Pretreatment of lignocelluloses for enhanced biogas production: A review on influencing mechanisms and the importance of microbial diversity
Laen...
Kuupäev
2021
Kättesaadav alates
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Elsevier
Abstrakt
As one of the most efficient methods for waste management and sustainable energy production, anaerobic
digestion (AD) countenances difficulties in the hydrolysis of lignocelluloses biomass. Different pretreatment
methods have been applied to make lignocelluloses readily biodegradable by microorganisms. These pretreatments
can affect biogas yield by different mechanisms at molecular scale, including changes in chemical
composition, cellulose crystallinity, degree of polymerization, enzyme adsorption/desorption, nutrient accessibility,
deacetylation, and through the formation of inhibitors. The present article aims at critically reviewing the
reported molecular mechanisms affecting biogas yield from lignocelluloses via different types of pretreatments.
Then, a new hypothesis concerning the impact of pretreatment on the microbial community developed
(throughout the AD process from an identical inoculum) was also put forth and was experimentally examined
through a case study. Four different leading pretreatments, including sulfuric acid, sodium hydroxide, aqueous
ammonia, and sodium carbonate, were performed on rice straw as model lignocellulosic feedstock. The results
obtained revealed that the choice of pretreatment method also plays a pivotally positive or negative role on
biogas yield obtained from lignocelluloses through alteration of the microbial community involved in the AD.
Considerable changes were observed in the archaeal and bacterial communities developed in response to the
pretreatment used. Sodium hydroxide, with the highest methane yield (338 mL/g volatile solid), led to a partial
switch from acetoclastic to the hydrogenotrophic methane production pathway. The findings reported herein undermine the default hypothesis accepted by thousands of previously published papers, which is changes in
substrate characteristics by pretreatments are the only mechanisms affecting biogas yield. Moreover, the results
obtained could assist with the development of more efficient biogas production systems at industrial scale by
offering more in-depth understanding of the interactions between microbial community structure, and process
parameters and performance.
Kirjeldus
Received 13 August 2019; Received in revised form 10 July 2020; Accepted 28 July 2020, Available online 11 August 2020.
Märksõnad
lignocellulosic substrate, pretreatment, influencing mechanism, methane, microbial community, anaerobic digestion, articles