Enhancing Methane Production from Lignocellulosic Biomass by Steam-Explosion Pretreatment and Bioaugmentation

Biogas production from lignocellulosic biomass is considered challenging due to the recalcitrant nature of the biomass. The team of Daniel Girma Mulat from the Norwegian University of Life Sciences applied steam-explosion (SE) pretreatment (210 °C and 10 min) to reduce the recalcitrance of birch. The team also performed bioaugmentation, the addition of other cultured microorganisms. They added Caldicellulosiruptor bescii to the anaerobic digestion (AD) to enhance methane production from steam-exploded birch.

The combined SE and addition of C. bescii enhanced methane yield by up to 140% compared to untreated birch, while SE alone contributed to the major share of methane enhancement by 118%. The best methane improvement was observed in bottles fed with pretreated birch and with lower dosages of C. bescii. The maximum methane production from steam-exploded birch with dosages of C. bescii increased significantly compared to the yield from untreated birch.

The bioaugmentation was effective for increasing the initial methane production rate of pretreated birch, yielding 21–44% more methane than pretreated birch without bioaugmentation.

These results demonstrate the potential of combined SE and bioaugmentation for enhancing methane production from lignocellulosic biomass.