The Breeding of Bioethanol-Producing Yeast by Detoxification of Glycolaldehyde, a Novel Fermentation Inhibitor

Author(s):  
Lahiru N. Jayakody ◽  
Nobuyuki Hayashi ◽  
Hiroshi Kitagaki
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Liang Sun ◽  
Jae Won Lee ◽  
Sangdo Yook ◽  
Stephan Lane ◽  
Ziqiao Sun ◽  
...  

AbstractPlant cell wall hydrolysates contain not only sugars but also substantial amounts of acetate, a fermentation inhibitor that hinders bioconversion of lignocellulose. Despite the toxic and non-consumable nature of acetate during glucose metabolism, we demonstrate that acetate can be rapidly co-consumed with xylose by engineered Saccharomyces cerevisiae. The co-consumption leads to a metabolic re-configuration that boosts the synthesis of acetyl-CoA derived bioproducts, including triacetic acid lactone (TAL) and vitamin A, in engineered strains. Notably, by co-feeding xylose and acetate, an enginered strain produces 23.91 g/L TAL with a productivity of 0.29 g/L/h in bioreactor fermentation. This strain also completely converts a hemicellulose hydrolysate of switchgrass into 3.55 g/L TAL. These findings establish a versatile strategy that not only transforms an inhibitor into a valuable substrate but also expands the capacity of acetyl-CoA supply in S. cerevisiae for efficient bioconversion of cellulosic biomass.


2011 ◽  
Vol 50 (24) ◽  
pp. 14055-14060 ◽  
Author(s):  
Kuang Zhang ◽  
Manoj Agrawal ◽  
Justin Harper ◽  
Rachel Chen ◽  
William J. Koros

2011 ◽  
Vol 77 (15) ◽  
pp. 5132-5140 ◽  
Author(s):  
X. Wang ◽  
E. N. Miller ◽  
L. P. Yomano ◽  
X. Zhang ◽  
K. T. Shanmugam ◽  
...  

ABSTRACTFurfural is an important fermentation inhibitor in hemicellulose sugar syrups derived from woody biomass. The metabolism of furfural by NADPH-dependent oxidoreductases, such as YqhD (lowKmfor NADPH), is proposed to inhibit the growth and fermentation of xylose inEscherichia coliby competing with biosynthesis for NADPH. The discovery that the NADH-dependent propanediol oxidoreductase (FucO) can reduce furfural provided a new approach to improve furfural tolerance. Strains that produced ethanol or lactate efficiently as primary products from xylose were developed. These strains included chromosomal mutations inyqhDexpression that permitted the fermentation of xylose broths containing up to 10 mM furfural. Expression offucOfrom plasmids was shown to increase furfural tolerance by 50% and to permit the fermentation of 15 mM furfural. Product yields with 15 mM furfural were equivalent to those of control strains without added furfural (85% to 90% of the theoretical maximum). These two defined genetic traits can be readily transferred to enteric biocatalysts designed to produce other products. A similar strategy that minimizes the depletion of NADPH pools by native detoxification enzymes may be generally useful for other inhibitory compounds in lignocellulosic sugar streams and with other organisms.


1959 ◽  
Vol 5 (1) ◽  
pp. 135-142 ◽  
Author(s):  
Timothy Merz

The effects of extended anaerobic treatments on Vicia faba lateral root-tip chromosomes were determined. It was observed that aberrations resulted from these treatments, and that the frequency varied from root to root as well as from experiment to experiment. It was suggested that the inconsistency observed might be due to variation in the abilities of different roots to produce energy via fermentation routes. If this were true, an inhibition of fermentation would result in a more consistent aberration frequency. A fermentation inhibitor, NaF, was used in combination with extended anaerobic treatments. The observed frequency of aberrations after the combined treatments was generally higher and considerably less variable. Although other hypotheses might account for the NaF effect, the hypothesis most compatible with the evidence is that the effect is due to energy deprivation. The experimental results are discussed in terms of the aforementioned effect and in terms of three alternative hypotheses for the production of chromosomal aberrations as a consequence of a lack of energy. It is concluded that damage might result from a build-up of normal cellular compounds to abnormally high concentrations which would act directly or indirectly on the chromosomes, from the breakdown of DNA as an energy source, or simply as a result of the fact that the chromosome needs energy to remain intact.


Catalysts ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 476 ◽  
Author(s):  
Marco Kadowaki ◽  
Mariana Godoy ◽  
Patricia Kumagai ◽  
Antonio Costa-Filho ◽  
Andrew Mort ◽  
...  

Myceliophthora thermophyla is a thermophilic industrially relevant fungus that secretes an assortment of hydrolytic and oxidative enzymes for lignocellulose degradation. Among them is glyoxal oxidase (MtGLOx), an extracellular oxidoreductase that oxidizes several aldehydes and α-hydroxy carbonyl substrates coupled to the reduction of O2 to H2O2. This copper metalloprotein belongs to a class of enzymes called radical copper oxidases (CRO) and to the “auxiliary activities” subfamily AA5_1 that is based on the Carbohydrate-Active enZYmes (CAZy) database. Only a few members of this family have been characterized to date. Here, we report the recombinant production, characterization, and structure-function analysis of MtGLOx. Electron Paramagnetic Resonance (EPR) spectroscopy confirmed MtGLOx to be a radical-coupled copper complex and small angle X-ray scattering (SAXS) revealed an extended spatial arrangement of the catalytic and four N-terminal WSC domains. Furthermore, we demonstrate that methylglyoxal and 5-hydroxymethylfurfural (HMF), a fermentation inhibitor, are substrates for the enzyme.


2013 ◽  
Vol 27 (10) ◽  
pp. 5975-5981 ◽  
Author(s):  
Yunchao Li ◽  
Jingai Shao ◽  
Xianhua Wang ◽  
Haiping Yang ◽  
Yingquan Chen ◽  
...  

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