In this work, the self-assembly behavior of cetyltrimethylammonium bromide (CTAB) on the surface of citrate-capped gold nanoparticles (AuNPs) in solution has been studied by UV−vis absorption spectroscopy, fluorescence probe techniques, ζ potentiometric methods, transmission electron microscopy, etc. The UV−vis spectra show that the color with the increase of CTAB for the mixture containing CTAB and a given amount of AuNPs changes from red to blue and then to red.The absolute value of ζ potential corresponding to this color change decreases initially and then increases. Specially, the reversible color change, from red to blue and then to red, could be observed only in the case of a gradual addition of a AuNP solution to a CTAB solution; however, this reversible change is not suitable for the mixture formed in a reverse order of mixing. The results from pyrene used as the fluorescence probe indicate that the features in the fluorescence spectrum (including fluorescence quenching, I 1 /I 3 , and the excimer) well correspond to those from the UV−vis spectrum mentioned above. Based on the experimental results, the mechanism of the assembly structure variation of CTAB on the surface of negatively charged AuNPs was proposed. For a given amount of AuNPs, the assembly structure of CTAB on the surface of AuNPs undergoes the transformation from a monolayer to a bilayer with the increase of CTAB. In the case of the concentration of CTAB far beyond its critical micelle concentration (CMC) and the higher ratio of CTAB and AuNPs, there is a possibility of the formation of an extra micellar structure only after the formation of a double-layer structure.

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Genetic diversity is an important factor affecting the efficiency of adaptive laboratory evolution (ALE). The recent development of precise tools and strategies for genomic engineering has greatly accelerated mutant library construction for ALE. Here, a global regulator library based on the CRISPR-enabled trackable genome engineering (CREATE) technology was first used to accelerate adaptive evolution for improved furfural tolerance in Escherichia coli, and the furfural tolerance was increased approximately 2-fold in the genetically diversified CREATE-based strains. The evolved strain tolerated up to 4.7 g/L furfural and also showed marked cross-tolerance to NaCl, isobutanol, butanol, ethanol, and high temperature. Whole-genome sequencing and mutant reconstruction analysis revealed for the first time that rpoB P153L mutation leads to greatly increased furfural tolerance. The expression of genes coding central carbon and energy metabolism was significantly altered according to transcriptome analysis. In particular, it was confirmed for the first time that the knockout of sRNA sgrS and the overexpression of sRNA arrS significantly increased furfural tolerance. This study provides evidence that combined ALE and the CREATE technology can not only obtain highly efficient strains with favorable mutation combinations but also accelerate ALE by providing much greater genomic and functional diversity.