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Fig. 2 | Biotechnology for Biofuels and Bioproducts

Fig. 2

From: A Vibrio-based microbial platform for accelerated lignocellulosic sugar conversion

Fig. 2

Improved xylose catabolism via ALE and elucidation of mutational mechanisms. A Predicted metabolic pathway of glucose, xylose, and arabinose in the VXA38 strain and genetic context of the region with major effective mutations. Key pathways are colored in yellow (glycolysis), gray (pentose phosphate pathway), pink (tricarboxylic acid cycle), blue (arabinose utilization pathway), and green (xylose isomerase pathway). Light and dark green indicate xylose isomerase (xylA) and xylulokinase (xylB), respectively. Light brown indicates the transcription factor for mannitol utilization family proteins (deoR), a putative repressor for atlA, xylB, and atlT. yrkL, atlA, and atlT encode NADH oxidoreductase, D-arabitol 4-dehydrogenase, and MFS superfamily transporters, respectively. Xylulose 5-phosphate is abbreviated as X5P. B Specific growth rates and xylose uptake rates of the isolates Blue indicates the maximum specific growth rate, and red indicates the specific xylose consumption rate. The subset graph indicates the specific growth rates in each flask during the ALE experiment. Red arrows indicate flasks selected for evolved clone isolation. C Mutation analysis of the starting and evolved strains. The red boxes indicate the presence of mutations. V55Hfs2X means that the 55th amino acid was changed from valine to histidine (V55H) and the stop codon was generated after 2 amino acids (57th) owing to the frameshift (fs2X). X indicates the generation of a stop codon. D Cell growth (optical density at 600 nm, OD600) over time with xylose minimal medium. Symbols: black circle, VXA38C (VXA38-1 with empty vector); green square, VXA38Y (VXA38-1 with additional yrkL expression); purple diamond, VXA38D (VXA38-1 with additional deoR expression). E Relative amounts of xylB transcripts in the VXA38C and VXA38D strains. F Catalytic efficiencies (kcat/Km in min−1 mM−1) of wild-type (VXW) and mutant (VXM) xylose isomerase G Normalized specific fluorescence of strains expressing the xylA-sgfp fused protein under the original PJ23100 (VXPW) and mutant promoter (VXPM)

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