Engineering and Two-Stage Evolution of a Lignocellulosic Hydrolysate-Tolerant Saccharomyces cerevisiae Strain for Anaerobic Fermentation of Xylose from AFEX Pretreated Corn Stover
Figure 2
The GLBRCY127 strain developed by directed engineering with xylose isomerase coupled with batch evolution can rapidly consume xylose aerobically.
Average sugar consumption and cell growth of unevolved GLBRCY22-3 strain engineered with ScTAL1, CpxylA and SsXYL3 cultured in bioreactors containing YPDX media and sparged with air from biological duplicates is shown (A). Indicated components were quantified from media samples at times from initial inoculation. In (B), the average percentage of xylose consumed and change in cell density per day are plotted for each transfer during the adaption of the Y22-3 strain in YP media containing 0.1% glucose and 2% xylose. The pattern of lower % of xylose consumed and change in cell density per day during every third transfer is due to reaching saturated growth prior to transfer. Average extracellular xylose concentrations and cell density measurements from parental Y22-3 and evolved Y127 strains grown aerobically in culture tubes with YPX media from three independent biological replicates are plotted in (C). In (D), evolved isolate Y127 was cultured in the same conditions as in (A), and samples measurements taken in an identical manner.