Syngas Derived from Lignocellulosic Biomass Gasification as an Alternative Resource for Innovative Bioprocesses

Abstract

A hybrid system based on lignocellulosic biomass gasification and syngas fermentation represents a second-generation biorefinery approach that is currently in the development phase. Lignocellulosic biomass can be gasified to produce syngas, which is a gas mixture consisting mainly of H2, CO, and CO2. The major challenge of biomass gasification is the syngas’s final quality. Consequently, the development of effective syngas clean-up technologies has gained increased interest in recent years. Furthermore, the bioconversion of syngas components has been intensively studied using acetogenic bacteria and their Wood–Ljungdahl pathway to produce, among others, acetate, ethanol, butyrate, butanol, caproate, hexanol, 2,3-butanediol, and lactate. Nowadays, syngas fermentation appears to be a promising alternative for producing commodity chemicals in comparison to fossil-based processes. Research studies on syngas fermentation have been focused on process design and optimization, investigating the medium composition, operating parameters, and bioreactor design. Moreover, metabolic engineering efforts have been made to develop genetically modified strains with improved production. In 2018, for the first time, a syngas fermentation pilot plant from biomass gasification was built by LanzaTech Inc. in cooperation with Aemetis, Inc. Future research will focus on coupling syngas fermentation with additional bioprocesses and/or on identifying new non-acetogenic microorganisms to produce high-value chemicals beyond acetate and ethanol.

Xylose Metabolism in Bacteria—Opportunities and Challenges towards Efficient Lignocellulosic Biomass-Based Biorefineries

“…The conversion of organic solid matter through lignocellulosic gasification into a gaseous mixture of H 2 , CO, CO 2 , and CH 4 is another approach for LB valorization. The obtained synthetic-"syngas"-can be directly used as combustible for energy generation or as feedstock for chemical or biological processes [22]. Strict anaerobes, mostly acetogens, are used for syngas conversion to organic acids, alcohols, and other chemicals by "indirect fermentation"(as in this process, the biomass is previously converted to syngas and only then fed to microorganisms) [22,23].…”

Development of 2,3-Butanediol Production Process from Klebsiella aerogenes ATCC 29007 Using Extracted Sugars of Chlorella pyrenoidosa and Biodiesel-Derived Crude Glycerol

“…Previous studies reported that 2,3-BDO has been investigated from various strains and many substrates [10,21,23,24,27,28]. Among them, 2,3-BDO research was performed using biodiesel-derived crude glycerol from K. aerogenes ATCC 29007.…”

“…2,3-BDO, a chemical substance that can be produced by the biomass conversion process through fermentation of microorganisms, has a strong hydrophilic property as a colorless and odorless chiral compound in liquid or crystal form [21][22][23]. Because it has a low freezing point, −60 • C, it can be used as antifreeze.…”

Reactor Designs and Configurations for Biological and Bioelectrochemical C1 Gas Conversion: A Review

“…Syngas, a gas mixture primarily composed of CO, H 2 , and CO 2 , has attracted considerable interest as a raw material for the production of biofuels and biochemicals via anaerobic fermentation processes such as syngas fermentation [ 1 ], microbial chain elongation [ 2 ], hydrogenotrophic methanation [ 3 ], and microbial assisted bioelectrochemical synthesis (BES) for conversion of CO 2 /CO [ 4 ]. Syngas can be generated via gasification of solid fuels such as coal and lignocellulosic biomass, which is an effective way of making use of the recalcitrant lignin present in lignocellulosic biomass [ 5 , 6 ]. In addition, CO is the major byproduct of incomplete combustion of carbonaceous materials such as coal, oil, and petroleum products, and it has been generated and discharged in significant quantities by related sectors such as steel industries [ 7 ].…”