Enhanced biomethane production from Miscanthus lutarioriparius using steam explosion pretreatment

• Miscanthus is a potential feedstock for biomethane production.
• Five different steam explosion conditions were studied on Miscanthus.
• Resulted indicated hemicellulose degradation and increased crystallinity.
• Over 49% enhancement in BMP was achieved as compared with the raw substrate.

Steam explosion pretreatments was used to improve the anaerobic biodegradability of Miscanthus lutarioriparius (M. lutarioriparius). The pretreatments were carried out under five different conditions: L1 (0.5 MPa 153 °C 5 min), L2 (1.0 MPa 180 °C 5 min), L3 (1.5 MPa 198 °C 3 min), L4 (1.5 MPa 198 °C 5 min) and L5 (1.5 MPa 198 °C 10 min). The biochemical methane potential (BMP) of raw M. lutarioriparius sample was 181.7 ± 10.7 mLCH4/gVS. After applying the steam explosion pretreatments under the five aforementioned levels, the BMP value of pretreated samples increased by 5.9%, 19.9%, 51.3%, 49.7% and 49.8% respectively. The Fourier Transform Infrared Spectroscopy (FTIR) of raw and pretreated M. lutarioriparius, revealed the disintegration of the biomass structure. Furthermore, scanning electron microscopic (SEM) images revealed the apparent disruption of the recalcitrant structure of the M. lutarioriparius. The structural changes in M. lutarioriparius observed via FTIR and SEM after steam explosion therefore led to the improvement in biomethane potential and gas production rate. BMP results indicate that M. lutarioriparius could be effectively converted to bioenergy in forms of biogas after steam explosion pretreatment.