Enzymatic pretreatment of steam-exploded birch wood for increased biogas production and lignin degradation

Seyedbehnam Hashemi,Prajin Joseph,Antoine Mialon,Størker Moe,Jacob J Lamb,Kristian M Lien

doi:10.1016/j.biteb.2021.100874

Seyedbehnam Hashemi, Prajin Joseph + Show 4 more

Open Access

https://doi.org/10.1016/j.biteb.2021.100874

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Abstract

Lignocellulose is readily available biomass for biogas production; however, due to its rigid structure, it requires pretreatment to obtain a maximum energy extraction. In this study, steam explosion (SE) (220 °C and 10 minute retention time) has been employed to increase the biogas production potential from birch wood. Although the biogas production increased by over two times after SE, the SE of birch wood negatively affects the structure of C5/C6 sugars and doubled the concentration of non-degradable lignin in all the samples. In this work, SE birch wood has been further pretreated by novel lignin-degrading enzymes cocktail to convert lignin into degradable sugars and increase the biogas production rate. The proposed hybrid pretreatment could increase the biogas production by up to 25% (from 450.5 mL/g VS to 566 mL/g VS), and reduced the lignin concentration by up to 48%.

Highlights

Industrial development has made human societies more dependent on energy in a way that the global energy consumption is increasing
There was a risk of losing some of volatile organics during the pressure release step that could lead to lower biogas production potential of the final samples
According to the results, proposed approach increases biogas yield compared to the unpretreated sample as well as the steam-exploded birch wood (SEBW) sample; inefficient enzymatic pretreatment can negatively affect the biogas yield

Summary

Introduction

Industrial development has made human societies more dependent on energy in a way that the global energy consumption is increasing. The total global energy supply became greater from 420 EJ in 2000 to 598 EJ in 2018 (World Bioenergy Association (WBA), 2020). The share of renewable energy sources in different end use sectors including electricity, heating and transportation was 17% in 2018 that was 58% more than that in 2000 (World Bioenergy Association (WBA), 2020). To avoid reaching a tipping point in the climate system (i.e., irreversible point in global warming), a fast switch to renewable energy sources is needed. In 2018, the global biogas pro duction reached 1.39 EJ that is an extreme increase compare to 0.28 EJ in 2000 (IEA, 2020; Ian Tiseo, 2021). It is predicted that by the end of 2050 the global biogas production potential from lignocellulosic material can reach up to 100 EJ (Haberl et al, 2010)

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