene sequencing and bioinformatics analysis showed that biochar and hydrochar enriched microorganism that might participate in direct interspecies electron transfer (DIET) such as Pseudomonadaceae, Bacillaceae, and Clostridiaceae.  The the surface properties of the modified biochar were characterized with BET, Raman, FTIR and XPS. 
Biochar
The results showed that biochar and hydrochar can promote cumulative methane yield by 15% to 29%.  However, there was no statistical significance (p > 0.05) between hydrochar and biochar produced at different temperature on methane production.  16S rRNA gene sequencing and bioinformatics analysis showed that biochar and hydrochar enriched microorganism that might participate in direct interspecies electron transfer (DIET) such as Pseudomonadaceae, Bacillaceae, and Clostridiaceae. 
Hydrochar
16S rRNA gene sequencing and bioinformatics analysis showed that biochar and hydrochar enriched microorganism that might participate in direct interspecies electron transfer (DIET) such as Pseudomonadaceae, Bacillaceae, and Clostridiaceae. 
16S rRNA gene sequencing
However, there was no statistical significance (p > 0.05) between hydrochar and biochar produced at different temperature on methane production.  The the surface properties of the modified biochar were characterized with BET, Raman, FTIR and XPS. 
BET
The the surface properties of the modified biochar were characterized with BET, Raman, FTIR and XPS. 
Raman
The the surface properties of the modified biochar were characterized with BET, Raman, FTIR and XPS. 
FTIR
The the surface properties of the modified biochar were characterized with BET, Raman, FTIR and XPS. 
XPS