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2,3‐Butanediol (2,3‐BDO) is a promising bulk chemical owing to its high potential in industrial applications. Here, we engineered Klebsiella oxytoca for the economic production of 2,3‐BDO using mixed sugars from renewable biomass. First, to improve xylose consumption, the xylose transporter gene (xylE) was integrated into the methylglyoxal synthase A (mgsA)‐coding gene loci, and the engineered CHA004 strain showed much faster consumption of xylose than wild‐type (WT) strain with 1.4‐fold increase of overall sugar consumption rate. To further improve sugar utilization, we performed adaptive laboratory evolution for 90 days. The evolved strain (CHA006) was evaluated by cultivating it in the media containing single‐ or mixed‐sugars, and it was clearly observed that CHA006 has improved sugar consumption and 2,3‐BDO production than those of the parental strain. Finally, we demonstrated the superiority of CHA006 by culturing in two lignocellulosic hydrolysates derived from sunflower or pine tree. Particularly, in the pine tree hydrolysate containing xylose, glucose, galactose, and mannose, the CHA006 strain showed much improved consumption rates for all sugars, and 2,3‐BDO productivity (0.73 g L−1 hr−1) increased by 3.2‐fold compared to WT strain. We believe that the engineered CHA006 strain can be a potential host in the development of economic bioprocess for 2,3‐BDO through efficient utilization of mixed sugars derived from lignocellulosic biomass.

In this study, we investigated the electrical and thermal properties of SiC ceramics with 2 vol% equimolar Y2O3–RE2O3 (RE = Sm, Gd, Lu) additives. The three SiC ceramics with 2 vol% equimolar Y2O3–RE2O3 additives showed electrical conductivities on the order of ~103 (Ω·m)−1, which is one order of magnitude higher than that of the SiC ceramics sintered with 2 vol% Y2O3 only. The increase in electrical conductivity is attributed to the growth of heavily nitrogen-doped SiC grains during sintering and the confinement of oxide additives in the junction area. The thermal conductivities of the SiC ceramics were in the 176–198 W·(m·K)−1 range at room temperature. The new additive systems, equimolar Y2O3–RE2O3, are beneficial for achieving both high electrical conductivity and high thermal conductivity in SiC ceramics.

SiC–TiC0.5N0.5 composites were fabricated from β-SiC and TiN powders with 2 vol% equimolar Y2O3–Sc2O3 additives by conventional hot pressing. Thermal and mechanical properties of the SiC–TiC0.5N0.5 composites were investigated as a function of initial TiN content. Relative densities of ≥98.9% were achieved for all samples. The addition of a small amount of TiN increased thermal conductivity, flexural strength, and fracture toughness of SiC ceramics. However, further addition of TiN in excess of 10 and 20 vol% deteriorated both thermal conductivity and flexural strength of the composites, respectively. In contrast, the fracture toughness of the composites increased continuously from 4.2 to 6.2 MPa∙m1/2 with increasing initial TiN content from 0 to 35 vol%, due to crack deflection by TiC0.5N0.5. The maximum values of thermal conductivity and flexural strength were 224 W/m K for a 2 vol% TiC0.5N0.5 and 599 MPa for a 10 vol% TiC0.5N0.5 composite.