Background:
\nFermentations using Escherichia coli KO11, Saccharomyces cerevisiae 424A(LNH-ST), and Zymomonas mobilis AX101 are compared side-by-side on corn steep liquor (CSL) media and the water extract and enzymatic hydrolysate from ammonia fiber expansion (AFEX)-pretreated corn stover.
\nResults:
\nThe three ethanologens are able produce ethanol from a CSL-supplemented co-fermentation at a metabolic yield, final concentration and rate greater than 0.42 g\/g consumed sugars, 40 g\/L and 0.7 g\/L\/h (0-48h), respectively. Xylose-only fermentation of the tested ethanologenic bacteria are five to eight times faster than 424A(LNH-ST) in the CSL fermentation.All tested strains grow and co-ferment sugars at 15% w\/v solids loading equivalent of ammonia fiber explosion (AFEX)-pretreated corn stover water extract. However, both KO11 and 424A(LNH-ST) exhibit higher growth robustness than AX101. In 18% w\/w solids loading lignocellulosic hydrolysate from AFEX pretreatment, complete glucose fermentations can be achieved at a rate greater than 0.77 g\/L\/h. In contrast to results from fermentation in CSL, S. cerevisiae 424A(LNH-ST) consumed xylose at the greatest extent and rate in the hydrolysate compared to the bacteria tested.
\nConclusions:
\nOur results confirm that glucose fermentations among the tested strains are effective even at high solids loading (18% by weight). However, xylose consumption in the lignocellulosic hydrolysate is the major bottleneck affecting overall yield, titer or rate of the process. In comparison, Saccharomyces cerevisiae 424A(LNH-ST) is the most relevant strains for industrial production for its ability to ferment both glucose and xylose from undetoxified and unsupplemented hydrolysate from AFEX-pretreated corn stover at high yield.<\/p>\n","protected":false},"excerpt":{"rendered":"
Background: Fermentations using Escherichia coli KO11, Saccharomyces cerevisiae 424A(LNH-ST), and Zymomonas mobilis AX101 are compared side-by-side on corn steep liquor (CSL) media and the water extract and enzymatic hydrolysate from ammonia fiber expansion (AFEX)-pretreated corn stover. Results: The three ethanologens … Continue reading