Biological abatement of inhibitors in rice hull hydrolyzate and fermentation to ethanol using conventional and engineered microbes

Physico-Chemical Conversion of Lignocellulose: Inhibitor Effects and Detoxification Strategies: A Mini Review

“…To avoid energy intensive processing conditions, harsh chemicals and expensive processing materials, an environmentally-friendly way to implement a detoxification process, using specific microbes, was also investigated. In this strategy, microorganism pretreatment could alleviate and/or eliminate lignocellulosic-derived inhibitors before enzymatic hydrolysis and subsequent fermentation [ 84 , 133 , 134 , 151 , 152 ]. Several microorganisms, such as Coniochaeta ligniaria , Paecilpmyces variotii , Urebacillus thermosphaericus , and genetically modified S. cerevisiae were suggested and evaluated the alleviation of the inhibitors prior to enzyme digestion and microbial fermentation [ 84 , 136 , 144 ].…”

“…Nichols et al [ 135 ] identified C. ligniaria NRRL30616 was an ideal candidate as it had increased tolerance to inhibitory compounds and could metabolize these inhibitors (mainly furans and acetate) as a carbon source and energy. The use of C. ligniaria was also suitable in the reduction of inhibitors formed during diluted acid pretreatment of different biomass, such as switchgrass, reed canarygrass, alfalfa stem, corn stover, and rice hull, resulting in confirmation ethanol productions with a short lag phase [ 134 , 135 , 136 , 151 ]. Especially, the utilization of C5 sugars such as pentose and arabinose in the biologically detoxified hydrolysates with C. ligniaria was available to improve the ethanol production using a recombinant bacterium, Escherichia coli FBR5.…”

Study on inhibitors from acid pretreatment of corn stalk on ethanol fermentation by alcohol yeast

“…Inhibitors formed during dilute acid hydrolysis of biomass include furan aldehydes furfural and 5-hydroxymethylfurfural (HMF) derived from sugar degradation, acetate from hemicellulose, and a number of aromatic aldehydes and acids from lignin. 16 Table 2 is monosaccharide compositions of the hydrolyzate from corn aer pretreatment with different concentrations of sulfuric acid. The concentrations of monosaccharide decreased with the increases of sulfuric acid concentration.…”

Draft Genome Sequence of Coniochaeta ligniaria NRRL 30616, a Lignocellulolytic Fungus for Bioabatement of Inhibitors in Plant Biomass Hydrolysates

“…C. ligniaria NRRL 30616 was isolated from furfural-contaminated soil based on its ability to metabolize furan-aldehyde mixtures ( 2 ). This strain has the potential to remove a variety of inhibitory compounds (e.g., 5-hydroxymethylfurfural) from plant biomass (e.g., wheat straw, switchgrass, corn stover, alfalfa stems, and rice hulls) dilute-acid hydrolysates, facilitating subsequent microbial fermentation of sugars ( 3 – 6 ). Moreover, C. ligniaria –like isolates have also been recovered from torrefied grass ( 7 ) as well as from various soil-derived lignocellulolytic microbial consortia ( 8 , 9 ).…”